Class cJ 6 ^f3 Lj "^ c^ Book n /jc l^ Copyright W COPYRIGHT DEPOSIT. FERTILITY AND FERTILIZER HINTS M Published by N M M H M The Chemical Publishing Co. | Easton, Penna. m I8« Publishers of Scientific Books H M Engineering Chemistry Portland Cement g g Agricultural Chemistry Qualitative Analysis ^ g Household Chemistry Chemists' Pocket Manual g lei Metallurgy, Etc. g KX2iXIXa^II3J^IXXSSXI-XXIXXXXI-XX3Ed^^X«-X3^X'XXX-IXX-XXI2S Fertility anc Fertilizer Hints By JAMES EDWARD HALLIGAN CHEMIST IN CHARGE. LOUISIANA STATE EXPERIMENT STATION EASTON, PA. THE CHEMICAL PUBLISHING CO. 1911 LONDON, ENGLAND: WILLIAMS & NORGATE 14 HENRIETTA STREET, COVENT GARDEN, W. C. Copyright, 1911, hv Edward Hart. Vv ©CI.A80 5i)0 PREFACE. Tlie little book is an abridged edition of tlie autbor"s. Soil Fertility and Fertilizers. The symbol* has been nsed throui^hont the text to refer to notes, in the back of the book, that state the topics of subject matter that have necessarily been omitted in this work. This book has been written to be within the reach of the farmer, student, or any other person interested in the subject, "Fertilizers," and should more complete data be desired the unabridged edition. Soil Fertility and Fertilizers should be con- sulted. The writer is indebted to the Louisiana Experiment Station, for illustrations. T. E. HALLIGAN. Baton Rouoe. La. CONTENTS. CHAPTER I— Chemical Elements Needed by Plants and the Composition of Plants i-i 2 The Fifteen Elements. How Plants Feed. The Food of the Plant. Composition of Plants. Amounts of Water Used by Plants. Water in Young and Mature Plants. Dry Matter of Plants. Composition of the Dry Matter of Plants. Acids and Bases. Salts. Vari- ation of Ash. Occurrence of Mineral Elements in Plants. Distribution of Ash in Plants. Ash of Young and Mature Plants. CHAPTER II— The Fertility of the Soil 13-24 Composition of Soils. Factors Influencing Soil Fer- tility. The Plant F'ood Supply. Plant Food Removed by Some Crops. Plant Food not Available. The Es- sential Elements. One Element Cannot Replace An- other. Physical Condition of the Soil. Temperature. Mechanical Composition. Surface Area of Soil Grains. Lumpy Soil. Cracking of Soils. Puddling of Soils. Freezing and Thawing. Plants are Benefited by Open Soils. Plants Must Have Room. Plants Require Oxygen. Drainage. Capillary Water. The Biological Condition of the Soil. The Number of Bacteria in the Soil. Nitrification. Denitrification. Organisms that Gather Nitrogen. Inoculation of the Soil. CHAPTP:R III— Maintaining Soil Fertility 25-34 Erosion and Ways to Check It. Loss of Fertility by- Drainage. Fallowing. Loss of Nitrogen by Continu- ous Cropping. Losses of Phosphoric Acid and Potash. One Crop Farming. Diversification and Rotation of Crops. Make up of a Rotation. Reasons for Rotating Crops. Rotation Keeps Down Weeds. Legumes are Profitable. Rotation Helps to Distribute Farm Labor. Rotation Helps to Check or Eradicate Insects and Plant Diseases. It Furnishes Feed for Live Stock. It Allows a Regular Income. It Prevents Losses of Fer- tility. It Utilizes Plant Food More Evenly. It Saves Fertilizer Expenditure. It Regulates the Humus Sup- ply. System of Farming. CONTENTS V CHAPTER IV— Farm Manures 35-47 Kind of Manure. Conditions Affecting the Value of Manure. The Age of the Animal. The Use of the Animal. The Kind of Bedding and Amount Infiuence.s the Value of Manure. Straw. Leaves. Sawdust. Peat. Absorptive Power of Bedding. Horse Manure. Cow- Manure. Hog Manure. Sheep Manure. Hen Ma- nure. Analyses of Farm Manures. How to Calculate the Amount of Manure Produced. The Nature and Amount of Feed Used Affects the Value of Manure. Lasting Effect of Manure. Care, Preservation, and Use of Manure. Waste of Manure. Leaching. Fer- mentations. Keep Manure Moist. Composting Ma- nure. Store Manure Under Cover. Preservatives. Physical Effects of Manure. Manure Produces a Bet- ter Moisture Condition. It Improves the Texture of the Soil. It Prevents Mechanical Loss by Winds. It Benefits Grass Land. Bacteriological Effects of Ma- nure. Time to Apply. Amount to Apply. How to Apply. CHAPTER V High Grade Nitrogenous Materials.. 4^-59 Forms of Nitrogen. The Meaning of the Form of Nitrogen. The Vegetable Substances. Cotton-Seed Meal. Composition of Cotton-Seed Meal. Value of Cotton-Seed Meal. Linseed Meal. Castor Pomace. The Chief .Animal Substances. Dried Blood. Tankage. Grades of Tankage. Variation in Tankage. Azotin. Steamed Horn and Hoof Meal. Dry Ground Fish. King Crab. Guano. Ammonium Sulphate. Compo- sition and Availability. Nitrate of Soda. Composition and Properties of Nitrate of Soda. Calcium Nitrate. Calcium Cyanamid. Properties of. Fertilizing Value of. CHAPTER VI Low Grade Nitrogenous Materials and Functions of Nitrogen 60-69 Raw Leather Meal. Dissolved Leather. Feather Waste. Hair and Fur Waste. Mora Meal. Beet Refuse. Scutch. Horn and Hoof Meal. Wool Waste, Shoddies, Etc. Garbage Tankage. Dried Peat. Avail- ability of Nitrogenous Materials. Value of Low Grade Materials. Use of Low Grade Materials is Increasing. Nitrogenous Materials to Use. Functions of Nitrogen. Excessive Nitrogen Invites Diseases. VI CON TK NTS CHAPTER VII -Phosphates 70-79 Bones. Raw Bone-Meal. Steamed Botie-Meal. De- gree of Fineness. Bone-Black. Bone-Ash. Bone Tankage. Dry Ground Fish. Mineral Phosphates. South Carolina Phosphates. Florida Phosphates. Tennessee Phosphates. Canadian Apatite. Rodunda Phosphate. Basic Slag. Phosphatic Guanos. Classifi- cation of Phosphates. Form of the Phosphates. Availability of the Phosphates. CHAPTER VIII— Superphosphates and Effect of Phos- phoric Acid 80-89 Manufacture of Super or Acid Phosphate. Phosphates of Lime. Insoluble Phosphoric Acid. Soluble Phos- phoric Acid. Reverted Phosphoric Acid. Basic Slag Phosphate. Value of Reverted Phosphoric Acid. Dif- ference Between Phosphate and Superphosphate. Names Applied to Superphosphates. Available Phos- phoric Acid. The Difference in the Formsof Phosphoric Acid in Superphosphates. Some People Favor Bone Superphosphates. Double Superphosphates. No Free Acid in Treated Phosphates. The Color of an Acid Phosphate. How to Made Superphosphate at Home. Amount of Phosphoric Acid in Soils. Fixation of Phosphoric Acid. Functions of Phosphoric Acid. The Kind of Phosphate to U.se. CHAPTER IX— Potash Fertihzers go-97 Potash Salts (Stassfurt). History of. Kinds of. Kainit. Sylvinit. Muriate of Potash. Sulphate of Potash. Double Sulphate of Potash and Magnesia. Potash Manure Salts. Potassium-Magnesium Car- Vjonate. Potash from Organic Sources. Wood Ashes. Value of Wood Ashes. Tobacco vStems and Stalks. Cotton-Seed Hull Ashes. Carbonate of Potash. Beet Molasses. Amount of Potash in vSoils. Forms of Potash. Fixation of Potash. Functions of Potash. Potash Favors Seed Formation. It E^fifects the Leaves and Maturity. It Neutralizes Plant Acids. It Checks Insect Pests and Plant Diseases. CHAPTER X— Miscellaneous PVrtilizer Materials. . . . 98-103 Compost. Seaweed. Marl. Peat and Muck. Pul- verized Manures. Fresh Fish and P'resh Fish Wastes. Sewage and Sewage Sludge. Coal Ashes. Lime Kiln Ashes. Rice Hull Ashes. Corn Cob Ashes. Brick COXTKXTS Vll Kiln Ashes. Soot. Street Sweepings. Potas.siuni Nitrate. Atnnioniuni Nitrate. Silicate of Potash. Iron Sulphate. Common Salt. Powder Waste. Sul- phates of Magnesia and Soda. Carbonate of Magnesia. Ammonium Chloride. Manganese Salts. CHAPTER XI — Lime, Gypsum aud Green Mainire.s. . 104-111 Lime. Forms of. When Soils Need Lime. How to Find Out When Soils are Acid. How to Apply Lime. The Form to Use. Amount of Lime to Apply. Le- gumes Require an Alkaline Soil. Mechanical Action of Lime. Lime Decreases the Action of Some Fungus Diseases. Gas Lime. Gypsum. Green Manures. Classes of. The Best Time to Plow Under a Green Manure. The Time to Grow a Green Manure. Deep Rooted Plants Valuable. CHAPTER XII— Commercial Fertilizers 1 12-1 18 Causes of the Large Consumption of Fertilizers. Fer- tilizer Materials Used by Manufacturers. Basis of Pur- chase. Unit and Ton Basis. Fertilizer Laws. The Meaning and the Interpretation of the Guarantee. CHAPTER XIII — Valuation of Fertilizers 1 19-125 Interpretation of Chemical Analyses. Agricultural Values. Commercial Values. Trade Values. How Obtained. A Discussion of the Table of Trade Values. How to Calculate Commercial Values. CHAPTER XIV— Home Mixtures 126-133 Definitions. Manufacturers' Claims Against Home Mixing. Reasons Why Farmers Should Mix Fertili- zers at Home. Home IMi.xing Acquaints the Farmer with Materials Used. Home ]\(ixing Does Away With the Purchase of Unnecessary Constituents. How to Mix Fertilizers at Home. How to Calculate Percent- ages from Known Amounts. How to Calculate Amounts from Known Percentages. CHAPTER XV— A Few Remarks about Fertilizers . . 134-143 Brand and Trade Names. How to Purchase a Ferti- lizer. Study the Guarantee. F'ertilizers Should Reach their Guarantees. Fertilizers do not Deteriorate Much on Standing. The Time to Apply Fertilizers. How Fertilizers are Applied. Is it Profitable to U.se Fer- tilizers? Amount of Fertilizer to use. CHAPTER I. CHEMICAL ELEMENTS NEEDED BY PLANTS AND THE COMPO- SITION OF PLANTS. Ill order to thoroughly understand the subject "fertiHzers," we must become familiar with the chemical elements needed by plants. There are about 8i chemical elements known to us, but only 15 of these are required for plant life so far as we know. The Fifteen Elements. — Hydrogen, oxygen, nitrogen, carbon, potassium, phosphorus, calcium, sulphur, silicon, iron, chlorine, magnesium, sodium, aluminum and manganese are the elements used by plants. Hydrogen, oxygen, nitrogen and chlorine, in the pure state, generally occur as gases, while the other ele- ments are solids. The Symbols. — The chemist uses the following symbols for these elements. Hydrogen (H) Oxygen (O) Nitrogen (N) Carbon (C) Potassium (K) Phosphorus (P ) Calcium (Ca) Sulphur (S) vSilicon(Si) Iron (Fe) Chlorine (CI) Magnesium (Mg) Sodium (Na) Aluminum (Al) Manganese ( Mn) Small amounts of oxygen are sometimes used by plants in the elementary state. Certain plants also use nitrogen in the free state. All other elements, and generally oxygen and nitrogen must be combined with other of these elements to be favorable for the support of plant life. Hydrogen. — This is a colorless invisible gas, having no smell or taste. It is generally found in combination with other ele- ments as water, hydrochloric acid, marsh gas, sulphuretted hy- drogen, all acids and most organic (animal and vegetable) com- pounds. It is most cotnmonly found as water (H.O), which is the most necessary food of the plant. In the free state hydro- gen occurs only in small quantities upon the earth in the gases of petroleum wells, around volcanic eruptions, and it is evolved by the fermentation and decomposition of some organic sub- stances. 2 FERTIUTV AND FHRTILIZKR IIIXTS Oxygen. — In the free gaseous state, about one-fifth, by bulk, of the atmosphere is made up of this element, mechanically mixed with nitrogen. It is found in enormous quantities in combination with other elements. It constitutes about eight- ninths by weight of water and nearly one-half of the earth's crust. All combustion and decay require oxygen. The plant stores up oxygen in combination with other elements and with- out oxygen plants would die. The plant takes in oxygen, from the atmosphere, in combination with carbon, as carbonic acid gas, through the openings on the under sides of the leaves ; the carbon is absorbed and the excess of oxygen given off. Oxygen combines with most other elements forming oxides. It often combines with other elements in varied amounts forming oxides of diff'erent composition which are generally quite stable. The color of soils is often determined by oxides such as iron oxides. The iron oxides influence the moisture condition of soils be- cause of their absorptive qualities and help to oxidize organic substances in the soil. The roots of plants when deprived of air in the soil are able to draw upon iron oxides for oxvgen. Nitrogen. — About four-fifths of the atmosphere, or about 35,000 Fig. I. — Cowpeas liave the power of gathering nitrogen from the air. tons over every acre of land, is made up of nitrogen in the free CIIKMICAL HLKMKXTS NEEDED BV I'LAXIS 3 gaseous state. In c()nil)inatiun this element is found in many substances such as ammonia, sodium nitrate (Chile saltpeter), potassium nitrate and many organic compounds. Certain plants. namely the legumes, of which the pea. bean, alfalfa, clovers, covvpea, soy bean. etc.. are members, have the power of gather- ing nitrogen from the air. by means of certain growths (tuber- cles) on their roots.* .-\lthough nitrogen is abundant in the free state it cannot be used as such by most plants and it must be combined with other elements to be available as plant food. Nitrogen as sold in fertilizers is in combination with other ele- ments, and is the most fugitive and expensive of the essential elements. This will be described more fully later on. Carbon. — This element is found in the free state in charcoal, graphite and diamonds. In coal it is also present in an impure state. Muck and peat contain considerable carbon. Humus (the decayed organic matter in soils) is made up partly of car- bon. In combination with oxygen we find carbon as carljon dioxide (carbonic acid gas) in the air. It is present in greater ((uantities in plant life than any other element. Henry^ says: ''10,000 volumes of air contain about 3 volumes of carbonic acid gas : 32 cubic yards of air hold one pound of this gas. An acre of growing wheat will gather during four months, 2,000 pounds of carbonic acid gas. or an amount equal to all the air contains over the same area of land to a height of three miles." All of our farm crops use a great amount of carbon in the form of carbonic acid gas. All carbonates (limestone, chalk, mar1)le. shells, etc. ) and all organic substances contain carljon. The car- bonates of lime found in the soil exert a great influence upon the conversion of some forms of nitrogen into available plant food and in the general physical condition of the soil. Potassium in combination is very common. It is mined in large quantities as potassium salts in the Stassfurt mines of .Germany. The presence of this element in wood ashes, as potassium car- bonate, makes this substance a valuable fertilizer. Potassium is found in most rocks and soils. In plants it is associated with organic acids. It is found in sea water and saltpeter. This 1 Feeds and Feeding. 4 FERTIIvITY AND FERTIUZER HINTS element is essential to plant growth and is found in the stems, leaves and fruits of plants. Phosphorus is found in combination with oxygen and metals, as phosphates. Vast deposits of phosphates are found in Tennes- see, South Carolina, Florida and some of the western states. It is present in many rocks and most soils and is an important element for plant food. It exists in combination with organic substances in plants and constitutes an important part of the ash of plants. Bones, which contain about 60-65 P^r cent, of cal- cium phosphate, are an important source of phosphorus for plant food. Calcium is an element which occurs in combination in many substances as lime, marble, shells, coral and gypsum. It makes up about one-sixteenth part of the earth's crust. Plants and animals require this element, sometimes in larger amounts than one would imagine. The bones of animals are made up largely of this element in combination as lime. Lime is a great factor in regulating the physical condition of soils. Sulphur. — This is a yellow substance which is found in the free state in large deposits in Louisiana, western LTnited States, and Sicily. It is found in combination in gypsum (an important indirect fertilizer), pyrites (a source of sulphuric acid), galena, etc. It is also found in many natural waters. In plants it oc- cupies an important place, occurring in organic compounds as protein, or nitrogenous portions, and also as sulphuric acid. Most of our soils are sufficiently supplied with this element for the nourishment of plants. Silicon occurs in combination as sand, flint, c[uartz, etc., and constitutes about one-half the earth's crust. It is present in most rocks and soils and plays an important part in the physical make up of the soil. Plants require this element to support certain parts of. their structure. The hulls and straws of plant sub- stances are often comparatively rich in this element. Iron is a very common element and in combination it is widely distributed. Although used in small amounts by plants it is nevertheless very important, as it is necessary for the produc- tion and activity of chlorophyll (the green coloring matter of CHEMICAL ElvEMKNTS NEEDED i;V PLANTS 5 plants). The color of soils (red and yellow) are chiefly due to the presence of iron compounds. Chlorine is most commonly found as chloride (common salt). It also occurs in combination with hydrogen, as hydrochloric acid. Magnesium. — This element is found in most rocks and soils in sufficient amounts for the needs of the plant. It is used in different parts of the plant but mainly in the formation of seeds. Sodium. — Chloride is the commonest compoiuid of this ele- ment and is present in conrmon salt, sea water, salt lakes, and in many springs and waters. It occurs in sodium carbonate and sodium nitrate ; the latter compound is a valuable fertilizer be- cause of its nitrogen contc.it. Sodium is believed to be helpful in plant growth. Aluminum. — This element is the most widely distrilmted next to oxygen and silicon of the earth's crust. About one-twelfth of the earth's crust is aluminum. In combination it is found in clay, slate, kaolin, etc. Although it is very abundant it is not used much by plants. Manganese occurs in combination as manganese blend, man- ganese spar, manganite, etc. Plants use this element in small amounts although it is not believed to be necessary for plant growth."" How Plants Feed.' — Every seed is made up of a germ (embryo plant) surrounded by stored up food. When a seed is dropped into the warm soil it germinates and feeds on this stored up food material until it has put forth a root, stem and leaves. It is now able to gather its food from the air, water and soil. On the roots of plants are minute root hairs, composed of single cells, which absorb food materials from the soil water, by means of osmosis or diiTusion. The leaves, on the under sides, have minute openings which permit the breathing of air which con- tains carbonic acid gas. The carbon is used in building up the plant and the excess of oxygen is given back to the atmosphere. This process requires the presence of light as does chlorophyll (green coloring matter of plants). Plants will grow without 1 Much of the remaining portion of this chapter has been taken from Halligan's Elementary Treatise On Stock Feeds and Feeding. 6 FKRTII^ITY AND FERTILIZER HINTS light as lonj^- as the food supply in the seed lasts, hut they will be white and will not produce seed. By the aid of sunlight the materials gathered by the root hairs and leaves are manufactured into com])ounds and retained bv the plants. The Food of the Plant. — The ])lant kee])s growing until it ])ro- duces seed. It may continue its growth for years as is the case with trees. In this continual growing process we cannot see the plant feeding l)ut we know its nourishment is obtained from the soil, water and air. The food of the plant, then, consists of the mineral substances, water and gases taken from the soil and air. Composition of Plants. — All plants are made up of water and dry matter. The water is composed of hydrogen and oxygen while the dry matter contains many elements and combinations of elements. Water.— All plants and parts of plants contain water. The water is present in two forms, namely, physiological and hygro- scopic. 1. Physiological water is that which is contained in the plant structure. It is obtained from the soil. It is used to keep the leaf tissues and their cell walls moist so that carbonic acid gas may be absorbed, to transfer fo(^d materials, and to regulate the temperature of the plant b\" means of evaporation of water, just as the temperature of the animal body is regulated by the evapora- tion of perspiration. When green grass is dried in the sun the loss in weight is mostly due to evaporation of physiological water. 2. Hygroscopic water is that which is taken up from the air and may vary from day to day according to the humiditv of the surrounding air. On rainy days more water would be taken up than on dry days. The writer has often ('etermined the water content of the same samples of corn meal, wheat bran, cotton- seed meal, hays, etc., on different days and found variations often of two per cent. Sometimes there is an increase and at other times a decrease of hygroscopic water, depending upon the humidity of the surn^unding air. The hygroscopic moisture also varies with ditTerent jilant materials. CIIKMICAL ELK-MKNTS NKI'DED i:V I'LAX IS Amounts of Water Used by Plants. — According to Whitson, the ainount of water used by plants varies greatly with the kind of plant and witli climatic conditions, but is always large. For instance, in the growth of one pound of dry matter of corn about 250 to 300 pounds of water are used ; for potatoes, 350 to 400 pounds: fur clover, 300 to 600 pounds. Amounts of Water Exhaled by Plants.^ — One acre exhales Pounds of water Wheat 409,832 Clover 1 ,096,234 Sunflowers 12,585,994 Cabbage 5,049, 194 Grape vines 73^,733 Hops 4,445,021 Variation of Water in Plants. — Some species of plants contain much more water than others and the different parts of the same plant s1k)W a great variation in water content. We have all no doubt noticed that certain fruits like the apple, pear, lemon, plum, peach, strawberry, etc., and roots and tubers as the turnip, beet, radish, carrot, Irish ]iotato, etc., contain a great deal of water. Perhaps some have not heretofore thought that sub- stances like corn grain, wheat kernel, rice kernel, the several grain straws, etc., have water present. The following table gives us the percentage of water in some familiar plants and parts of plants. Apple Grape • Peach Pear Straw her r}- Roots and tubers Beet (mangel) Carrot Irish potato Sweet potato Turnip Forage plants (green) Alfalfa 71.8 Corn I 79.3 Cowpea 83.6 Sorghum | 79.4 Timothy 1 61.6 Cereals and straws Corn (grain) Oats (grain) Rice ( rough ) Rye straw- • • Wheat straw 10.6 1 i.o 10.9 7-1 9.6 StockbridKC, Rock and Soils 8 FERTILITY AND FERTILIZER HINTS Water in Young and Mature Plants. — The percentage of water in young plants is greater than in mature plants. This is easily accounted for because the young plant uses a great deal of water in transferring food materials required for its growth. The Maine State College conducted an investigation on timothy with the following results ■} Water Water Per cent. Per cent. Nearly headed out 78.7 Out of blossom 65.2 In full blossom 71.9 Nearly ripe 63.3 The results on timothy are similar to what would be found with other plants. It follows that the more mature a plant is, the easier it is to field cure. Active cells in plants contain more water than do the older or less active cells and this may account for the larger per- centage of water found in young plants. Dry Matter of Plants. — As previously stated, the plant is made up of water and dry matter. When water is driven off from plants the dry matter is what remains. Now if we burn this dry matter a large proportion of it passes off in the form of invisible gases. This material which so disappears, in burning, is known as organic matter, that which is left is the ash or mineral matter or inorganic matter. The organic imatter is composed of carbon, hydrogen, nitrogen, oxygen, etc. The ash is made up of soda, phosphorus, sulphur, iron, potassium, cal- cium, silicon, etc.* We may express the composition of plants as : Plants ( jy^^^"" ,, (Ash I Dry matter | ^^^^^^.^ ^^^^^^^^. Composition of the Dry Matter of Plants. — A German scientist, Knop, estimated: according to Jordan: "That if all the species of the vegetable kingdom, exclusive of the fungi, were fused into one mass, the ultimate composition of the dry matter of this mix- ture would be the following:" ' Jordan, The Feeding of Animals. CHEMICAL KLKMKNTS NEEOED BY PLANTS 9 Per cent. Carbon 45.0 Oxygen 42.0 Hydrogen 6.5 Nitrogen 1.5 Mineral compounds (ash) 5.0 From the above analysis it is readily seen that carbon and oxygen make up the largest proportion of plants. Let us ex- amine the composition of some farm products that are familiar to us, and find out if this same predominance of carbon and oxygen exists.^ Clover hay 47 Wheat kernel Fodder beets Fodder beet leaves • • Wheat straw Carbon Oxygen Hydrogen Nitrogen Per cent. Per cent. Per cent. Per cent. 47-4 37.8 5.0 2. I 46.1 43-4 5-8 2-3 42.8 43-4 58 1-7 38.1 30.8 5-r 4-5 48.4 38.9 5-3 0.4 Ash Per cent. 7-7 2.4 6.3 21.5 7.0 There is some variation in the composition of these farm products but the carbon and oxygen constitute the largest amounts of the elements present. This predominance of carbon and oxygen is due to the fact that about nineteen-twentieths of the plants' food is obtained from air and water, and the remaining one-twentieth is derived from mineral compounds of the soil and soil water. In other words the farmer only has to supply a small proportion of the elements necessary for producing good crops.* Acids and Bases. — The mineral elements that make up the ash of plants are not present in the free state but in various combi- nations, as acids and bases. The acids and bases of the mineral elements of ash are : ' Jordan, The Feeding of Aninial.s. lO FERTILITY AND FERTILIZER HINTS Acids Sulphuric (hydrogen, sulphur and oxygen) H.JSO4 Hydrochloric (hydrogen and chlorine^ HCl Phosphoric (hydrogen, phosphorus and oxygen ) H,,P.,0^ Carbonic (carbon and oxygen) CO., Silicic (silicon and oxygen) SiO., Bases Lime (calcium and oxygen) CaO Soda (sodium and oxygen) NajO Potash (potassium and oxygen) K^^O Magnesia (magnesium and oxygen) MgO Iron oxide (iron and oxygen) Fe.^O;, The mineral elements do not exist as acids and bases in the ash because in the burning of plant substances there is a re- arrangement of the mineral elements and salts are formed. Salts. — The elements exist in the ash of plants as salts. That is the acids and bases are united and form : Phosphates ] | Calcium Sulphates ^ ] Magnesium Chlorides f *^ ^ Sodium Carbonates j [ Potassium \\'e are all familiar with some of these salts. A few of th>-^ combinations are : Chloride of sodium (common salt) Sulphate of soda (Glauber's salts) Carbonate of lime (limestone) Sulphate of magnesia (Epsom salts) Chloride of potash (muriate of potash ) vSulphate of calcium (gypsum) Carbonate of soda (baking powder) Sulphate of potash (common sul- phate of potash of commerce) Variation of Ash. — The content of ash in diflferent plants and parts of plants varies a great deal as the following table shows: Corn Oats Rice Wheat Roots and tubers (fresh Beet ( mangel ) Carrot Irish potato • Sweet potato Ash Per cent. 1-5 5-5 1.8 I.I i.o i.o 1.0 Oat Rice Rve Wheal Forage plants (hay Alfalfa •• Crimson clover Orchard grass Timothv ■ Ash Per cent. 5-1 7.8 3-2 4-2 7-4 S.6 6.0 4-4 CIIK.MICAL KLKMENTS NEEDKD BY I'LAXTS I I Different parts of the same plant vary in ash content. Corn grain Corn leaves Corn (whole plant) Corn germ Corn stover (whole plant ex cept ears) Corn shucks Corn cob Corn bran Ash Per cent. 4-9 3-4 1.4 1-3 There is also a variation in the amounts of compounds in the ash of different parts of the same plant. The percentages of the compounds in this table are figured on lOO per cent, ash of sugar-cane.^ Potash Soda Lime Magnesia Iron oxide Alumina Silica Phosphoric acid Sulphuric acid- • Carbonic acid - • Chlorine Carbon Ash Ash of leaves Per cent. 31-25 1. 17 5-90 5.II 1.45 1.03 30-32 7-25 11.29 1. 10 3.08 0.16 2.23 Ash of stalk Per cent. 3^23 1.30 5-19 5.76 I-I3 0.25 15.70 5-27 18.47 2.70 4-52 0-54 0.64 Ash of roots Per cent. 17-39 085 3-45 2.61 3.60 4.70 4952 3-99 9.15 0-45 0.98 2 30 1.87 From the figures given in the foregoing tables we find that the leaves of plants contain the most ash. The straws contain more ash than the grains. Let us see the relation of the ash of roots to the leaves of the same plant. Roots Per cent. Ash Leaves Per cent. Ash Sugar-beet 3.83 14. 8S Stock turnip S.oi 11.64 The per cent, of ash in seeds is generally less than in the plant from which they are derived.* ' Bill. 91, Louisiana Experiment Station. 12 FERTILITY .AND FERTILIZER HINTS Sorghum seed Cowpea seed . . Soja bean seed Ash Per cent. 2.1 3-2 4-7 Sorghum fodder. Cowpea ha)' Soja bean hay • . . Ash Per cent. 4.6 7-5 7.2 Occurrence of Mineral Elements in Plants. — According to Forbes;^ Mineral substances of fooclstuffs are present in four mechanical conditions: i. In solution in the plant juices; 2. as crystals in the tissues; 3. as incrustations in cells and 4. in chemical combination with the living substance. The mineral content of any species of plant varies consider- ably as afifected (i) by the composition of the soil and the soil water, (2) by the various factors controlling transpiration of water by the plant and (3) by the loss of mineral substance either through shedding of parts or through the leaching effect of dews and rains. Distribution of Ash in Plants. — Roots and seeds generally con- tain much less ash than leaves because the mineral elements are carried to the leaves for the elaboration (manufacturing) of food and then the water evaporates and the ash remains. The ash present in roots and seeds is usually needed for supporting germination and early growth of the plant, while some of that in the leaves is in excess of what is really needed. Phosphorus and potassium are present in the largest amounts in seeds, followed by magnesia. Silicon and potassium pre- dominate in cereal grasses and straws, and the per cent, of cal- cium is usually larger than phosphorus or magnesium. The leguminous crops (alfalfa, clovers, covvpeas, soy beans, etc.) con- tain more calcium than phosphorus or potassium. Roots and legumes contain much less silicon than straws. Ash of Young and Mature Plants. — According to Wolff the per cent, of ash of the dry matter of wheat, oats, rye, and clover decreases with the growth of the plant. The ash of healthful plants is generally higher in calcium than in sickly plants. The per cent, of calcium and potassium in the ash of grass plants decreases in the growing of the plant and the silicon increases. In the ash of the dry matter of clover, the magnesium and cal- cium increase while the potassium decreases. 1 Bui. 201, Ohio Experiment Station. CHAPTER II. THE FERTILITY OF THE SOIL. The fertility of the soil is shown in the crops produced and a soil is said to be fertile when profitable crops are grown under favorable conditions. Composition of Soils. — In order to understand the conditions which atTect fertility let us become familiar with the composi- tion of soils. Soils are made up of disintegrated (ground) rocks and decayed plant and animal life. Some soils, like sandy soils, predominate in rock particles while peaty soils are rich in decayed plant material. Most soils contain both ground rocks and decayed plants. Inorganic Matter. — That part of the soil composed of ground rocks (sand, silt, clay, etc.) is called inorganic matter and corresponds to some extent to the ash, or non-combustible, or in- organic matter in plants. Of course the particles of inorganic mat- ter in the soil may be different from the original rocks from which they were derived, due to the action of rain, frost, sun, etc., yet we find that a considerable portion of these particles is often of the same composition as the original rocks. Organic Matter. — The decaying vegetable or animal matter in the soil is called organic matter. It is that part of the soil which is driven off when burned and corresponds to the organic matter in plants. Most of the organic matter in soils comes from decaying vegetation. When this decaying vegetable or animal matter becomes thoroughly decomposed it assumes a black waxy consistency and is called humus. This humus is a very im- portant constituent and influences to a great extent the physical and biological condition of soils. The amount of organic matter in soil influences its water hold- ing capacity, texture, temperature, color, supply of available plant food and general productiveness. Factors Influencing Soil Fertility. — There are many factors in- fluencing soil fertility and these may be summed up under the following heads : 14 I'KRTILITV AND FERTILIZER illXTS 1. The available supply of plant food. 2. The physical condition of the soil. 3. The biological condition of the soil. I. The Plant Food Supply. — It may be surprising to know that most farm soils, even those that produce poor crops, are abund- antly supplied with plant food.* Chester of the Delaware Agricultural College, states:^ An average of the results of 49 analyses of the typical soils of the United States showed per acre for the first eight inches of surface, 2,600 pounds of nitrogen, 4.800 pounds of phosphoric acid and 13,400 pountls of potash. The average yield of wheat in the United States is 14 bushels per acre. Such a crop will Plant Food Removkd by Crops in Pounds Per Acre.- Crop Wheat, 20 bu . . . . Straw Total Barley, 40 bu • • • • Straw Total Oats, 50 bu Strpw Total Corn, 65 bu Stalks ^ Total Peas, 30 bu Straw Total Flax, 15 bu Straw Total Meadow hay . . . . Red clover hay • ■ Potatoes, 300 bu. Mangels, 10 tons Gross Weight 1,200 2,oco 1,920 3.000 1,600 3,000 2,200 6,000 1,800 3.500 900 1,800 2,000 4,oco 18,000 20,000 Nitrogen 25 10 35 28 12 40 35 15 50 40 45 85 39 15 54 80 75 Phosphoric acid 12.5 7-5 20 15 5 20 12 6 Potash 7 28 35 8 30 3« 10 35 18 18 14 32 18 7 25 15 3 iS 20 28 40 35 45 15 80 I,inie 8 9 t.5 9-5 1 1 95 21 22 4 38 71 60 75 8 3 19 13 27 16 45 12 66 75 150 50 150 30 ' Bowker, Plant Food. Bui. 47, Minnesota Experiment Statioti. THK FERTILITY OF THE SOIL 15 remove 29.7 pounds of nitrogen, Q.5 pounds of phosphoric acid and 13.7 pounds of potash. Now if all the potential nitrogen, phosphoric acid and potash could he rendered availahle, there is present in such an average soil, in the first eight inches, enough nitrogen to last 90 years, enough phosphoric acid for 500 years and enough potash for i.ooo years. Let us find out the amounts of nitrogen, phosphoric acid, potash and lime removed i)er acre hy some of our leading farm crops. From these figures it is evident that all of the above soils have sufificient amounts of plant food to last for manv years. Corn yielding 65 bushels per acre, only takes away 85 pounds of nitrogen, 32 pounds of phosphoric acid and 95 pounds of potash. Mangels which are heavy users of potash only show a removal of 150 pounds for a ten ton crop. When we compare the amounts of these constituents removed by crops and the total supply in the average soil we may better realize the amount of stored u]) plant food in soils.''' Plant Food not Available. — The question naturally arises, what is the use of adding fertilizers or manure to soils when such large amounts of plant food are present ? The plant food in the soil is dormant ; it is locked uj:) : it is unavailable. Available plant food may be present but the condition of the soil may be such that the plant cannot utilize it. The soil may be acid or sour, or it may contain objcctional)le substances distasteful to plants. The plant obtains its nourishment from the salts in solution in the soil water and these soluble salts constitute the available plant food. The chemist can determine the total plant food, or the, potential fertility, in the soil. Init he cannot tell us how much is available. The available plant food supply may be ascertained, to a certain extent, by carrying on field experiments. The results of such experiments will of course varv with dififer- ent soils and different crops. The chemist can determine whether a soil is acid, alkaline or neutral and from such data advise whether lime would benefit the soil, the amount to applv and the kind of fertilizers to use. Tn such cases a chemical analvsis is i6 FERTIIvITY AND FERTILIZER HINTS exceedingly valuable but ordinarily field trials with crops prove the better way of determining productiveness. The Essential Elements. — In the preceding chapter the elements needed by plants were discussed and the composition of plants given. From the composition of plants aided by field experi- ments it has been possible to learn that certain elements are necessary for plant growth. From this data it has been ascer- tained that only three and sometimes four elements are rec^uired to be furnished the plant for its complete development, as the other elements are fortunately present in sufficient quantities in the air and the soil so that we do not consider them. Nitrogen, (N) phosphorus (phosphoric acid, PioO-) and potassium (potash. KoO) are the elements usually exhausted most readily from the soil, and occasionally calcium (lime, CaO). Because of the necessity of adding nitrogen, phosphoric acid and potash for the growth of most crops, the name "essential" is applied to these elements, and the remaining elements are termed "unessential." The essential elements, nitrogen, phosphoric acid and potash are usually found in larger amounts in plants and in smaller quanti- ties in soils than the other elements. Nitrogen and phosphoric acid are usually more liable to be deficient than potash, and lime is only occasionally lacking. The term fertilizers is applied to materials containing any or all of these essential elements, in available form, and are supposed to make up for the deficiencies in the soil. Fertilizers mav contain other elements as magnesia, sulphuric acid, etc., though needed by the plant are unessential as the soil contains a sufficient amount for crops. The fifteen elements used by plants may be classified as: Elements sometimes lack- Elements obtained from Elements that are pres- in the soil Nitrogen Phosphorus Potassium Calcium (occasionally) the air or water H}-drogen Oxygen Carbon Nitrogen (sometimes) ent usually in suffi- cient amounts Calcium (usually) Iron Sulphur Magnesium Silicon Sodium Chlorine Manganese Aluminium THE FERTILITY OF THE SOIL 17 One Element Cannot Replace Another. — It must be understood that no one of these essential elements can take the place of another, as each has its particular functions to perform which are different for each element. Therefore should a soil be de- ficient in any of these essential elements, the addition of those that are lacking will tend to produce good crops, provided other conditions are favorable. Let us illustrate this by supposing we t'lg. 2. — I, Unfertilized; 2. Potasli, phos. acid, nitrogen; 3, phos. acid, nitrogen. Courtesy German Kali Works. wish to plant a field of corn. We have perhaps plenty of avail- able phosphoric acid, potash and lime for the needs of the corn and the land is in good condition, but the available supply of nitrogen is deficient in the soil. We cannot grow a profitable crop of corn under such conditions because the phosphoric acid, potash and the lime are unable to take the place of the nitrogen, no matter how abundant they may be. Should nitrogen be sup- plied in sufficient amount the crop would be satisfied and should prove profitable, other conditions being right. l8 I'KRTILITV AND FKRTILIZER HINTS It has been found that sodium and potassium may replace each other, to a Hmited extent, in correcting the acidity that may take place in plants, although they cannot replace each other in supplying plant food. There are some elements which have common functions, but each element has its work to perform for the complete development of plants. 2. Physical Condition of the Soil.— There are some soils which contain sufficient amounts of available plant food for the needs of crops but this food cannot be utilized because of other fac- tors which afifect the physical condition of soils. Some of these factors will be briefly discussed. Temperature.- — The temperature of the soil depends upon the heat of the air and the nature of the soil. It is a very important consideration in plant growth.* In summer the sunshine causes the upper soil to be warmer than the lower or deeper soil. In winter the deeper soil is warmer than the surface soil. In other words the temperature of the air affects soil warmth. The germination of seed, the transference of soil water, which contains the available plant food, the movement of the soil air, the development of organisms are all greater when the soil is warm. The coarser soils seem to warm up more readily than the heavy clays. The location of the land influences soil warmth. A soil with a southern exposure is naturally warmer than one with a northern location.* Mechanical Composition. — Should we examine a few different soils we would find that there is a great difference in the size of the particles or grains that make them up. For example, when lumps of different soils are l)roken up and passed through sieves of various sizes, or shaken in bottles with water, parti- cles varying in size from gravel to fine dust are apparent. The grains or particles of soil are usually classified into four groups: gravel, sand, silt and clay. Sandy soils predominate in the larg- est particles, gravel and sand ; alluvial or silt soils contain more particles the size of silt, and clay soils have more of the finest particles, clay. It should be understood that all soils contain large and small particles. A loam soil contains all the particles in about equal proportions.* TIIF: FKRTILITN' Ol" THE SOIL IQ The pcrcentas^cs of moisture, humus and carhonatc of Hme are not inchided in the mechanical analyses of soils. Surface Area of Soil Grains. — The surface area of soil ;^rains varies with the size of the particles. The smaller the grains the more surface area is exposed to the action of water and soil organisms, and the more (piickly is jjlant food rendered available.''' Diameter of grain. Square feet of surface in a pound. Coarse sand i nun 1 1.05 Fine sand, o. i nun. 110.54 Silt, o. 01 mm. 1,105.3s Cla}-, o.ooi mm. 1 1,053.81 Fine clay, 0.0001 mm 1,100,538.16 Lumpy Soils. — The mechanical composition of a soil is im])ort- ant, for the farmer to consider, in order to keep the soil re- ceptive for growing crops. The clustering or lumping of soils is brought about by the adhering of the particles due to the sur- face tension of the films of water surrounding the grains. As the water dries out the grains are held together with the aid of the salts in solution. Fine soils, like clay, contain manv more particles than sandy soils, so it is apparent that clay soils are more apt to form lumps than the coarser soils. Cracking of Soils. — When soils become dry the iilms of water around the soil particles become thinner and the soil contracts, breaking in the weakest point, causing cracks. Puddling of Soils. — If soils are worked when in a very wet condition the soil particles run together and a puddling soil is formed. .After such a soil, especially a clay soil, dries out it becames very hard and most difficult t(^ restore to good condition. A farmer should never work a clay soil when it is too wet. Freezing and Thawing.— AN'hen soils are plowed deeply in the fall and allowed to be acted upon by the frosts a helpful crumb like condition results. The action of frosts is more apparent when northern and southern soils are compared. The northern soils treated as alwve are usually in better tilth than the south- ern soils in sections of little or no frost. Plants are Benefited by Open Soils. — A good tilth of the soil helps the plant a great deal in securing its food, and is therefore an important factor in the production of cro]is. A soil should 20 FERTILITY AND FERTILIZER HINTS be compact enough to support the plant in an upright position, but if it is too compact the young plant has to overcome a great deal of resistance in securing its food. Plants Must Have Room. — Only a certain number of plants can be grown successfully on a given space of land. We have only to examine the root development of mature plants to learn the spreading tendency of plants. If plants are too crowded, im- perfect development is the result. The roots of plants spread somewhat and the distance apart is regulated to some extent by the available plant food, the nature of the plant and the tillage of the soil. In the foreign countries more plants are usually grown on a given area than in America but the land is perhaps more thoroughly tilled, because land is high in price and labor cheapj while in America land is comparatively cheap and labor high. In well tilled soils roots go deeper and do not spread so much as in soils in poor condition. Plants Require Oxygen. — A soil that is too compact will not per- mit of the free circulation of air. When air is excluded from the soil, free oxygen which is absolutely necessary for growth is excluded. It has been shown that when air is not freely sup- plied to plants they become sickly and growth is retarded. When a soil becomes water-logged, plants will not grow and if the condition continues the plants will die. Some plants will grow in water but the water must be fairly free from soil so as to be able to absorb and diiYuse oxygen from the air. It has been found that 40 to 60 per cent, of the water holding capacity of soils is the best amount and 80 per cent, is injurious. Drainage. — Good crops cannot be grown unless the land is well drained, either naturally or artificially. A certain amount of water is essential for crops, but a water-logged condition must be avoided to secure good results. Capillary Water. — In the preceding chapter we learned that crops use a great deal of water, the clover crop for example exhales as much as 1,096,234 pounds per acre. Crops usually rely on capillary water for their supply of this constituent. The upward movement of water in the soil is termed capillary moisture, or capillary water, and is caused by the surface ten- THK FERTILITY OI' THK SOIL 21 sion of the films of water around the soil particles becoming greater as evaporation from the upper surface of the soil takes place. One of the most important problems in farming is to conserve this soil moisture and prevent its evaporation. Amounts of Capillary Water Held by Soils. — Sandy soils hold very little capillary water. After a rain it is estimated that 5 to 10 per cent, by weight of the soil will be water. Sandy loams and silt loams retain 15 to 20 per cent, and heavy clay soils 30 to 50 per cent. Heavy clay soils are suitable for grass lands because of this power of holding" water, as grasses re- quire considerable water for maximum growth. How to Prevent Loss of Capillary Water. — As capillary water is so important for the welfare of crops we should learn how to prevent its loss. Water will follow along the path of least resistance. So if we form a soil mulch by cultivating or stirring the soil to the depth of two or three inches we will offer re- sistance to the upward movement of water. The soil should not be cultivated too deeply because some of the small roots are lia- ble to be injured. How to Increase the Upward Movement of Capillary Moisture. — When seeds are planted in dry seasons it is often advisable to bring up the water to aid in their germination. This may be ac- complished by rolling the soil thus making it firmer. After rolling it is important to form a soil mulch again to prevent the loss of all the water. =*' 3. The Biological Condition of the Soil. — All culti^•ated produc- tive soils are full of organisms, both animal and vegetable, which aid in furnishing plant food. There are many different organ- isms whose functions vary a great deal. Most of these organ- isms are so small that they cannot be seen without the aid of the microscope, while some, with which we are all familiar, are large. The rodents, worms and insects all have their place in stirring the soil although the rodents and some of the insects are in- jurious to crops. Plant roots are beneficial in that they leave organic matter in the soil and openings for the access of water and air. 22 FKRTILITV AXl) FKRTILIZF.R HINTS The organisms we are most interested in are the hacteria (minnte plants) hecause of their beneficial effect in crop ]iro- (hiction. The number of bacteria in the soil depends upon its physical condition. Water-logged soils, sandy soils, acid soils, and soils low in organic matter contain very few and sometimes no bac- teria. Soils rich in humus, contain sometimes as high as loo,- 000,000 bacteria per gram,^ while the average well cultivated soil contains 1,000.000 to 5,000,000 per gram. The cold w'inters of the north decrease the number of bacteria but these multiply during spring" and summer.* Nitrification. — Certain bacteria have the power of converting the organic nitrogen present in animal and vegetable matter into ammonia. No doubt you are all familiar with the ammonia smell around fermenting manure. This is the result of the action of bacteria. The same action that takes place in the manure heap occurs in the soil when organic matter is present. When the ammonia is formed another kind of bacteria seizes it and changes the ammonia into nitrous acid or nitrites, and this latter compound is in turn attacked by another organism and con- verted into nitric acid or nitrates. In this latter form it is readi- ly dissolved by the soil water and available as plant food. There is a continual cycle of the forms of nitrogen. The plant uses the nitrogen in the form of nitrates, converts it into organic nitrogen, and wdien the plant dies it may be returned t(^ the soil to go through the same process again. ^lanure or other organic matter hel])s nitrification."' Keeping the soil well open so that a liberal supply of air may permeate it has a beneficial effect on nitrification. The more porous the soil the deeper nitrification occurs. Denitrification. — There are some bacteria that set free nitrogen. These bacteria exert -a reducing action rather than an oxidizing one. Some reduce nitrates (nitric acid) to nitrites (nitrous oxide) and ammonia. Others reduce nitrates to nitrites and then to free gaseous nitrogen. It has been found that there are more 1 One ounce 28. 35 grams. THE I'HR'niJTV OP THE SOIL 23 denitrifying organisms than nitrifying bacteria, although the loss of nitrogen from well drained and tilled soils is not large, because the denitrifying bacteria cannot attack the nitrogen in such soils. The nitrogen wasting bacteria work considerable damage in manure heaps. Organisms that Gather Nitrogen. — Other organisms found in the soil that exert an eiTect on its fertility are those that live in the tubercles or nodules on the roots of certain plants called the legumes, of which cowpea, bean, pea, clovers, alfalfa, vetch, etc., are examples. These plants through the action of these bacteria have the power of acquiring the free gaseous nitrogen from the air and utilizing it in their growth. The bacteria se- cure this free nitrogen from the air in the soil and the plant acc|uires it from the bacteria. When the plant dies the nitrogen left in the roots remains in the soil and thus enriches it. The particular bacterium can only attach itself to the legume it is suitable to. That is, bacteria forming tubercles on the roots of clover will not grow on cowpea roots. When there is a plenti- ful supply of nitrogen as nitrates in the soil the legumes will not always form tubercles and utilize the free atmospheric ni- trogen, but will gather their supplv from the soil. I^egumes therefore are able to secure nitrogen from the soil and the air. The tubercles seem to form better in alkaline soils containing lime. Inoculation of the Soil. — The absence of tubercles on the roots of legumes may therefore be due to the absence of the particu- lar bacteria required, to the excess of nitrates, or to the acidity of the soil. Should the soil be deficient in the particular bac- teria needed, the soil should be inoculated. This inoculation is accomplished by sowing soil from a neighboring field that has produced a good crop of the kind desired, or if such a soil can- not be obtained, by inoculating the seed before planting with a pure culture which has been obtained from the tubercles of the kind of crop to be raised. These cultures may be obtained from the United States Department of Agriculture and dealers in seeds. In using soil from another field for inoculating, fungus diseases, 3 24 FliRTIIvITY AND FERTILIZER HINTS insects and objectionable weeds are often introduced which be- come a serious menace in the production of crops. Care must be taken to secure soil from a disease free field. The pure cultures are not always satisfactory, as they are hard to preserve in transportation, so that the use of soil is perhaps the better method just now. CHAPTER III. MAINTAINING SOIL FERTILITY. As the fertilizer ingredients nitrogen, phosphoric acid and potash are the plant food elements that have to be supplied, let us find out some of the ways they are taken away from the soil and methods of preventing and restoring their loss. Erosion is the loss of soil by the action of water or wind. Any one who has ever lived in the South is familiar with the tremendous losses of fertility incurred by erosion. The most serious losses occur on hilly clay soils. Cotton and corn are grown on many of the southern soils year after year and the soil is left bare during the winter. These soils are not plowed very deep and when a heavy rain comes only a small amount of the water can soak into the soil. If the land is hilly the rain forms little rills at first which finally become gullies and much of the good fertile soil is washed to the valleys or bottom lands. It a few seasons a great deal of such hill land becomes unpro- ductive. There are other sections in America besides the South where erosion is damaging farms. In some of the far western states and other sections where the land is hilly, erosion is a source of loss of fertility. Erosion by water besides carrying away the most fertile part of the soil puts the land in such a condition that it is difficult to operate. Gullies are objectionable in growing crops. On light sandy soils the blowing away of the surface soil by wind often results in serious losses of fertility. Mounds or ridges are often formed which interfere with cultivating the soil. Ways to Check Erosion. — Plowing up and down hill is very l)ad practice as the furrows become regular waterways during a rain storm. In the South the lands that are subject to erosion are usually the clay soils which will not absorb water readily. Shallow plowing is practiced and deep plowing will cause more water to be absorbed and retained. Most of these soils are lack- ing in organic matter. By growing green crops in the winter 26 FERTILITY AND FERTILIZER HINTS and turning them under in time for the summer crops, erosion will be stopped considerably during the winter and much organic matter will be supplied which will make clay soils more porous and spongy. Underdrainage prevents erosion by carrying the excess of water away gently. Many farmers terrace their soil to prevent it from washing away. This custom is not as beneficial as deep plowing, plow- ing under of green crops, or putting the land in pasture. Many of the most successful farmers keep their rows level so when it rains the water remains in the furrows instead of washing down hill. These furrows will not be straight but answer the purpose of saving fertility. Drainage. — The loss of fertility by drainage is chiefly concerned in the loss of nitrogen. This element to be favorable for most plants to assimilate must be in the form of nitrates which are readily soluble in water. Phosphoric acid and potash are fixed in the soil so that they are insoluble in water and hence very inappreciable amounts are lost by drainage.* Experiments have shown that the loss of nitrogen by drain- age is greater on soils that are idle than on cultivated soils. At first thought one would suppose that the loss would be greater on the cultivated soils as they are more open and porous, and hence permit of a more free passage of water through the soil. The excess of nitrates in cultivated soils is carried down in the soil but after a rain the capillary water carries it up again to the plant roots. Again, the plants are continually using up the available supply of nitrogen as fast as it is formed so that there is no appreciable excess to be carried away. It has been found that about 37 pounds of nitrogen per acre are lost from average idle land during a year. This loss of ni- trogen is quite large when we consider that 20 bushels of wheat, not counting the straw, remove 25 pounds of nitrogen ; 50 bush- els of oats, 35 pounds ; and 65 bushels of corn, 40 pounds.* Fallowing. — In the arid sections of this country where dry farming is followed it is often necessary to let the land remain idle for a season to conserve enough moisture to produce profit- MAINTAINING SOII^ FERTIUTY 2/ able crops. The land is usually plowed two or three times, at intervals, or plowed once and harrowed two or three times. This procedure keeps down the weeds and increases the moisture in the soil. According to King, 203 tons more water was found on fallowed land per acre in the spring following the fallow, than on land that was not fallowed, and 179 tons more water was found on the fallowed field after a crop was harvested than on the other field. ^ Fallowing increases the supply of available nitrogen as ni- trates and in some sections fallowing is practiced for this reason. The yield of the crop following fallowing is increased but con- siderable humus is lost by being oxidized, and generally more nitrates are formed than can be used up by the crop following fallowing. Snyder has found by experiments that 590 pounds of nitrogen per acre were lost by two years of summer fallow- ing, or an amount sufiicient for five wheat crops." At the Roth- amstead Experiment Station experiments show that considerable more nitrogen was lost from bare soils than from wheat land.* On rich soils the losses are greater than on soils deficient in organic matter because the oxidation of humus is more rapid. It is evident, then, that fallowing increases the pnxluction of crops at the expense of a reduction of humus. In sections of plentiful rainfall, fallowing is often injurious and it should only be practiced in the dry sections where there is not enough rainfall to carry away the nitrates and therefore not sufficient moisture for the continuous growing of crops. Other Ways Nitrogen is lost. — The washing away of nitrogen as nitrates is not the only way this element is lost, but con- siderable of this valuable constituent escapes in the form of gases. This loss as gas is occasioned by denitrification, which reduces the nitrates to gases, and the liberation of nitrogen from organic matter. The loss on soils rich in organic matter is greater than on poor soils. Experiments show that in continuous cropping more nitrogen 1 Roberts, The FerUlity of the Soil. " Snvder, Soils and Fertilizers. 28 FKRTILITV AND FERTILIZER HINTS is usually lost than the crop removes. The following table il- lustrates this point. ^ Loss OF Nitrogen by Continuous Cropping Per Acre Per Year. Name of Crop. Wheal Corn . . Oats . . Barley Nitrogen removed by crop. Pounds. Nitrogen lost by other means. Pounds. 24-5 56 46 30 146.5 29 150 170 Total nitrogen re- moved and lost. Pounds. 171 85 196 2uO The loss of nitrogen by continuous cropping of cotton, corn, tobacco and the cereal crops is a very serious one. Loss of Phosphoric Acid and Potash. — Although phosphoric acid and potash are usually present in the soil as compounds insolu- ble in water, nevertheless large quantities are lost every year by being carried away with the soil into rivers and other streams. Again, traces of phosphoric acid and potash are carried away in the soluble form by drainage and although this loss is not large per acre it amounts to a great deal in the course of time. The Mississippi River deposits in the Gulf of Mexico 3,702,- 758,400 cubic feet of solid material per year. One cubic foot of this solid material weighs about 80 pounds. This material is quite rich in potash often containing as high as 0.50 per cent, of this constituent. The phosphoric acid content is much lower than this figure but is considerable. The rivers that empty into the oceans in the northern part of the United States do not perhaps carry away so much fertility as the rivers of the far south, but the annual loss of the mineral elements carried away in streams is appalling. One Crop Farming. — The exclusive growing of one crop caused more farms to be abandoned in the United States than any other practice. The continuous croi:)ping of wheat in the West, to- bacco in Kentucky. A'irginia and North Carolina, cotton in the South, and corn in the North Central States has always re- sulted in the loss of fertility and depletion of the soil. All of these crops with the exception of corn are sold from the farm ' Bill. s> Minnesota Hxperiment Station. MAINTAINING SOIL FERTILITY 29 without the return of any fertiHty. On most of these one crop farms no fertihty is put on the soil and the farm is abandoned or else artificial (commercial) fertilizers are used. Most of our soils in the United States were formerly fertile but the prac- tice of growing crops without returning organic matter has re- sulted in decreasing the yields on our older cultivated lands. Under the subject "fallowing" we learned that it was poor pro- cedure to allow the land to lie idle except in dry regions, and the best farmers to-day are those that utilize their land con- tinually and to the fullest extent. When we visit some of the European countries wdiere land has l)een in cultivation for cen- turies, we find that these lands are still producing valuable crops, and that the yields are as large, if not larger now, than they were two centuries ago. This condition exists in Europe because fertility has been returned to the soil every year to sustain crops. Fortunately, land has been comparatively cheap in the United States and when a farm failed to produce paying crops another piece of land was secured, and so on. The time has arrived when the acquiring of new land for one crop farming is hard to obtain at a price within the bounds of such farmers. So it is now necessary and more profitable for the farmer to grow other crops in conjunction with his money crop. This growing of other crops is called diversifying or rotating". Diversification and Rotation of Crops. — Diversification is the growing of diiTerent crops without any regular or definite sys- tem. Rotation of crops is .--pokcn of as growing a certain num- ber of crops, in regular order, on the same piece of land. For example, a rotation may consist of four crops, corn, oats, wheat and clover, and will be called a four year rotation because these crops will be grown in order on the same piece of land and take four years to complete. A farmer may have 160 acres in his rotation and each year 40 acres will be allowed for each of the four crops mentioned. Each 40 acres will grow the same crop every fifth year and one of the crops every year. The terms six-year, five-year, four-year, three-year, two-year, etc., are applied to rotations depending upon the time it takes to complete them. Rotations taking 15 years to complete are known 30 FERTILITY AND FERTILIZER HINTS in Europe but the short rotations of three to six years are found to be profitable in the United States. Make up of a Rotation. — The crops used in rotations are nat- urally selected according to the location, nature of the soil, avail- able crops, market prices, kind of farming, insect and plant dis- eases, climate, etc. A stock farm would require different crops than a tobacco farm; a dairy farm in Wisconsin could not probably use the same rotation as a dairy farm in Alabama; two farms in the same state with different soil conditions would perhaps se- lect different crops for a rotation ; a farm ten miles from a market would no doubt find it more practical to grow different crops than one i,ooo miles away; and crops would not be chosen that insects or plant diseases ruin. Reasons for Rotating- Crops. — Some of the reasons for rotating crops are : 1. To keep down weeds. 2. To gather nitrogen from the air. 3. To distribute farm labor more evenly. 4. To eradicate insect or other diseases. 5. To furnish feed for live stock. 6. To give the farmer a regular income. 7. To prevent losses of fertility. 8. To utilize plant food more evenly. 9. To include deep and shallow rooted plants. 10. To save fertilizer expenditure. 11. To regulate the humus supply. 12. To conserve moisture in dry sections. I. Rotation of Crops Keeps Down Weeds. — It is well known that the growing of particular crops is accompanied by certain weeds. Those crops that are sown broadcast, as the small grains, are more apt to be weedy than cultivated crops as corn, cotton, tobacco, potatoes, etc. When crops like wheat, hay, etc.. are grown continuously the yields or the quality of the crops are often materially reduced by weeds. Intertilled crops as corn, to- bacco, cotton, potatoes, etc., when well cultivated, are known as "cleaning crops." So in planning a rotation crops should be MAINTAINING SOIL FERTILITY 3 1 selected that will tend to keep down weeds. Cultivated crops should be included with those that are sown broadcast. 2. Legumes are Profitable. — By including legumes as clovers, Canada field pea, cowpea, velvet bean, soy bean, etc., in a rotation, it is possible to gather considerable nitrogen, which is the most expensive fertilizing element to buy, from the air. A crop of red clover, one year old, is estimated to contain 20 to 30 pounds of nitrogen in the roots, per acre. A crop of cowpeas in Louis- iana furnishes 100 pounds of nitrogen per acre. By plowing under leguminous crops enough nitrogen is often furnished so that the following crop does not require any extra supply, and if some nitrogen has to be supplied, that amount is much less than it would be were not nitrogen gathering crops utilized. The Minnesota Experiment Station^ found a loss of 2,000 pounds of nitrogen per acre when wheat, barley, corn and oats were grown for twelve consecutive years ; two-thirds to three- fourths of this amount was not used by the crops but was lost in other ways. The Ohio Experiment station- found that there was a gain of 300 pounds of nitrogen per acre in excess of what the crop utilized when clover was included in five-year rotations, covering periods of ten years. When timothy and non-legumes were used in place of clover, nitrogen was lost from the soil ; the loss of nitrogen from the soil was a little more than that removed by the crop. 3. The Distribution of Farm Labor. — One of the most important points in favor of a rotation of crops is that it allows of a more even distribution of farm labor. When several crops are grown every year the farmer is able to employ help the greater part of the year and thus secure more efficient labor at a less cost for the work performed than should single crop farming be in vogue. 4. The Checking or Eradication of Insects and Plant Diseases. — Many times crops become so badly attacked ]:)y insects, or in- fested with plant diseases, that there are no profits and often large losses in trying to produce them on the same field con- 1 Bul.Sg. « Bui. no. 32 FKRTILITY AND FERTILIZER HINTS tinually. A rotation of crops often eliminates such troubles be- cause certain insects and plant diseases are only common to one particular crop. A good illustration of this is noticeable in the growing of cotton. There is an insect called the cotton boll weevil, which punctures cotton bolls and destroys the crop. Fields that once produced valuable crops of cotton must now be planted to other crops which are not injured by this insect. 5. Rotation Furnishes Feed for Live-stock. — One crop farmers are often forced to buy feed for their live-stock. A farmer who uses a rotation of crops can ]3lan his rotation so that most of the feed will always l>e produced on the farm. In one crop Fig. 3 — Oats fit well in rotations and furnish feed for live-stock. farming the sale of the crop brings only one value. When several crops are grown it is possible to produce feed for live- stock and a double value is received for the crop. This double value is represented in the feeding value and fertilizing value ; the crop is fed and the manure spread on the land. 6. A Regular Income. — Farmers who raise single crops receive their money but once a year and many of these farmers use MAINTAINING SOIL FERTILITY 7,^ their crops in paying the inerchant for the last year's suppHes. They often hve from year to year on the credit basis and pay much more for their supphes than the farmer who is able to pay for what he gets in cash. In certain sections of this coun- try this credit system of farming has proved disastrous because one or two bad years caused the loss of the farm. The single crop farmer generally has to buy more supplies than the farmer who grows several crops. The farmer who practices rotation has crops to sell at different times in the year and so has a more regular income than the single crop farmer who gets his money but once a year. 7. Preventing Losses of Fertility. — The farmer who rotates his crops may sell the crop tliat removes the least fertility from the soil and if the money crops remove a great deal of fertility, he may regulate his rotation so as to restore this loss cheaply. 8. A rotation of crops utilizes plant food more evenly than when single crops are continually grown. Corn, wheat and other grain crops use a great deal of nitrogen and phosphoric acid while tobacco and potatoes are heavy potash feeders. By the proper selection of crops forming rotation, the plant food may be drawn on more evenlv and losses of fertility prevented through leach- ing, etc. 9. Deep and Shallow Rooted Plants. — A rotation of crops has an advantage over single crop farming because of the variation in depth of root systems of different crops. Alfalfa and corn have deep tap roots and obtain food from the subsoil, while oats, timothy, blue grass, rye, etc., have shallow roots and feed from the upper soil. By alternating deep and shallow rooted plants the fertility from the subsoil and surface soil is more evenly utilized. Often the surface soil may predominate in ni- trogen and phosphoric acid and the subsoil in potash and lime. When the fertility is thus distributed the alternating of shallow and deep rooted plants is important as the fertility of the subsoil is brought to the surface soil by the decay of roots. Another advantage of growing deep and shallow rooted plants is the improvement of the physical condition of the soil. Deep rooted plants tend to make a soil more porous because the de- 34 FERTILITY AND FERTILIZER HINTS cay of roots leaves passages in the soil wh'ich aid in draining and aerating it. Grass crops tend to make a soil compact, while al- falfa, roots, grains and other cultivated crops tend to open up the soil. A rotation should be selected to keep the soil in good physi- cal condition. Sandy soils are improved by crops that compact them while clay soils should be made more porous. 10. Rotation Saves Fertilizer Expenditure. — On some farms that formerly used 150 to 300 pounds of commercial fertilizer per acre, as high as 1,500 to 2,000 pounds must be used now to give the same yields. A proper rotation of crops will save the em- ployment of such large quantities of commercial fertilizers. Farm manure may be used and commercial fertilizer only applied to those crops that are most in need of nourishment. 11. Rotation of Crops Regulates the Humus Supply. — Some crops furnish humus while others tend to deplete the soil of this material. Single crop farming is very exhaustive on the humus supply of the soil while a rotation of crops should be selected to conserve the humus content of a soil. Grass crops tend to increase the humus supply, wdiile grain, cotton, tobacco, etc., have the opposite effect of consuming humus. The addition of farm manure is helpful in supplying humus.* 12. A Rotation of Crops Conserves Moisture. — In the arid regions the conservation of moisture is an important considera- tion in planning a rotation. Heavy moisture consuming crops should not be planted in succession in sections of small rainfall, but heavy consuming and light consuming moisture crops should be so grown as to conserve the moisture supply.* System of Farming. — The loss of fertility sold from the farm depends upon the kinds of crops produced and sold. When live-stock, butter and milk are sold there is less fertility lost than from common farm crops.* CHAPTER IV. FARM MANURES. Farm manure has been used for centurit's in restoring fer- tility to the soil. It is the oldest and one of the most important of our fertilizers. It is formed from vegetable and animal sub- stances and naturally should prove of great value. In some sec- tion of this country farm manure is wasted, but the value of this material is generally becoming better understood and is more carefully saved than formerly, especially in the older farming regions. Kinds of Manure. — When there is a great deal of straw or hay in manure, it is said to be coarse. It is termed stable manure when it is accumulated in stables and contains all the solid and liquid portions. Barnyard manure is a name applied to manure which is subject to exposure of rains and sun and may be com- posed of pure solid excrement, or excrement and bedding. Conditions Affecting the Value of Manure. — There are many conditions which affect the value of manure. 1. The age of the animal. 2. The use of the animal. 3. The kind and amount of bedding used. 4. The kind of animal. 5. The nature and amount of feed used. 6. The care, preservation and use of the manure. 1. The age of the animal iniluences the value of manure. Ma- nure from young animals is not so rich in the fertilizer constitu- ents, nitrogen, phos])horic acid and potash as that from mature animals, even when the same kinrl of feed is used. Young ani- mals require and retain nitrogen and phosphoric acid for growth, while mature animals use these constituents for maintaining the functions of the body and for repairing broken down tissues, after which they are cast off in the manure. 2. The use of the animal influences the value of manure. Milch cows return less of the fertilizing constituents in the feed than other domestic farm animals. Fattening pigs return less than 36 FERTILITY AND FERTILIZER HINTS fattening sheep and fattening sheep less than fattening oxen. Horses return the same relative amounts from the feed whether at work or at rest.* 3. The Kind and Amount of Bedding Used, — Bedding besides afifecting the value of manure renders stables more sanitary. It provides comfort for the animal, makes the manure lighter and easier to handle, absorbs the liquids, lessens fermentation and improves the texture of the manure. Straw is the most common bedding used and is well suited for this purpose, because it is largely made up of cellulose which is a good absorber on account of its hollow structure.* There is a difference in the composition of straws, but they all contain a high potash content. The nitrogen and phosphoric acid are rather low and when large amounts of straw are employed the fertilizing value of the manure is naturally lowered. Leaves, — Dried autumn leaves are often gathered and used as bedding. They are not as valuable as straw as they do not fer- ment very rapidly and are liable to cause acidity in the manure. Sawdust is often used as bedding and it is much inferior to straw and dried leaves from a fertility standpoint. It decom- poses very slowly in the soil. However, this material is a good absorber of the liquid portions and makes a good bedding when it can be obtained cheaply. Shavings are sometimes used as bedding and possess about the same properties as sawdust. Peat when dried is a good material to use in stables as it is an excellent absorber. It absorbs not only the liquid portions of the manure but also the nitrogen gases evolved, and renders the stable free from foul odor. It in itself contains considerable organic matter which is beneficial and it is readily fermented in the soil. It is a good material to use in conjunction with straw. The use of peat as bedding increases the nitrogen content of the manure. The nitrogen percentage in peat varies a great deal but it usually approximates i to 1.5 per cent. Absorptive Power of Bedding, — According to Snyder,' the ab- sorptive power of different kinds of bedding are : ' Soils and Fertilizers. FARM MANURES 37 Per cent, of water absorbed. Fine cut straw 30.0 Coarse uncut straw 18.0 Peat 60.0 Sawdust 45.0 Snyder says : "The proportion of absorbents in manure ranges from a fifth to a third of the total weight of the manure." The following experiment shows the absorptive power of straw and peat in two similar stables carrying the same stock, in one of which straw was used and the other peat. Ammonia in Stable Per Million of Air.' Litter I.St day 2d day .^d day 4th day 5th day 6th day 7th day Straw .0012 .0028 .0045 .0081 ■0153 trace .0168 .001 Peat moss .017 4. The Kind of Manure. — Manure from different kinds of ani- mals varies in value. Horse Manure. — The manure voided by the horse is rich in nitrogen and not so finely divided as the manure from cows, sheep, etc. This is due to the horse only having one compart- ment in its stomach and therefore the feed, especially coarse feed as hay, etc., is less broken up and digested. Horse manure is generally comparatively dry and hard to incorporate with bed- ding. On this account, and because of its coarse nature and chemical composition, fermentation readily sets in and consid- erable nitrogen is lost unless the fermentation is stopped. When fermentation is allowed to continue the value of horse manure is very much decreased. Boussingault found by experiment that when fermentation was allowed to continue, one-half of the nitro- gen was lost from the fresh manure.* The liquid portion of horse manure contains a great deal more nitrogen that the solid. The liquid portion of horse manure contains very little phosphoric acid. Cow manure is much colder than horse manure and so a fine combination results when it is mixed with horse manure ; the ' Hall, Fertilizers and Manures. 38 FERTlIvITY AND FERTILIZER HINTS fermentation of the horse manure is stopped and the nitrogen saved, and the mixture is better than cow manure alone. Cow manure contains more water than horse manure due perhaps to the large amount of water drank by this class of animal. Cow manure does not ferment rapidly and when dry decomposes very slowly in the soil. It is estimated that 6 to 10 pounds of straw are necessary to absorb cow manure, depending upon the amount of liquids voided. The nitrogen content is present in greatest amount in the liquids while there is little phosphoric acid present in this portion of cow manure. Hog Manure. — The composition of hog manure is quite variable depending upon the feed consumed. When tankage and other highly nitrogenous feeds are employed the manure is rich, but when feeds containing small amounts of fertilizing constituents are used, the manure is not so valuable. Hog manure contains a high percentage of water and is slow to decompose. It is es- timated that 4 to 8 pounds of straw are adequate for absorbing pig manure. The liquid portion of hog manure contains more phosphoric acid and the solids more potash than horse or cow manure. As previously mentioned, the nitrogen content of the liquid por- tion of hog manure depends upon the nature of the feed. Some- times the nitrogen will reach 1.5 per cent, in the liquid portion. The liquid portion is higher in water than manure from other farm live-stock. Sheep Manure. — The manure from sheep is more valuable than that from other farm animals. On account of its being dry and rich in nitrogen it ferments rapidly although not so quickly as horse manure. The slower action is perhaps due to its more compact mechanical condition. Losses of nitrogen in sheep ma- nure are apt to occur unless the manure is well taken care of. Both the solids and liquids of sheep manure run higher in nitro- gen that the manure from other farm animals, and the water con- tent is lower. The phosphoric acid content of the solids is also high and that of the liquids appreciable.* FARM MAM'RKS 39 Hen manure contains its nitrogen in a quickly available form and unless carefully preserved fermentation sets in and drives ofif considerable of this valuable constituent as ammonia. Lime should not be used where the manure is kept as it hastens the Hberation of ammonia. The per cent, of nitrogen in hen manure depends a great deal on the kind of feed consumed. Hens pro- duce, per i.ooo pounds live weight, about 35 pounds of manure per day, and about one bushel of manure is produced by a hen per year. Hen manure approximates sheep manure in compo- sition. It is a valuable manure l)ecause it acts quickly.* Analyses of Farm Manures.' Kind of maiuire Water Per cent. Nitrogen Per cent. Potash Per cent. Phosphoric acid Per cent. Cattle (solid fresh excrement) Cattle (fresh urine) Hen manure ( fresh ) Horse (solid fresh excrement ) 73-27 0.29 0. s8 1.63 0.44 1-55 0.55 1-95 0.50 0.60 0.43 0.10 0.49 0.85 "-35 1.50 0.15 2.26 0.60 0.13 0.83 0.17 1-54 0.17 Sheep (solid fresh excrement) 0.31 O.OI Stable manure (mixed ) Swine (solid fresh excrement ) 0.30 0.41 0.07 How to Calculate the Amount of Manure Produced.— A method used for determining the amount of manure produced by ani- mals is to multiply the amount of dry matter in the feed con- sumed bv 2-^ for ^ cow, 2.1 for a horse and 1.8 for a sheep. A horse that consumes feed containing 25 pounds of dry matter per day would void 25 X 2.1 = 52.5 pounds of manure a day. Add to this the amount of bedding used and you will arrive at the total amount of mamn-e. 5. The nature and amount of feed used afifects the value of the manure. The richer the feed the higher the fertilizing value of the manure. Coarse feeds like hay, straw, etc., produce less valuable manure than concentrated feeds like linseed meal, gluten meal, cotton-seed meal, etc.* ' Fletcher, Soils. 4 40 I-ERTILITV AND FERTILIZER HINTS Lasting Effect of Manure. — The lasting effect of manure is shown by the experiments conducted at Rothamstead. A plot of grass land received applications of 14 tons of manure per acre for 8 consecutive years and then the applications were discontin- ued. During the first year after the discontinuance of manure the yield was twice that of an unmanured plot. Since that time the yield on the manured plot has slowly decreased until at the end of 40 years the excess has been about 15 per cent, greater than the yield of the unmanured plot. An experiment was conducted with barley. Three plots were employed. One plot received 14 tons of manure per acre since 1852, another received 14 tons of manure per acre for 20 years and then the applications were stopped, and the third has been unmanured since 1852. The experiment showed that the continuously manured plot had the largest yields but the plot that was measured for 20 years is still producing crops at least 40 per cent, greater than the unmaimred plot. The results in these experiments would not be found to be so apparent in actual farming, as the soils that were used for these experiments were more exhausted than the farmer would use. However, the results are interesting as they .show the almost permanent effect of farm manure on soils." 6, The Care, Preservation and Use of Manure. — From the fore- going pages it is very evident that the comppsition of manure and the amounts produced by dift'erent kinds of animals are ex- ceedingly variable. It is also known that a regular value for this product cannot be estimated from its chemical composition. "Waste of Manure. — In some sections of the United States farm manure is dumped into streams, burned, buried in holes in the ground, or allowed to remain in large piles in some uncultivated place. The soils in many of such sections are fertile enough to produce profitable crops but it seems very wasteful to throw away such valuable fertilizer. Leaching. — When a manure heap is exposed to the washing of rain and the solutions allowed to wash away, the value of the manure is decreased. The soluble plant food elements are washed FARM MANURES 41 away togetlier with more or less of the manure itself. Leaching is one of the most important subjects to consider in the care and preservation of manure because it is the source of one of the greatest losses in this valuable product. Experiments have been conducted to show the g-reat losses that occur bv leaching. Horse Fig. /(. —The manure from live-stock sliou'.d be carefully saved. manure suffers larger losses than mixed horse and cow manure, or cow manure.* Fermentations. — There are certain bacteria that produce fer- mentations in manure piles and liberate nitrogen as gas causing large losses in manure. These fermentations are brought about by two classes of organi.sms ; aerobic bacteria and anaerobic bac- teria. I. The aerobic bacteria require oxygen to be active and the anaerobic bacteria are only active in the absence of oxygen. On the outside of manure heaps where air circulates, the aerobic bacteria work while in the interior of the heaps where no air 42 FERTILITY AND FERTILIZER HINTS can penetrate the anaerobic fermentation takes place. The aerobic bacteria convert the nitrogen present in the organic matter of the manure, into ammonia, in which form it passes off into the atmosphere. Because of the great amount of carbon dioxide formed during this action some of the ammonia is converted into carbonate of ammonia which is also volatile. 2. The anaerobic bacteria convert ammonia salts to nitrogen. Some of these bacteria have the power of reducing nitrates to nitrites, and to ammonia. The anaerobic bacteria do not bring about such losses as the aerobic bacteria, so it is important to keep the manure heap well compacted to prevent the action of the aerobic organisms. Keep the Manure Moist. — Dry manure ferments more readily than wet manure. To prevent active fermentation the manure heap should be kept moist. It is not necessary to add enough water to leach it. Water excludes the air and promote anaerobic action which is beneficial.* The temperature in fermenting horse, sheep and poultry ma- nure often goes higher than 150° Fahrenheit (65° Centigrade). The highest temperature is usually near the surface as the fer- mentation is most active there. Composting manure is helpful in increasing the availability of that plant food. It also kills many weed seeds. There is less loss of plant food when the manure is applied to the soil fresh, than when allowed to rot. It is not generally convenient to haul the manure from the stable to the land as other work is of more importance, so that the manure has to be stored until the regular farm work becomes slack. When manure is com- posted it should be kept compact and moist and the heap should be shaped to shed water. A layer of earth on the top of the manure compost will tend to absorb some of the gases. Voelcker^ gives the following as the composition of fresh and rotted manure. I Ivyon and Fippin, Soils. Farm manures 43 Water Soluble organic matter. . . • Soluble organic nitrogen- • Soluble inorganic matter. • Insoluble organic matter- . Insoluble inorganic matter Fresh Rotted Per cent. Per cent. 66.17 75-42 2.48 3-71 0.15 0.30 1-54 1.47 2576 12.82 4.05 6.58 It is seen that manure that is composted contains the fertilizer elements in a more available form than in fresh manure. The organic matter is decreased by allowing manure to rot. Snyder^ says : ''A ton of composted manure is obtained from 2,800 pounds of stable manure." There are of course some losses of nitrogen in composting manure, the extent of these losses depending upon the compactness and dryness of the ma- nure. The principal benefits derived from composting manure are ; the improvement of the physical condition, and decomposition takes place in the manure that ordinarily would have to be performed in the soil. Sometimes manure is composted with earth, sod, leaves and wastes from the farm. Store Manure Under Cover. — Whenever manure is left out of doors exposed to the rain losses occur. Many farmers preserve manure in different w'ays. Some use covered yards where the stock are allowed to exercise and the manure is kept compact by the tramping of the animals. In this practice bedding should be used to absorb all of the liquids and to allow the animals to be comfortable. The site should be well drained and kept dry. The manure from sheep, hogs, young stock, etc., is often preserved in this way. Some farmers keep the manure in cel- lars under the stable. The fermentation of manure in the cellar of a stable is liable to produce foul odors and is especially ob- jectionable in dairy barns. Another method of storing ina- nure that is used in the older farming sections, especially in dairies, is to build covered cement pits just outside the barn and dump the manure from trucks. The liquid portions are drained ' Soils and Fertilizers. 44 FEKTILITY AND FERTILIZER HINTS to these pits by pipes. It may not always be possible for a farm- er to build a covered cement pit but he can always afford to put a roof over the manure, for the cost of the shed will soon be returned in the increased value of the manure. The following table, the work of Biernatski, shows the com- position of uncovered and cov'fered manure. Water Per cent. Uncovered manure 83.78 Covered manure 76.54 Nitrogen Per cent. 0.47 0.67 Phosphoric acid Per cent 0.26 0.31 Potash Per cent. 0.43 0.76 Preservatives. — In the destruction of the nitrogen present in organic matter in manure, the aerobic bacteria produce ammonia and some of this gas unites with the carbon dioxide evolved and forms ammonium carbonate, a volatile compound. By adding moist gypsum (land plaster) to manure, the ammonium carbo- nate is converted into ammonium sulphate, a compound that does not pass away in the atmosphere. This latter compound is solu- ble in water and when manure is exposed to the leaching of rains, it is useless to employ gypsum. Gypsum is perfectly safe to use because it does not injure the feet of animals. Lime is objec- tionable because it liberates ammonia. Kainit, superphosphate and ground rock phosphate are sometimes used with good suc- cess, as they absorb nitrogen. These preservatives may be scat- tered at the rate of about one pound to an animal. They may also be economically used on covered manure heaps. HalP estimates that it will take about 100 pounds of gypsum per ton of manure to absorb the gases, as some of it is acted upon by the potassium carbonate in the urine. Physical Effects of Manure. — Manure has a greater value than is represented by its chemical composition. It improves the phy- sical condition of the soil by. 1. Producing a better moisture condition. 2. Producing a better texture. 3. Preventing mechanical losses by winds. 4. Benefiting grass land. ' Fertilizers and Manures. FARM MANURES 45 1. Manure Produces a Better Moisture Condition. — Manure when added to soils increases the water hokhng power of those soils because of its humus content. Humus absorbs water readily. A soil that has had manure added to it will resist drought better than one where there is little or no humus. During a heavy rainfall the soil with humus will absorb a great deal more water and give it up more gradually than one without humus."'' Manure helps to conserve the moisture supply of soil during dry seasons. 2. Manure Improves the Texture of the Soil. — Manure has a very beneficial effect on most soils in improving the texture. The addition of manure to sandy soils makes them more binding and increases their water holding capacity. Clay soils are made m.ore porous by the addition of manure. Some soils may pro- duce good crops during favorable seasons without much organic matter but when the season is bad it is almost impossible to get the soil in good mechanical condition for crops. Number of M.\ngoi:.d Plants Taking ioo as the Possible." Average of 7 years, 1901-7. Farm manure, minerals and nitrate of soda Minerals and nitrate of soda Minerals and rape cake 69 62 83 The plot receiving rape cake, which was applied at the rate of 2,000 pounds per year, shows the best results, but rape cake like manure supplies a great deal of humus. A better stand was produced with farm manure than with the artificial fertilizer. 3. Manure Prevents Mechanical Losses by Winds. — The losses occasioned by heavy winds on certain soils are sometimes more than one would expect. Dry light soils devoid of organic mat- ter are easily blown away by heavy winds. The addition of ma- nure to such soils tends to keep them moist and prevents such loss. 4. Manure Benefits Grass Land. — Manure benefits grass land not only by supplying plant food and increasing the moisture hold- ing capacity, but also in protecting this crop from the frosts 1 Hall, Fertilizers and Manures. 46 FERTILITY AND FERTILIZER HINTS of early spring, by the mulch produced. It is noticed that grass that has been manured in the fall has an earlier growth in the spring than such lands unmanured. Bacteriological Effects of Manure. — Manure when added to the soil aids the growth of bacteria that render plant food available. It also increases the number of these bacteria and supplies food for them, and fermentations are promoted that are very helpful in the production of crops. Time to Apply Manure. — In order to get all the value from farm manure it is better to apply it while fresh than when rotted. Manure in rotting loses some of its fertility. The Ohio Experi- ment Station have conducted experiments with fresh manure and exposed yard manure with the following crop returns for ten vears. Amount applied per acre tons. Yield per acre. Corn bushels. Wheat bushels. Hay pouncls. 8 8 16.03 22.24 8 21 9 73 6q8 1,280 The manure was applied to clover sod which was plowed under and followed by a three year rotation of corn, wheat and clover without the addition of any more manure. The yields favor the fresh manure with an increase of 6.21 bushels of corn, 1.52 bushels of wheat and 582 pounds of hay. Sometimes it is not practicable to apply manure while fresh as some crops, especially the quick growing market garden crops, require plant food that is available and so prefer rotted manure. It is common in this covmtry to apply fresh manure to grass land in the fall and turn it under in the spring. This practice is beneficial in that it supplies a great deal of organic matter for the succeeding crop. Corn is a crop that thrives on fresh manure and so it is well to apply manure in this condition to corn and follow this crop with one that prefers rotted manure. Amount of Manure to Apply. — The amount of manure to ap- ply depends upon the fertility and texture of the soil. Soils FARM MANURES 47 that already have considerable fertility sometimes require a light application of manure to improve their texture. Large applica- tions of manure on such soils would not be profitable. Most farmers use too much on iheir land at one time. Frequent light applications are more beneficial than large amounts applied at long intervals, as they keep the soil in an even state of fertility and losses by volatilization of nitrogen as gases and leaching of the soluble elements are less. Experiments show that small ap- plications give greater percentage increase than large applications although large applications give larger yields. Sometimes manure does not furnish sufificient plant food to satisfy the needs of the crop. An addition of some commercial fertilizer which supplies the necessary fertilizer constituents is beneficial in such cases to supplement the manure. How to Apply Manure. — It is best to spread the manure over the land as it is hauled. Some farmers dump the manure in little piles over the field and leave it in this condition for two or three months. When fermentations take place in these piles nitrogen passes ofl: in the air. This practice is objectionable because the soil under and around the piles gets most of the available plant food that is leached out, and the other soil does not receive its share. The result is that the succeeding crops grow uneven or in patches. There is no objection to dumping manure in small piles over the field if it is spread immediately. The hauling of manure to the field and hand spreading it is perhaps the common method used in this country. It is difficult to spread manure evenly in this way and after the manure is distributed, a brush drag should be used to scatter it more evenly. Manure spreaders distribute manure more evenly than any of the other methods in use. They are labor saving machines and although they usually carry less per unit of draft, they are considered a good invest- ment for those who have much manure to spread. A ton of manure spread uniformly gives better results than a larger amount applied unevenly. CHAPTER V. HIGH GRADE NITROGENOUS FERTILIZER MATERIALS. Nitrogen is the most important element to consider in the study of fertilizers. It is the most expensive and most fugitive of the essential elements. Nitrogen usually costs about three times as much as phosphoric acid or potash. To be in a form available as plant food it must be as nitrates which are readily soluble in water. The air is made up of nitrogen, carbon and oxygen and although plants utilize the carbon and oxygen most of them do not seem to be able to use the nitrogen. There is one class of plants, the legumes (peas, beans, peanuts, alfalfa, clover, etc.) of which we have spoken, that can utilize this elementary nitro- gen but most of our other plants do not possess this power. The organic matter, which is made up of animal and vegetable matter, serves as a source of nitrogen, but plants cannot use it in this form. It is understood then that there is plenty of un- usuable nitrogen in the air and in soils rich in organic matter, but it has no direct plant food value in these forms until it is prepared by electrical means, oxidized and acted upon by certain bacteria. Forms of Nitrogen. — Nitrogen exists in different forms in the many substances containing it. Not including the nitrogen in the air we may classify these forms into four groups, namely: 1. Organic nitrogen, which is found in vegetable and animal substances, generally as protein. 2. Ammonia nitrogen, which is found in ammonium sulphate. 3. Nitrate nitrogen, which is found in nitrate of soda (Chile saltpeter) and nitrate of potash. 4. Cyanamid nitrogen, which is taken from the air by electrical means and combined with calcium, carbon, etc. Of these four forms all are soluble in water except organic nitrogen. The organic form is included in many substances, both animal and vegetable, while the remaining forms are found principally in a few products. The Meaning of the Form of Nitrogen. — The fertilizer mater- ials furnishing nitrogen contain this element in different forms. HIGH GRADE NITROGENOUS FERTILIZER MATERIALS 49 We have said that the substances containing nitrate nitrogen, am- monia nitrogen and cyanamid nitrogen are sohible in water and the organic nitrogen is insohible in water. The nitrogen as ni- trates is always the same and of equal value no matter from what substance it is derived. The ammonia nitrogen is also of equal value and equal quantities of it are as good no matter wdiat material it comes from. The soluble nitrogen from ammonium sulphate, however, is not the same as the soluble nitrogen from nitrate of soda and the insoluble nitrogen of organic materials is not the same or of equal value. Therefore the source of soluble and insoluble nitrogen makes a difference in value of the forms of nitrogen. The solubility of nitrogenous substances in- tiuences the availability, or the rate with which the nitrogen in a suitable form is supplied so that the plant can assimilate it, to some extent. The organic form of nitrogen is so called because the nitrogen is combined with other elements as hydrogen, carbon and oxygen in organic matter. Organic nitrogen is different in the various substances. Some animal and vegetable materials are quite rich in nitrogen while others do not contain much and are perhaps not so valuable. Some organic substances may contain consid- erable amounts of nitrogen but in such a locked-up state that they are undesirable as plant food. When a substance gives up its nitrogen as nitrates readily we say that the nitrogen is in a form that is active ; it is quick acting, quickly available, readily assimilated, etc. When the nitrogen is locked-up we use the terms slow acting, slowly available, etc. There are many degrees of availability of the different forms of nitrogen and they range from the very quick acting of the soluble materials to the organic materials that may take two or three years or even longer before they give up their nitrogen for plants to use as food. There are many organic substances that contain nitrogen, but in such small amounts, or in such a locked- up condition that they cannot be used profitably in the manufac- ture of fertilizers. The principal sources of organic nitrogen will now be discussed. 50 FERTIUTY AND FERTILIZER HINTS The Vegetable Substances. Cotton-seed meal is one of the most important sources of vegetable nitrogen. It is usually a bright yellow product with a nutty odor when fresh.* For the year 1908, 929,287,467 pounds of cotton-seed meal were manufactured in the United States.^ Yields of Products from a Ton of Cotton-Seed.^ Pounds Linters 23 Hulls 943 Crude oil ( 37.6 gals. ) 282 Cake or meal 713 Waste 39 Total 2,000 Composition of Cotton-seed Meal. — The composition of cotton- seed meal varies a great deal. When it is not adulterated with hulls the variation in composition may be due to the season, the nature of the soil and the climate. Seed raised on high land is usually richer in nitrogen than seed raised on low land. The Texas meals seem to run high in nitrogen. In the past few years many of the manufacturers have been introducing ground cotton-seed hulls into their meal which of course lowers the value of this product. Cotton-seed meal is in great demand as feed for live-stock and the bright yellow meals are used for this pur- pose. The darker meals are not so valuable as feed and are usually sold for fertilizer. The dark color may be due to over- cooking, to fermentation, or to storing in a wet or damp place. If there is no loss. of nitrogen, the product is not injured for fertilizing purposes.* Value of Cotton-seed Meal. — Large quantities of this product are used in the South where it is especially suitable for the long growing crops as it supplies plant food during the whole season. An insect, called the boll weevil, is reducing the acreage and yield of this crop. If the entomologists do not find a way of ' 1908 Yearbook, U. S. Dept. of Agriculture. '^ Lamborn, Cotton-Seed Products. HIGH GRADE NITROGENOUS FERTILIZER MATERIALS 5 1 checking this pest the use of cotton-seed meal will be much less in the future. A physical examination will not always indicate its fertilizing value. Many of the meals have the hulls so finely ground that it is impossible to detect the extent of their presence with the naked Fig. s- — A field of cotton, the source of cotton-seed meal. eye. The color of a meal is not always an indication of its nitrogen content. Always purchase cotton-seed meal under a strict guarantee as this product is variable in composition and a physical examination of it does not show its fertilizing value. Linseed meal is another vegetable compound used for fertiliz- ing purposes. It is a by-product in the manufacture of oil from flaxseed. There are two classes of linseed meal, namely, the old and new process meal. The old process meal is obtained by press- ing out the oil from the cold or warmed crushed flaxseeds. In the new process the oil is extracted with naphtha and the naphtha driven ofif by steam. The old process and new process meal 5- FERTILITY AND FERTILIZER HINTS average about 5.3 per cent, nitrogen, 1.25 per cent, potash and 1.6 per cent, phosphoric acid. Linseed meal is not used ex- tensively as fertilizer because of the high price it commands as feed for live-stock. Castor pomace is the remaining product from the extraction of oil from the castor bean. It is poisonous to live-stock and therefore is used for fertilizer. It averages about 5.5 per cent, nitrogen, 1.8 per cent, phosphoric acid and i per cent, potash. As it decomposes rapidly in the soil it makes an excellent fer- tilizer.* The Chief Animal Substances. Dried blood is obtained from the large packing houses of the United States. There are tv^^o kinds on the market, namely, red and black blood. The red blood is obtained by drying blood very carefully with superheated steam and hot air. Should the blood be dried at too high a temperature it chars and turns black. If the blood is injured in any way it is sold as black blood. Red blood averages about 13.5 per cent, nitrogen with traces of phos- phoric acid while black blood is a more variable product but usually contains 12 per cent, nitrogen and i to 3 per cent, phos- phoric acid, depending upon the nature of the impurities. When bone is present the product contains sometimes as high as 4 per cent, phosphoric acid. Red blood is not used for fertilizer be- cause it commands too high a price for other purposes. Both red and black blood are ground and sold in a powdery condition. Black blood is a very valuable nitrogenous fertilizer which is in great demand and is very popular with the manufacturers of fertilizers in satisfying their formulas. It is one of the principal organic fertilizers used by manufacturers in the North. It is not used directly to any extent by farmers as the manufacturers purchase most of it. It is in a fine mechanical condition and is easy to mix with other materials. As plant food it gives ex- cellent results as it decays very rapidly thus furnishing nourish- ment during the early stages of the growing period. Sometimes salt and slaked lime are put in blood. It is very high in avail- ability being somewhat quicker than cotton-seed meal. HIGH GR.\DE NITROGENOUS FERTILIZER MATERIALS 53 Tankage is composed entirely of animal matter. It is the re- fuse from slaughter houses and consists of meat, bone, etc. (from which the fat has been extracted) and more or less dried blood. Animals condemned as unsuitable for food are made into tankage. The phosphoric acid in tankage is slowly available as it is sup- plied principally by ground bone. The nitrogen is derived prin- cipally from meat and blood. When the percentage of bone is large, the phosphoric acid is high, and the nitrogen content is low. and when there is a.i excess of blood and meat, the ni- trogen is high and the phosphoric acid low. Grades of Tankage. — There are several grades of tankage found on our markets. The most popular nitrogenous grades are those containing 8, 9, and 10 per cent, ammonia which are equivalent to 6.58, 7.41. and 8.23 per cent, nitrogen, and 6.56, 7.64, 10, and 12 per cent, bone phosphate of lime, which are equivalent to 3> 3-5> 4-58< and 5.5 per cent, phosphoric acid. There are many other grades of tankage sold that carry more phosphoric acid and less nitrogen, but these are classed as bone tankages and will be later described under phosphates. Concentrated tankage is still another grade and the richest of all since it contains more nitrogen and is a more uniform product. It is made by evaporating, wastes that contain animal matter in solution, or in other words the tank water. It us- ually contains 10 to 12 per cent, nitrogen and small amounts of phosphoric acid. Variation in Tankage. — Because of the great variation in the chemical composition of tankage (no two shipments hardly ever run alike, for the manufacturers cannot seem to control the com- position of their output on account of the variation in the by- products), great care must be exercised in purchasing. The prod- uct should be bought on its chemical composition and not nec- essarily on its guarantee, for it may or may not reach its stated composition. Hoof meal and hair are sometimes present in shipments of tankage. For sugar-cane, cotton-seed meal has been found to be more valuable than tankage of the same ni- trogen content. Nevertheless, tankage is a valuable fertilizer 54 FliRTlI.ITY AND FfiRTlLIZKR HINTS and its value depends a great deal on its nitrogen content. It is suitable for crops having a long growing season. About 1,000,000 tons of tankage and dried blood are produced annually. Azotin, meat meal, flesh meal, dried meat, animal matter and ammonite are practically the same product, but are by-products from different manufacturing establishments. IVIost of this prod- uct comes from the slaughtering houses and beef extract factor- ies. It is a rich organic fertilizer containing about 13 per cent, nitrogen, but it may run higher or lower than this depending upon its purity. This product is made up generally of the flesh refuse of dead animals from which the fat has been extracted and the remains dried and ground. It is different ivoni tankage because it does not contain bones. Steamed horn and hoof meal averages about 12 to 15 per cent, nitrogen and is principally marketed by the large packing houses. The choice horns and hoofs are sold for the manufacture of Inittons, combs, and novelties, and the imperfect and oft'-col- ored horns antl hoofs are treated with steam, under high pres- sure, which renders the nitrogen more available and permits of the product being ground to a fine powder. Horn and hoof meal was not formerly thought much of, but since it has been subjected to superheated steam the product has been much sought after b}' the manufacturers of fertilizers. It is produced only in limited quantities and is not as valuable as dried blood, but has a fairly high degree of availability, according to recent investigations.* Dry Ground Fish. — This is also called fish scrap and fish guano and has a yellow color. It is obtained principally from canning factories where the refuse as bones, skin, heads, fins, tails, in- testines, etc., of edible fish are saved, dried and ground. Estab- lishments expressing oil and manufacturing glue from inedible fish as Menhaden, furnish a considerable supply. The average annual catch of Menhaden is about 600,000,000 fish, which pro- duce 70,000 tons of fish scrap and 35,000 barrels of oil. Thirty factories with 70 steamers are engaged in this industry and the HIGH GRADE NITROGENOUS FERTILIZER MATERIALS 55 largest catch was in 1903 when 1,000,000,000 fish were caught.' The whale bone interests, after the bones are removed and the oil extracted from whales, utilize the remainder in the prepara- tion of dry ground fisR. Dried ground fish is variable in composition depending upon the nature of the materials of which it is made. The greater the percentage of bone, the higher is the phosphoric acid content and the lower the nitrogen, and the less bone, the higher the nitrogen and the lower the phosphoric acid. The amount of oil left also influences the composition. It usually ranges from 7.5 to 10.5 per cent, nitrogen, 5.7 to 16 per cent, phosphoric acid, with an average of 8.5 per cent, nitrogen and 9 per cent, phosphoric acid. It is a popular and valuable fertilizer and large quantities are used in the North. Most sections of the South are too far away from where it is manufactured to prevent using it at its market value. Dry ground fish is readily decomposed in the soil and is therefore quick acting. It is not considered as valuable as dried blood. King crab is obtained on the Atlantic coast and is dried and ground, in which state it is utilized by fertilizer manufacturers. It contains about 10 per cent, nitrogen and is similar to dried ground fish in fertilizer properties. Guano, or natural guano, is another important source of ni- trogen. It was used as early as the 12th century in Peru. On the west coast of South America there are thousands of sea fowl. These birds have roosting and breeding places along the unin- habited portions of the coast and many of them make their home on the smaller islands ofif the coast of Peru and also on the main- land, because of the abundant supply of fish in that region. The excrement voided by these birds is rich in nitrogen and phosphoric acid because their food, which is fish, is rich in these constit- uents. During breeding seasons they literally cover these is- lands and the young birds after they are hatched are fed on fish until they are able to fly. The excreta from the old and the young birds, feathers, and the remains of the young birds that die, all go to make up guano. As this region is practically ' American Fertilizer. 56 FERTILITY AND FERTILIZER HINTS rainless and has a dry hot temperature, these remains dry out rapidly and are preserved without much loss of phosphoric acid or nitrogen. There is some loss of nitrogen in these Pe- ruvian guanos due to the formation of ammonium carbonate, a volatile form, and to leaching by occasional rains. However, these deposits have been the best nitrogenous guanos in the world. There are deposits in other parts of South America, West Indies, Africa, Australia, Asia, and the islands of the Pacific, but the Peruvian deposits are the most notable. There is a wide dififer- ence in the composition of guanos. In Peru, guano from the same island shows variation in chemical composition, while guano from different islands shows even a greater variation. The old- est deposits usually contain less nitrogen and more phosphoric acid than the more recent. In a wet, damp climate, fermenta- tion, aided by the presence of moisture, destroys all or most of the organic matter driving off the nitrogen as ammonium carbo- nate. Soluble phosphoric acid is also lost in such regions. Therefore it is easy to understand the wide differences in the composition of these deposits. Guanos range from rich nitrogenous deposits to phosphatic de- posits which only contain traces of nitrogen and considerable amounts of phosphate of lime. There are therefore two classes of guanos, namely, nitrogenous and phosphatic. The phosphatic guanos will be discussed under phosphates. Formerly guano was used more extensively in the United States but most of the nitrogenous deposits have been exhausted so that the importations are rather decreasing from year to year. There were 16,155 tons imported from Peru in 1905 and 5,500 tons in 1909.^ The nitrogen in guanos is present in different forms. Some of it is as nitrates, some as ammonia and some as organic nitro- gen. The presence of these various forms makes the nitrogen- ous guanos valuable because they supply plant food during the whole growing season.* In Mexico there are deposits of bat guano, many of which are good nitrogenous fertilizers, but they are not being worked be- ' 1910 American Fertilizer Handbook. HIGH GRADE NITROGKNOUS FERTILIZER MATERIALS 57 cause of poor transportation facilities. There are also deposits of bat guano in Texas. The bat guanos are not as a rule as valuable as the high grade nitrogenous Peruvian guanos.* Ammonium sulphate is unlike the organic compounds as it is not a natural product but a manufacturing by-product. When pure it is a white crystalline salt but sometimes foreign substances become mixed with it, in the course of manufacture, which causes it to be grey, yellow, or blue. It is soluble in water and vola- tile, that is, it will pass ofT as gas when strongly heated over a flame. It is derived from the distillation of coal in the manu- facture of gas ; from the distillation of bones in the manufacture of bone-black; and from the manufacture of coke from coal. Coal was formed from vegetable matter and most coals average about 1.8 per cent, nitrogen. When coal is heated, as in the manufacture of gas or coke, about Vs of the nitrogen as am- monia is driven ofT and this ammonia may be saved by washing it in water in special apparatus. The solution thus formed is then distilled into sulphuric acid, concentrated and the crystals of sulphate of ammonia separate out on standing. Bones contain about 3 to 4.5 per cent, nitrogen and the nitrogen as ammonia is recovered in a similar way as in distilling coal or coke, when they are subjected to dry distillation by heat, as may be practiced in the manufacture of bone-black.* Composition and Availability. — Sulphate of ammonia when pure contains 21.2 per cent, nitrogen but the commercial article usually runs about 20 per cent. It is in a form very suitable for distri- bution in the soil and is readily converted into available plant food. It is more available than the organic forms. It is a quick acting fertilizer and suitable therefore for quick returns in crop production, an especial advantage for truckers and market gard- eners. It is sometimes substituted for nitrate of soda. As it is readily soluble in water it should be used sparingly, and frequent small applications are more effective than large amounts applied at long intervals. A continued use of it may cause the soil to become acid because of the sulphates left in the soil after the nitrogen is given up.* 58 FERTILITY AND FERTILIZER HINTS Nitrate of Soda. — This is a white or yellow or pink crystalline salt. The nitrogen in nitrate of soda is in a form that can be used by plants without undergoing any change. Nitrate of soda is the highest in point of availability of any of the nitrogenous fertilizer materials. It induces roots to grow deep. The ni- trate diffuses into the subsoil and the plants send down their roots for it. This is indeed of great benefit because it enables the plant to better stand dry spells and it increases the area of plant food supply. It is found in extensive deposits on the west coast of Chile and is often called Chile saltpeter. The entire deposits are found in layers sometimes 6 feet thick, about 2 to 10 feet below the surface, and are blasted out and treated to rid the product of impurities.* Composition and Properties. — Nitrate of soda contains 15 to 16 per cent, nitrogen and the average product .found on the American market contains 15.3 per cent, nitrogen. It is very soluble in water and therefore it should be supplied in small quantities frequently to prevent losing it by leaching. It should be kept in dry storage as it absorbs water and is liable to liquefy It is hard to distribute evenly on the soil unless it is mixed with earth or some other material. On account of its caustic action it should be applied around the plants and not on them as it spots green vegetation. It should be kept away from live-stock as it is poisonous. Acid phosphates when damp should not be mixed with nitrate of soda as nitrogen is lost. The acid attacks the nitrate of soda liberating the nitrogen.* The utilization of nitrogen from the air by artificially uniting and fixing it with other elements to form compounds that could compete with the other nitrogenous fertilizer materials has at- tracted the attention of chemists and investigators for many years. It seems that at last the problem has been solved and it is now only a matter of a short time when the present modes of manu- facturing artificial nitrogen compounds will be so perfected that we will not be forced to worry about the future supply of this important element. There are two of these artificial nitrogenous HIGH GRADE NITROGENOUS FERTILIZER MATERIALS 59 compounds being sold to-day, namely, calcium nitrate and calcium cyanamid. Calcium nitrate sometimes called lime nitrogen is manufactured, with cheap water-power, in Notodden, Norway. It contains about 13 per cent, of nitrogen and can be sold at a profit for $40 per ton, which is equivalent to nitrate of soda at about $50 per ton. Recent experiments sh.ow it to be as valuable as nitrate of soda in crop producing power.* Calcium cyanamid is a grey black crystalline powder. It is made from limestone, coke and nitrogen gas with the aid of the electric furnace. When calcium cyanamid was first placed upon the market it contained small quantities of substances in- jurious to young plants, and the manufacturers now claim to put out a product in which these poisonous materials are absent. It carries 17 to 20 per cent, of nitrogen.* Properties. — About 80 per cent, of the nitrogen in the improved cyanamid is as cyanamid and the remaining 20 per cent, as ni- trate. Calcium cyanamid contains about 20 per cent, of free lime which absorbs water and carbonic acid gas from the air, causing the lime to slake and the product to decompose so that ammonia is formed. This ammonia is not lost to any great extent when the product is kept in bags, but if it is exposed in a loose pile the loss may be appreciable. Calcium cyanamid is soluble in water and when steam is introduced into it ammonia is driven ofif. In the soil the ammonia is given ofif by tiie action of water arid soil micro-organisms. The action with water is : CaCN, -f 3H0O = CaC03 + 2NH3. Fertilizing Value. — Experiments show that this product has about the same fertilizing value as ammonium sulphate on most soils. It is therefore highly available. It would no doubt show to good advantage on soils deficient in lime. Care should be exercised in its application. When the product contains injurious substances it is liable to injure seedlings and it is safe practice to apply it sometime before the seed is planted. It is thought to be injurious when used as a top dressing but this point has not been thoroughly proved. Should the '"Improved Cyanamid" be free from injurious substances it will prove a much more de- sirable fertilizer.* CHAPTER VI. LOW GRADE NITROGENOUS MATERIALS AND FUNCTIONS OF NITROGEN. The nitrogenous substances discussed in the previous chapter are all considered high class and valuable standard materials. Some of them as the mineral compounds are immediately or al- most immediately available, while the organic materials, both animal and vegetable, vary in their degree of availability, but stay with the crop during the whole or the greater part of the season. The high prices of these desirable and valuable nitrogenous materials have caused some of the manufacturers of commercial fertilizers to seek and use cheaper sources of nitrogen. Many of these cheaper materials, to be sure, are rich in nitrogen but really of little value as the nitrogen is present in such forms as to be inert or else too slow acting to stimulate plant growth. Many of these low grade nitrogenous waste products are im- ported from foreign countries yet we produce our share of them in this country. They are made up of wastes from the manu- facture of silk, wool, feathers, combs, hair, skins, sugar and some few are derived from vegetable sources. The materials most commonly used will be discussed. Raw Leather Meal. — This product contains about 8 per cent, nitrogen which is in a form that is very slowly utilized by plants ; it may remain in the soil for two or three years before decaying. It takes such a long time for it to decompose that it has not much value for fertilizing purposes. One of the objects in the treat- ment of leather is to prevent its decay and for this reason raw leather may remain in the soil for a very long time before under- going any change. This material is sold varying in the degree of fineness from a dust to coarse particles. If it is ever used it- should be powdered. At best it is a tough material. Dissolved leather, sometimes called treated leather or extracted leather, is made in Belgium. The raw leather is roasted and very finely ground and treated with superheated steam which removes LOW GRADE NITROGENOUS MATERIALS, ETC. 6l most of the tannic acid. It is then acidulated with sulphuric acid to fix the nitrogen and render it more available. This material is being used by the manufacturers in the United States to quite a considerable extent because it is cheaper than the more desirable nitrogenous materials per unit of nitrogen. This product con- tains about 8 per cent, nitrogen and is more valuable than raw leather. Feather waste and various skin wastes are also saved for fer- tilizing purposes. Hair and fur waste is rich in nitrogen. It is unsuitable as fertilizer because it is so slowly decayed. When properly treated with sulphuric acid and rendered assimilative for plants it is more valuable. Hair to a limited extent is often found in tankage. Mora meal is a vegetable product, brown in color, which is im- ported from Europe. The mora seed, which are grown in India and probably other tropical countries, are sent to Europe where they are subjected to pressure and the oil extracted. The re- maining pomace is ground and sold as mora meal. This product has been used for the past nine years in the United States and the consumption has increased every year. It carries about 2.5 per cent, of nitrogen which is of low avail- ability. It is not sold with any guarantee of nitrogen, phosphoric acid and potash, but on a flat basis. It is used by manufacturers of commercial fertilizers principally as a dryer and filler. It is good for both of these purposes because it is an excellent ab- sorbent and bulky. Beet Refuse. — This compound is a grey black powdery sub- stance. It contains from 5 to 7 per cent, nitrogen and about 0.5 to I per cent, potash. One manufacturer used this compound in some of his mixtures because he believed it would kill in- sects in the soil. He believed this because of the presence of sulpho-cyanic acid in this compound. Scutch. — This is a by-product or waste product in the manu- facture of glue and the dressing of skins. It is manufactured in England and contains about 7 per cent nitrogen. Horn and hoof meal, horn shavings, etc., are products obtained from slaughtering houses or by-products in the manufacture of 62 FERTILITY AND FERTILIZER HINTS combs and similar articles. In the raw state they are extremely hard to grind and are not valuable in this form because they decay too slowly to supply plant food with any degree of rapidity. Fig. 6. — A stock yards scene where tankage, blood, horn and hoof meal and similar fertilizer products are saved. When steamed and pulverized they become high grade products as mentioned in the previous chapter. Wool waste, shoddies, etc., taken collectively is the term ap- plied to any waste from silk or wool manufacturing which is no longer profitable for making cloth. It is slow to decay and is rather undesirable as fertilizer. It is often coarse and bulky and hard to mix in a manufactured fertilizer or to distribute evenly when applied to the soil* It is sometimes treated with superheated steam, the liquid evaporated to dryness and the product ground, or else it may be acidulated with sulphuric acid for a long time (2 months) to LOW GRADE NITROGKNOUS MATERIALS, ETC. 63 render the nitrogen available. When treated by either of the above methods, it is known as dissolved wool, shoddy, etc., and is of course more valuable than the raw products from which it is made. Garbage Tankage. — Many of the large cities have plants where the garbage is accumulated. It is dried, or charred, or steamed, or extracted and the treated product is sold as garbage tankage. This material contains about 2 per cent, of nitrogen which is in a form that is slowly assimilated by plants. It is not a valuable fertilizer.* Dried peat, sometimes called dried muck, is used principally by the manufacturers because of its excellent drying properties. The use of it enables the manufacturer to put out a fertilizer in a fine mechanical condition which may be distributed evenly on the soil. This material varies in composition, depending on the amount of vegetable and mineral matter present, but may be considered as averaging 1.5 to 2 per cent, of nitrogen. Availability of Nitrogenous Fertilizer Materials. — The only cor- rect way to determine the value of any nitrogenous substance is by running experiments with growing plants. The high grade products as nitrate of soda, sulphate of ammonia, dried blood, cotton-seed meal, linseed meal, castor pomace, dry ground fish, tankage, ground bone, steamed horn and hoof meal, etc., have been tested by field experiments to determine their crop produc- ing power. Laboratory methods have been introduced to corre- spond as near as possible with the field results. The availability of nitrate of soda is always taken as 100 and the availability of the other materials is based on the results secured when compared to nitrate of soda. Should nitrate of soda give an increased yield of 500 pounds per acre for a crop, the yield of a nitrogenous fertilizer of 75 per cent, availability would give an increase of 375 pounds, etc. Not Always Possible to Run Field Experiments. — To conduct field experiments is often impossible, because of the great expense, the long time required, the difference in soils, the variation in seasons, the ability of the various crops for securing plant food, the association with other fertilizing materials containing phos- 64 FERTILITY AND FERTILITY HINTS phoric acid, potash, lime, etc., so that much of our information on the low grade products has been worked out in the laboratory by chemical methods. These methods are not entirely satisfac- tory but indicate to a great extent the relative values of nitrog- enous fertilizers, as to whether they are high grade, medium grade or low grade. * Value of Low Grade Materials. — Raw leather, wool waste, shoddy, hair, etc., may be rendered fairly available as plant food by special treatment, but such treatment usually is expensive and the market value does not always permit it. The standard high grade materials are always to be preferred and these low grade wastes cannot be sold unless they are much cheaper. Hence these low grade substances are usually only partially treated or not at all, so that they have very little value as fertilizer and the use of them is liable to cause disappointment and poor yields. They are not always sold alone but are sometimes mixed together. The writer has examined a product imported from Belgium and sold as Foreign Imported Tankage which was made up of shoddy, wool waste, hair, and leather and was only partially treated. Most of the material was in the raw state and in poor mechanical condition ; chemical methods showed it to be poor plant food. This material contained about 7 per cent, nitrogen with traces of phosphoric acid. Should any of these low grade substances be used, the purchaser should demand that they be powdered, or ground very fine, in order to give the soil organisms a better chance to decompose them. The purchaser should not expect to get quick results with many of these wastes as some of them, particularly the raw leather, may remain in the ground for two or three years without any apparent change. The Use of Low Grade Materials is Increasing. — The use of these low grade materials seems to be increasing and many manufac- turers are using them in their low grade cheap fertilizers which carry low percentages of nitrogen, to a greater or less extent. The writer believes that some of these materials have no doubt been misrepresented to the manufacturers or else they would not use them. In order to insure future business they endeavor to put out fertilizers that will give good crop returns, and by satisfy- LOW GRADE NITROGENOUS MATERIALS, ETC. 65 ing their formulas with much of this class of material the poor crop returns will surely hurt them in repeating orders. Some of these materials are said to be used as dryers by the manufacturers (peat and mora meal for example) but analyses of fertilizers containing them often show that the manufacturers counted the nitrogen content in making the fertilizers. Peat to be sure is a valuable filler for fertilizers as in addition to its drying qualities it contains about 30 per cent, of humus, but its nitrogen is not readily available and fertilizers containing it should have their guarantees satisfied by the use of more available substances. The Nitrogenous Materials to Use. — We have learned that most plants assimilate nitrogen from the soil as nitrate and occasion- ally as ammonia. We also know that certain organisms in the soil convert the nitrogen from organic sources into ammonia and from ammonia into nitrates. Therefore it is reasonable to suppose that substances containing nitrogen as nitrates are to be preferred for immediate results in plant growth. As ammonia is converted to nitrates in the soil, materials containing nitrogen as ammonia, as ammonium sulphate for example, are less active than nitrate of soda. Again, nitrogen from organic sources is less active than from substances containing nitrogen as nitrates or ammonia, as organic nitrogen must be changed to ammonia and nitrates before being usable, and we would use materials furnishing this form of nitrogen for slower and more lasting results. We have seen that the nitrogen from organic products varies a great deal in the power of giving up or holding nitrogen. Dried blood and cotton-seed meal, for example, give up nitrogen quicker than tankage and dry ground fish, and these latter sub- stances do not hold nitrogen as long as leather preparations and wool waste. Therefore in selecting the proper nitrogenous ma- terial or materials to use we must consider the condition of the soil, climate, locality, kind of crop, etc. For Immediate Results. — Should immediate results be desired, applications of nitrate of soda, sulphate of ammonia, lime nitrate, or calcium cyanamid should serve the purpose. The locality may prevent the use of organic substances as a certain amount of heat (37° F.) is required for the soil organisms to convert organic 66 FERTILITY AND FERTILIZER HINTS nitrogen into nitrates. A wet season checks nitrification and hence nitrate of soda and sulphate of ammonia should give better results than the organic materials. For Soils Well Supplied and Long Growing Crops. — Should the soil have a sufficient natural supply of organic nitrogen as from some leguminous crop plowed under, etc., perhaps no organic nitrogenous material should be applied and a small application of some one of the mineral salts may suffice to give the crop a start. If the crop is a long growing one, an organic product may prove best, as it gives up its nitrogen in smaller amounts and more slowly than the chemicals and will thus stay with the crop the whole season. Mixtures of minerals and organic materials may sometimes be best so as to enable the plant to get a quick start by supplying immediate food and when this supply is ex- hausted, to furnish nourishment from the organic sources for the remainder of the season. The fertilizer manufacturers often use two or three different nitrogenous substances of different forms, as nitrate of soda, sulphate of ammonia and cotton-seed meal, in their fertilizers to allow the plant a continual supply of available nitrogen. Mixtures of organic materials of different availabilities may make excellent combinations for certain crops. For Large Crops and Building up the Soil. — Should a large crop be desired the chemicals and the active organic substances would perhaps be preferable, but should the building up of the soil for some future crop be wished, the less active organic materials would prove more valuable than nitrate of soda, ammonium sul- phate, lime nitrate, calcium cyanamid, dried blood, cotton-seed meal, etc., as these materials are all changed to the nitrate form, except nitrate of soda which is already in this form, either im- mediately or during the season and would in all probability be lost because nitrates do not become fixed in the soil and are readi- ly washed away by heavy rains. The nitrogen in organic ma- terials is not soluble in water to any great extent as is the case with nitrate of soda, sulphate of ammonia, lime nitrate and cal- cium cyanamid so that the losses by leaching of the former sub- stances are not considerable as compared to those of the latter. It is evident then that the farmer should select those sub- LOW GRADE NITROGENOUS MATERIALS, p:TC. 67 stances that will give the best results for his conditions and not purchase nitrogenous fertilizer that some neighbor recommends - -^tti^ ^^S'l'^-.i'i. P"ig. 7.— A good crop of hay, the result of judicious soil management. who secured good crops with an entirely different crop and soil, etc.* Functions of Nitrogen. — Nitrogen increases growth and defers maturity. In a certain parish in Louisiana where the people were ignorant along fertilizing lines, cotton-seed meal was the only fertilizer known to them. So year after year they applied this fertilizer to their cotton. For the last three years that they practiced this, they produced excellent large cotton plants but the crop did not mature well or produce scarcely any cotton. The people could not understand it. They did not know that cotton-seed meal was a nitrogenous fertilizer nor did they know- that nitrogen produced growth. The Experiment Station was called upon to investigate the trouble and as the soil was natur- ally rich in potash, applications of acid phosphate corrected the condition. The above example shows the results of an excess of nitrogen in producing growth and deferring maturity. 68 FERTILITY AND FERTILIZER HINTS When excessive nitrogen is applied to potatoes it produces a vigorous growth of vines but very few tubers are formed. Should an excess of nitrogen be supplied the small grain crops it would cause them to lodge and produce grain of inferior quality and the excess of the weight of the crop to the weight of the grain would be high. Excessive nitrogen retards the formation of fruit. It produces growth of wood and leaves when the fruit should be forming. When nitrogen is lacking in the soil the plants do not grow so high as when the supply is sufficient. With crops grown on such soils the proportion of grain or seed to the weight of the crop is high. No matter how much phosphoric acid and potash there may be in the soil the crops can only use quantities in proportion to the growth of the plants, and the growth of plants will be in proportion to the nitrogen supply. Generally speaking an application of a nitrogenous fertilizer will produce increased yields without the application of potash and with an occasional supply of phosphoric acid. The nitrogen produces a better leaf development, a better growth, the color of crops become a darker green, and the crop matures later. Often the supplying of nitrogen alone will increase yields to such an extent that farmers may overate the value of this constituent. On soils that are deficient in organic matter, that have been continually cropped, the need of nitrogen is generally greater than phosphoric acid and potash.* Market gardeners often take advantage of the power of ni- trogen in the growing of lettuce and similar vegetables. Vege- tables grown on soils more than amply supplied with nitrogen pro- duce more delicate and tender vegetables, especially lettuce and cabbage, but they do not stand shipping so well ; although better for immediate consumption than vegetables grown on average soils they wilt and spoil quickly and are not popular with the commission houses. The cell walls and tissues are not so strong with crops grown on excessive nitrogen as when not. Excessive Nitrogen Invites Diseases. — Crops grown on soils that have excessive nitrogen are more susceptible to plant diseases than on average soils. This may be noticed to a limited extent LOV\' GRADE NITROGENOUS MATERIALS, ETC. 6<; with oats and wheat. When the season is especially favorable to the production of nitrates in the soil during the growing period or when oats and wheat are grown on rich nitrogenous soils rust is more prevalent than usual. Plant diseases due to excessive nitrogen are perhaps more noticeable with crops grown under glass than outside. Most of the soils that are used in hothouses are very rich in nitrogen and the high temperatures kept renders nitrification very rapid. The color of the leaves of hothouse crops becomes a darker green when excessive nitrogen is present ; the leaves become tender and thin and seem to be easily attacked by certain fungi unless extra precautions are taken. Cucum- bers are especially susceptible to disease in the presence of ex- cessive nitrogen. CHAPTER VII. PHOSPHATES. Phosphates are those materials that contain phosphoric acid. The phosphates occur as phosphate of lime, iron and alumina, in which compounds the phosphoric acid is united with lime, iron and alumina respectively. Since the phosphoric acid in fer- tilizers is derived mainly from phosphate of lime we will limit our treatment of the subject to the important materials compos- ing this group. The phosphates of lime occur as organic, organic and mineral, and mineral compounds. Bones. — The chief source of phosphoric acid from the organic phosphates of lime are bones. The composition of bones is variable. The bones from old mature animals are richer in phos- phate of lime than bones from young animals. Different bones from the same animal also show a variable composition, as the harder more compact bones are richer in phosphate of lime than the softer, porous ones. Raw Bone-Meal. — This is the finely ground product derived from raw bones and it contains all the constituents of them. It carries considerable organic matter much of which is in the form of fats, which makes it hard to grind and to handle on the market. The presence of organic matter makes it objectionable. The fatty matter, which slowly decomposes, tends to make this fertilizer very slowly available for plant food and so it is called a slow acting fertilizer. Raw bone-meal usually contains about 19 to 25 per cent, of phosphoric acid and 2 to 4 per cent, of nitrogen, with an average of 22 per cent, of phosphoric acid and 3.5 per cent, of nitrogen.* The phosphates are sold to the trade on the basis of tri- calcium phosphate present. To convert tricalcium phosphate to phosphoric acid, multiply by the factor 0.4576 and to get the equivalent of tricalcium phosphate from a given percentage of phosphoric acid multiply, by 2.185. Steamed Bone-Meal. — Most of the bone sold for fertilizing PHOSPHATES 71 purposes has been boiled or steanietl in the rendering' factories to extract the fats and nitrogenous compounds which are used in making soap, glue, and gelatine. The bones are then ground or pulverized and sold as steamed bone-meal, bone-meal and bone- dust. This product is variable in composition, ranging from 17.5 to 29 per cent, of phosphoric acid and 1.5 to 4.5 per cent, of nitrogen. Good clean bone-meal should contain at least 2.5 per cent, of nitrogen and 25 per cent, of phosphoric acid. The treatment of the raw bones afifects the final composition of the product (steamed bone-meal) ; the boiling or steaming reduces the nitrogen content and increases the phosphoric acid. Steamed bone-meal is a more quickly available fertilizer than raw bone-meal and is therefore better for most crops. There is a great difference in the steamed bone-meals put upon the market not only in the composition but in the hardness of the product. Steamed bone-meal from some factories is more porous and softer than from others. Some factories put out a product that crumbles easily while others sell meal that is ex- tremely hard.* Degree of Fineness. — The bones when sold for fertilizing pur- poses are ground tine and are known as fine ground bone, bone- meal, bone-dust and bone-flour. The mechanical condition of fineness does not affect the composition but increases the avail- ability of the product for plant food. 1 fence the finer the bones are ground the more valuable they are as quicker acting fertilizers. These products are generally valued according to their degree of fineness and chemical comjiosition. It must be remembered that all bone-meals give up their plant food slowly and are not de- sirable for immediate results in the production of crops.* Bone-Black. — In the manufacture of bone-black, the choicest bones are selected, cleaned and dried. They are then put in air- tight vessels, heated and distilled until all the organic or volatile matter has passed off'. The product is then ground to a coarse consistency and sold to the sugar refineries for clarifying or de- colorizing syrups in the manufacture of white table sugar. After it has served its usefulness in the sugar refineries it is sold for 6 72 FERTILITY AND FERTILIZER HINTS fertilizer. It contains usually about 30 per cent, of phosphoric acid in the form of phosphate of lime. It is a slow acting fertilizer and is not used extensively in this condition.* Bone-Ash. — When bones are burned the remaining product is called bone-ash. It is not manufactured a great deal in this country because of the greater value of bone-black. It is an ex- cellent fertilizer and the only shipments received to-day come from South America where the bones are burned to save freight. In burning bones the nitrogen is driven off, so tliat bone-ash is valuable only for the phosphoric acid it contains. It varies in phosphoric acid content from 30 to 39 per cent. It is used in some countries in the manufacture of fertilizers.* Bone Tankage, — This product is composed entirely of animal matter. It is the refuse from slaughter houses and rendering factories and consists of meat, bone, etc. (from which the fat has been extracted), and sometimes a little dried blood. There are many grades of tankage put upon tlie market. Those tankages coming under the head of bone tankage contain considerable bone and small amounts of meat and sometimes dried blood. The amount of phosphoric acid in tankage varies with the bone con- tent. The more bone present the higher is the percentage of phosphoric acid. The bone tankages range from 11/2 per cent, to 20 per cent, of phosphoric acid. Those tankages falling be- low iiy2 per cent, of phosphoric acid are discussed under the chapter on nitrogenous fertilizer materials. The phosphoric acid in bone tankages has about the same value as in steamed bone, since both of these products are steamed or boiled to extract the fats, etc. The bone tankages are very popular among farmers in certain sections of this country. Dry Ground Fish. — This is also an organic source of phosphoric acid from phosphate of lime. The phosphoric acid content de- pends upon the amount of bones present. This product was de- scribed with the fertilizer materials containing nitrogen. Suffice it to say that dry ground fish carries from 6 to 16 per cent, of phosphoric acid. PHOSPHATES 73 Average Composition of Organic Phosphates of Lime. Raw bone-meal .... Steamed bone-meal Bone-black Bone-ash Bone tankage Dry ground fish . . . . Phosphoric acid Per cent. Nitrogen Per cent. 22 25 30 36 1 1.5-20 9 3-5 2.5 4-6 8.5 The phosphoric acid present in raw bone-meal, steamed bone- meal, bone tankage, bone-black, bone-ash and dry ground fish is insoluble in water and slowly available as plant food. Mineral Phosphates. — These occur in natural beds in different parts of the world. According to Van Horn in the American Fertilizer, the known phosphate deposits of the United States are distributed principally among four localities : ( i ) along the west coast of Florida, running back 20 to 25 miles inland; (2) along the coast of South Carolina, extending 6 to 20 miles in- land; (3) in central Tennessee; and (4) in an area comprising southeastern Idaho, southwestern Wyoming, and northeastern Utah. In addition to these areas, some deposits occur in north- central Arkansas, along the Georgia-Florida State line, and in North Carolina, Alabama, Mississippi, and Nevada, but these are mainly of low grade and not utilized at the present time. The three important deposits first mentioned have been worked from ten to thirty years ; the fourth is a new field which has as yet had but a small output." The most important deposits in this country are in Florida, South Carolina, and Tennessee and the production in the United States amounts to over two million long tons (2,240 pounds) a year while that of the remaining countries approxi- mates one million tons. South Carolina phosphates were first put upon the market in 1868. There are two kinds of phosphates found in South Caro- lina, namely, the land and river phosphates. The land phosphate IS mined from the land and is known as land rock, while the river phosphate is obtained by dredging rivers and is called river 74 FERTILITY AND FERTILIZER HINTS rock. These phosphates occur in the form of nodules varying in weight from a fraction of an ounce to more than a ton. Whether the rocks are mined or dredged, they are washed free from the clay and other adhering matter and dried, when they are ready for shipment. When phosphate rock is ground or pulverized it is known as floats and is used in this form in the middle western states quite extensively. The land rock is light fawn colored; the river rock is black; both are very hard. The South Carolina land rock averages about 50 per cent, tricalcium phosphate, which is equivalent to about 23 per cent, of phosphoric acid, and the river rock runs about 50 to 60 per cent, tricalcium phosphate, which is equivalent to 23 to 27.5 per cent, of phosphoric acid. Including the year 1908, South Carolina's total production of phosphates was 12,138,454 long tons of rock, of which about one-third was shipped to Europe. The discovery of the Florida phosphates decreased the exportation of those from South Caro- lina, to about 30,000 tons annually, because the Florida phosphates that are exported contain more phosphoric acid and less im- purities.* Florida phosphates occur as soft phosphate, pebble phosphate and boulder or hard rock phosphates. The soft phosphate resembles a whitish clay and generally contains 50 to 60 per cent, of tricalcium phosphate, which is equivalent to 23 to 27.5 per cent, of phosphoric acid. The hard rock ranges from 60 to 75 per cent, of tricalcium phosphate, which is equivalent to 27.5 to 34.3 per cent, of phosphoric acid, although many samples show even a higher content of phosphoric acid. Most all of the high grade phosphates of Florida are exported to Europe where they find a ready market. Florida has put out 14,087,833 tons of phos- phate rock from 1888 to igo8.* Tennessee Phosphates. — These are perhaps the most extensive deposits in the United States that are being worked. Their com- mercial importance was made known in 1893. The Tennessee phosphates are known as brown rock, blue rock and white rock. About one-fourth of the high grade Tennessee phosphate is ship- PHOSPHATES 75 ped to Europe the remainder being used in this country. The output of Tennessee phosphate has amounted to 5,315,422 tons from 1893 to 1908. The Tennessee rock phosphates are not in favor in Europe because of their high content of iron and alumina oxides, which run from 2 to 4.5 per cent. The brown rock has been sold more than the blue or white rock.* Canadian Apatite. — This is rock where the phosphate has be- come crystalline and is known as apatite and is found principally in the provinces of Ontario and Quebec. It is not mined very extensively, only 748 tons being produced for 1907. It is a variable product and contains impurities. The Canadian apatite carries from 75 to 90 per cent, of tricalcium phosphate, which is equivalent to 34 to 41 per cent, of phosphoric acid. Preparing Canadian apatite for the market is a more expensive operation than mining the American phosphates. Apatite is usually con- sidered one of the purest forms of tricalciiun phosphate for manufacturing fertilizers.* Rodunda Phosphate. — This i)hosphate is found on the Rodunda Island. It is not a phosphate of lime but a phosphate of iron and alumina. Although the per cent, of phosphoric acid is high, ( 20-38 per cent. ) this material cannot be used to manufacture into acid phosphate liecause of the absence of lime. The gypsum (sulphate of lime) formed in the manufacture of acid phosphate from phosphate of lime acts as a drier. Rodunda phosphate may be used for crops provided it is well pulverized but it must be considered as slow acting. This product is sometimes called iron and alumiiTa phosphate rock. Basic Slag. — This is known by several names as iron phosphate. Thomas phosphate powder, odorless phosphate, and phosphate slag. When phosphatic iron ores are used for the manufacture of steel by the basic process, an excess of lime is used which unites with the phosphoric acid and iron and forms a product known as basic slag. There is not much of this product manufactured in this country but the production is large in England, France and Germany. According to Wiley : The quantity of basic slag 76 FERTILITY AND FERTILIZER HINTS manufactured ip Germany in 1893 was 750,CX)0 tons; in England 160,000; in France 115,000, making the total production of central Europe about 1,000,000, a quantity sufficient to fertilize nearly 5,000,000 acres. During the year 1907, it is estimated that German agriculture made use of from 1,500,000 to 1,600,000 tons of basic phosphate slags. The total output of basic slag is undoubtedly not far from 2,000,000 tons. The total produc- tion of basic slag is therefore approximately one-half of that of crude phosphates.^ This product is sold in the form of an inpalpable powder which is black in color. The phosphoric acid in basic slag is often rated as valuable as the phosphoric acid in bone-meal. The composi- tion of this product is variable depending on the amount of phos- phoric acid in the iron ore, but it is possible to obtain this pro- duct containing 23 per cent, of phosphoric acid, but the lower grades are most common. It averages about 14.20 per cent, of phosphoric acid. On account of the large amounts of iron oxide present, it is not suitable for manufacturing artificial fertilizers.* Phosphatic Guanos. — These guanos are of the same origin as nitrogenous guanos. They are the excreta of sea fowls. Be- fore the phosphate deposits were discovered in the United States these guanos were imported into this country and used largely by the manufacturers. All of these guanos originally contained nitrogen. . However the nitrogen, soluble phosphates, and alkalies have disappeared by decomposition of organic matter and leaching of water, so that most of them only contain traces of nitrogen. The phosphoric acid is in the form of tricalcium phos- phate and insoluble in water. Some of these guanos contain too much iron and alumina oxides to manufacture profitably. They are not imported into the United States very much now, as many of the deposits are exhausted or else too expensive to compete with our native mineral phosphates.* It should be understood that there are many other phosphates used in other countries but they cannot compete with our mineral phosphates and therefore are not found on the American market. ' Wiley, Principles and Practice of Agricultural Analysis, Vol. II. PHOSPHATES 11 Classification of Phosphates. — From the foregoing it is shown that there are three classes of phosphates used for fertiHzing purposes. I Raw bone-meal I Steamed bone-meal Bone-black Bone-ash Bone tankage Dry ground fish I. Bone phosphates 2. Rock phosphates { I Florida South Carolina Tennessee 1 Land pebble River pebble Hard rock Land rock River rock Brown rock Blue rock White rock Apatite Rodunda phosphate Phosphatic guanos. 3. Basic slag phosphates. Of the bone phosphates, bone-ash is not found much on the Fig. 8.— The hog; one of the sources of bone phosphate.— Courtesy of the Wisconsin Exp. Station. American market and bone-black is usually acidulated (treated 78 FERTILITY AND FERTILIZER HINTS with sulphuric acid) before being appHed as fertilizer. The production of rock phosphates in the United States has almost entirely discouraged the importation of the mineralized or phos- phatic guanos. Form of the Phosphates. — The phosphoric acid in bone phos- phates and rock phosphates is in the form of tricalcium phos- phate. Bone phosphates are always as phosphate of lime while rock phosphates contain more or less impurities as iron, alumina and silica. It is customary to apply the name, "bone phosphate of lime," to the phosphate present in rock phosphates, although tricalcium phosphate is the correct name. The phosphoric acid in basic slag is not in the same form as in the other phosphates. It was formerly accepted that the phosphoric acid in basic slag existed as tetra-calcium phosphate, but HalP claims that the phosphoric acid is in the form of double phosphate and silicate of calcium Ca,(CaO) (POJXaSiO,. Availability of the Phosphates. — All of the phosphates are slowly available as plant food and practically insoluble in water. The phosphoric acid in phosphates is not entirely used the first year so that maximum crop returns cannot be expected im- mediately, but the continued use of phosphates give good results. For quick growing crops the phosphates are not always desirable. The phosphates from bones are perhaps more readily decomposed than the rock phosphates. There is more or less organic matter in bones which decays quite rapidly and attacks the phosphoric acid with which it is closely associated. In the rock phosphates there is no organic decay and the impurities as iron and alumina retard to a certain extent the fermentation and decomposition of the phosphoric acid present. Basic slag phosphate as shown by the statistics in this chapter, is used extensively in Europe. European experiments show that this material is of higher avail- ability than the insoluble bone and rock phosphates. The nature of the soil has a great deal to do with the avail- ability of phosphates. Soils in good tilth will disintegrate the phosphates more readily than those in poor physical condition. The sandy and gravel soils are liable to give poorer results than ' Fertilizers and Manures. PHOSPHATES 79 clay soils or soils containing considerable organic matter and potash. Organic matter tends to promote fermentations which attack the phosphates and make them available as plant food, and with the aid of potash, it tends to act upon the lime of the phosphates. The kind of crop also influences the rate of de- composition of phosphates. Some plants are more able to make use of the phosphoric acid of phosphates than others.* CHAPTER VIII. SUPERPHOSPHATES AND EFFECT OF PHOSPHORIC ACID. The phosphates mentioned in the previous chapter, with the exception of basic slag, are not always used in the raw condi- tion for fertihzing purposes, but are treated with sulphuric acid in the manufacture of commercial or artificial fertilizers to make the phosphoric acid available ; that is, to convert the phosphoric acid into forms that may readily be used by the plant as food. Manufacture of Super or Acid Phosphate. — The manufacturing of artificial fertilizers began some time after 1840 in which year Liebig, a German scientist, discovered that by adding sulphuric acid (oil of vitriol) to bones the phosphoric acid was made soluble. This discovery paved the way for the manufacture of commercial fertilizers which are sold in such large quantities to-day. Manufacturing Sulphuric Acid. — The manufacture of super- phosphate is rather tecTinical but a knowledge of this important industry may prove of interest. To begin with, the manufac- turer purchases pyrites or brimstone and phosphate rock. Py- rites is a compound of sulphur and iron and is obtained from Spain and mines in this country. The pyrites or brimstone are burned in. special burners and the sulphurous gases are mixed with nitrous gases obtained from nitrate of soda. These mixed sulphurous and nitrous gases are introduced into large high lead towers and then into lead chambers which are also large and high. Steam is introduced into the lead chambers, mixed with the gases and sulphuric acid is formed which falls to the bot- tom as a liquid. These lead towers and lead chambers are very costly. Making Superphosphate. — The manufacturer purchases phos- phates that contain sufficient tricalcuim phosphate to warrant profitable treatment. Phosphates that contain considerable im- purities as iron and alumina are avoided. The phosphate rock is broken into small pieces and then pulverized. Certain amounts, say 1,000 pounds, of phosphate powder and dilute sulphuric acid SUPERPHOSPHATKS AND EFFECT OF PHOSPHORIC ACID bl are thoroughly mixed together by special machinery and con- veyed to a pit where the mixture is allowed to remain until ready for shipment. Chemistry of the Process. — The phosphoric acid is in the form of tricalcium phosphate in phosphates, or three parts of lime are united with one part of phosphoric acid. When the sulphuric acid is added it attacks the phosphate and dissolves it, setting free two parts of lime (that were originally combined with the phosphoric acid) which unite or combine with the sulphuric acid forming superphosphate (one lime phosphate or mono-calcic phosphate) and gypsum (sulphate of lime). In other words the phosphoric acid in superphosphate is only combined with one part of lime as the remaining two parts of lime, with which the phosphoric acid was formerly combined, have been set free. From the above it is evident that superphosphate is made up of one lime (mono-calcic) phosphate and gypsum (sulphate of lime). Or the reaction is : (3CaO PjOj) ; 2(H,,OSO:,) (Ca02H20P,0-) f 2(CaOS03) Tricalcic phosphate Sulphuric acid Monocalcic phosphate Gypsum Phosphates of Lime. — In the phosphoric acid fertilizers used there are four different forms of phosphates of lime, all of differ- ent availability. These phosphates of lime are known as the in- soluble, soluble, reverted, and basic slag forms. 1. Insoluble Phosphoric Acid. — The most common form of phos- phate of lime is that which is found in bones, mineral phosphates, guanos, etc., and is called insoluble. The lime and phosphoric acid are combined as three parts of lime and one of phosphoric acid. This is called tricalcic, tribasic, bone phosphate and three lime phosphate. We may represent this form as follows: Lime C lyime < Phosphoric acid. Ivime ( This is the most insoluble form of phosphate of lime and is called insoluble phosphoric acid. 2. Soluble Phosphoric Acid. — When insoluble phosphate of lime is acted upon by sulphuric acid, two parts of lime are replaced by two parts of water and soluble phosphate of lime is formed. 82 FERTILITY AND FKRTILIZER HINTS This soluble phosphate is called super or acid phosphate and is a saturated compound. It is also known as monobasic, mono- calcic, and one lime phosphate. This compound may be graphically represented as : Lime i Water - Phosphoric acid. Water ( This form is entirely soluble in water and readily available as plant food. It is the highest valued form of phosphate of lime and is called soluble phosphoric acid. 3. Reverted Phosphoric Acid. — Between the soluble and in- soluble phosphate of lime there is another form known as re- verted, citrate soluble, dicalcic, and two lime phosphate, in which there are two parts of lime and one part of water as represented : lyime ( Lime - Phosphoric acid. Water ( The name reverted is applied to this form of phosphate of lime because it is formed by reversion or retrograding of some of the soluble towards the insoluble. This form is not as soluble as the soluble phosphoric acid and is more soluble than the in- soluble form. It is insoluble in water, but the weak acids of the soil render it favorable for i:)lant food. The sum of the soluble and the reverted is called ai'ailablr. because both forms may be used by plants. 4. Basic Slag Phosphate. — It used to be accepted that the three forms just described were the only forms of phosphoric acid. However, the phosphate of lime in basic slag is in another form. It was supposed that one part of phosphoric acid was combined with four parts of lime, and in this form it was known as tetra- calcic, tetrabasic, and four lime phosphate. Lime | Lime ! r>, , • • , J ■ { Phosphoric acid Inline I Lime \ Recently, however, there seems to be some uncertainty as to whether or not the phosphoric acid in basic slag exists as tetra- SUPERPHOSrHATES AND EFFKCT OF I'HOSPHORIC ACID S3 calcic phosphate of Hnie. HalF says it exists as double silicate and phosphate of lime (CaO),- PoOr.SiO.. Whatever may he the form of combination of the phosphoric acid in basic slag, it is easily attacked by soil water, and is more available than any of the forms of tricalcium phosphate, though usually less than superphosphate.* Value of Reverted Phosphoric Acid. — The value of reverted phosphate is a subject which has given rise to much dispute among chemists. That it has a higher value than the ordinary insoluble phosphate is now admitted, but in this country, (England) in the manure trade, this is not as yet recognized. At first it was thought that it was impossible to estimate its quantity by chemical analysis. This difficulty, however, has been overcome, and it is generally admitted that the ammonium citrate process furnishes an accurate means of determining its amount. Both on the con- tinent and in the United States reverted phosphoric acid is rec- ognized as possessing a monetary value in excess of that possessefl by the ordinary insoluble phosphates. The result is, that raw mineral phosphates containing iron and alumina to any apprec- iable extent are not used in this country (England), although they do find a limited application in America and on the conti- nent.^ * Difference Between Phosphates and Superphosphates. — It is cus- tomary among some farmers to call every fertilizer a phosphate and among others this name is used for the product — superphos- phate. A phosphate is a product containing phosphoric acid as its main ingredient, in the insoluble form, as bone phosphates, rock phosphates and basic slag phosphates. A superphosphate is a fertil- izer containing principally soluble phosphoric acid. The phosphates, except basic slag and Rodunda phosphate, may be manufactured into superphosphates by the addition of sulphuric acid as previous- ly mentioned in this chapter. Thus we have superphosphates from bones and minerals, as raw bone superphosphate, steamed bone superphosphate, bone-ash superphosphate, bone-black superphos- phate, Florida hard rock superphosi)hate, Florida pebble superphos- 1 fertilizers and Manures. 2 Akiman. Manures and Manuring. 84 FERTILITY AND FERTILIZER HINTS phate, Florida soft rock superphosphate, South Carolina land rock superphosphate, South Carolina river rock superphosphate, Ten- nessee brown rock superphosphate, Tennessee blue rock super- phosphate, Tennessee white rock superphosphate, etc. Of course all of these superphosphates will not contain the same amounts of soluble phosphoric acid, as the mode of manufacture and con- tent of phosphoric acid in the raw products determine this. A superphosphate made from bone-black containing 30 per cent, of phosphoric acid will be richer in soluble phosphoric acid than one made from South Carolina land rock running 23 per cent, of phosphoric acid. Bone-black and bone-ash because of their higher phosphoric acid contents make richer superphosphates than those manufactured from most of the mineral phosphates. Some Names Applied to Superphosphates. — Acid phosphate, dis- solved bone, dissolved bone-black and dissolved bone-ash are names that are used indiscriminately by the trade. A manufac- turer may call a product made from rock phosphate, "dissolved bone," and sell it under this name. Dissolved bone, strictly speaking, is dissolved bone superphosphate, or a superphosphate made from raw or steamed bones. Dissolved bone-black is a superphosphate manufactured from bone-black. Dissolved bone- ash is a superphosphate made from bone-ash. The superphos- phates made from rock phosphates are usually called acid phos- phates by the trade, although this latter term is applied to any superphosphate and is perhaps a more common name in the United States than superphosphate. For superphosphates made from ground rock phosphate, acid phosphate is perhaps a more correct name as it is the phosphate acted upon by acid. Available Phosphoric Acid. — There seems to be a great deal of confusion among farmers over what constitutes available phos- phoric acid and this is not to be wondered at when one con- siders the number of terms applied to reverted and insoluble phosphoric acid. Reverted phosphoric acid is soluble in the weak acids of the soil. The chemist uses a solution called ammonium citrate or citrate, which has a similar action to the weak soil acids, in dissolving out this form of phosphoric acid. For this reason the term citrate soluble is often applied to reverted phos- SUPERPHOSPHATES AND EFFECT OF PHOSPHORIC ACID 85 phoric acid. The insoluble phosphoric acid is not soluble in this citrate solution but it is soluble in strong acids, hence the names citrate insoluble and acid soluble are applied to insoluble phos- phoric acid. Reverted phosphoric acid is equivalent to citrate soluble phosphoric acid. r iui 1. u- J- -14^^ ( citrate insoluble phosphoric acid Insoluble phosphoric acid IS equivalent to 4 Phosphoric acid in fine ground bone and tankage t^}^ Phosphoric acid in coarse bone and tankage 3 Phosphoric acid insoluble (in water and in ammonium citrate) in mixed fertilizers 2 Potash as high grade sulphate and in mixtures free from muriate f chloride) 5 Potash as muriate 4X Vermont Experiment Station. 124 FERTILITY AND FERTILIZER HINTS How Obtained, — To give an idea of how these trade values are obtained v^e may presume that the wholesale price of sulphate of ammonia for the six months preceding March ist averaged $56.80 per ton, or 14.2 cents a pound for the nitrogen. A cer- tain amount, usually 20 per cent, is added to this wholesale price to cover the cost of handling, insurance, etc., which would raise the price to $68 per ton, which would be the retail or commercial value of ammonium sulphate. The nitrogen then would be represented as carrying a commercial or trade value of 17 cents a pound. The trade values on all other fertilizer materials are calculated in the same way as described for sulphate of ammonia. A Discussion of the Table of Trade Values. — A study of the table is interesting. It shows that valuations are given for nitrogen as nitrate, as ammonia and as organic nitrogen. The trade values for organic nitrogen are also different depending upon the source. Soluble phosphoric acid is valued higher than reverted phosphoric acid and there is also a trade value for in- soluble phosphoric acid. In some states there is no distinction made between soluble and reverted phosphoric acid in trade valuation and the insoluble phosphoric is often not considered at all. The bone products in the foregoing table are valued on their degree of fineness ; the finer bone-meals command higher market prices than those that are coarse as is shown in the trade valua- tions of nitrogen and phosphoric acid. The potash as sulphate carries a higher trade value than potash as chloride, but this is to be expected because sulphate of potash costs more to manu- facture than muriate of potash. There are many fertilizer materials not included in the above table. Those included in the table are high class products commonly used in New England and New Jersey. How to Calculate the Commercial Value of a Fertilizer. — Let us suppose a chemist analyzes a mixed fertilizer and finds its com- ])osition to be as follows : VALUATION OF FERTILIZERS 1 25 Chemicai, Analysis. Per cent. Nitrogen as nitrates 0-5o Nitrogen as ammonia ' -S"^ Nitrogen as organic 2.00 Water soluble phosphoric acid 6.00 Phosphoric acid soluble in ammonium citrate (reverted) 1.80 Phosphoric acid insoluble (in water and ammonium citrate) ' -So Potash as sulphate o-4o Potash as chloride 3-oo The commercial valuation of the ahove fertilizer would be ob- tained by multiplying each ingredient by 20 to change to a ton basis, and multiplying this product by the trade value of each. The sum of these values would be the total commercial value as derived from the raw products. Commercial Valuation. Pounds Trade Coninier- per 100 Pound.s value cial value or per. per per lb. per cent. ton cent.s ton Nitrate nitrogen 0.50X20= 10 X 16.5 = |i-65 Ammonia nitrogen 1.30X20= 26X17 = 4-42 Organic nitrogen 2.00X20= 40X19 = 7-6o Soluble phosphoric acid 6.00 X 20 = 120 X 4 = 4-8o Reverted phosphoric acid 1.80 X 20 = 36 X 3-5 = 1-26 Insoluble phosphoric acid 1.50X20= 30 X 2 = 0.60 Potash as sulphate 0.40 X 20 = 8X5 =• 0.40 Potash as chloride 3.60X20= 72 X 425= 3-o6 Total commercial value* = I23.79 CHAPTER XIV. HOME MIXTURES. Definitions. — When fertilizer materials such as tankage, dried blood, nitrate of soda, sulphate of ammonia, superphosphate, bone meal, muriate of potash, etc.,_^are purchased and mixed at home the process is called home mixing and the product a home mix- ture. When these fertilizer materials are mixed by the factory the product is called a fertilizer or a mixed fertilizer. Most of the fertilizer materials contain either one or two constituents and only a few carry all three constituents. Most of the mixed fertilizers contain three constituents, namely, nitrogen, phosphoric acid and potash and are called complete fertilizers because they contain the three essential elements. There has been a great deal of discussion as to whether fertilizer materials or mixed fertilizers are the best for the consumer to purchase. Manufacturer's Claims. — The manufacturers claim that mixed fertilizers are the best for the farmer to purchase because : 1. The factory mixed fertilizers are in a fine mechanical con- dition. The mixed fertilizers are ground fine and uniformly mixed, which is indeed an important consideration to permit of an even distribution on the land. 2. The mixed fertilizers can generally be purchased in the locality at most any time and in any amount. 3. The mixed fertilizers are specially treated with acid and the constituents in substances like tankage, dry ground fish, etc., are made partially available. 4. The mixed fertilizers are claimed to be made up in such proportions as to satisfy the needs of crops. 5. The manufacturers often allow the farmer some time to settle and often wait until harvest time before getting their money. The credit system is in vogue in the South where enormous quantities of mixed fertilizers are used. Reasons Why the Farmer Should Mix Fertilizer Materials at Home. — The mixing of fertilizer materials at home is becoming home; mixtures 127 more popular among the farmers. Some of the reasons why the farmer should mix his own fertilizer materials follow : 1. Plant food is obtained at a lower price. 2. The farmer knows the materials used. 3. Unnecessary constituents are not purchased. Mechanical Condition of Factory and Home Mixed Fertilizers. — The factory mixed fertilizers are usually much better mixed than those that are mixed at home. Fertilizer factories are well equipped with special machinery to insure producing a uni- form product that may easily be distributed on the farm. How- ever, the careful farmer may mix his fertilizer materials uniformly enough for all practical purposes. Mixed Fertilizers More Easily Purchased. — Mixed fertilizers can generally be purchased in the locality and the raw materials must be ordered away from home which of course takes some time. Sometimes certain raw materials are hard to obtain. If the farmer starts early enough, say in the winter, the raw materials can generally be obtained. Mixed Fertilizers Compounded for the Needs of the Crop. — When a manufacturer makes up his formulas he has to allow for the general existing conditions of soil, climate, and needs of the crop, and he cannot expect to make a particular brand that will suit each farmer's requirements. When he makes up a potato brand he must make a mixture that will suit most of the farmers growing potatoes and he cannot expect to meet every condition of soil. Manufacturers Often Allow Credit. — On the whole, the credit system is a poor system for the farmer, for when his crop is made he may or may not be ahead financially. Those that live on the credit system are usually a year behind and two or three poor crops results in the loss of the farm. The manufacturers, however, are often too lenient in selling their mixed fertilizers on the credit basis as they often have large losses which take away much of their profit. Plant Food is Obtained at a Lower Price in Home Mixtures. — The work of the Experiment Stations has proved conclusively 128 FERTIUTY AND FERTILIZER HINTS that plant food is obtained at a lower price when the fertilizer materials are purchased and mixed at home than when mixed fertilizers are employed. Of course in using home mixtures, freight on fillers is saved.* Home Mixing Acquaints the Farmer with the Materials Used. — When a farmer buys a factory mixed fertilizer he does not always know just the sources of the nitrogen, phosphoric acid and potash. He may desire his potash wholly as sulphate ; he may want a part of his nitrogen as nitrate and a part in the organic form from dried blood. When he buys factory mixed fertilizers he has to take the word of the agent or the manufacturer. Most manu- facturers are honest men who give what is asked for but when you mix at home you know just the amount and kind of materials you are using. Again, when you mix your own fertilizer materials you deal in the subject "plant food," that is, so much nitrogen, so much available phosphoric acid and so much potash, and you do away with your old bad habit of purchasing fertilizer for a given amount per ton regardless of its plant food value. Home Mixing Does Away with the Purchase of Unnecessary Constituents. — Manufacturers make many brands of fertilizers but as previously said they cannot make one brand that will suit the requirements of every individual farmer. For example, two farmers in the same locality wish to purchase a mixed fertilizer for their corn. One of these farmers may have applied farm manure or he may have plowed under a leguminous crop, while the other farmer has not supplied his soil with any organic matter and his soil may be poor and in need of humus. The fertilizer agent or merchant in this particular locality is selling a corn fertilizer guaranteed to contain nitrogen, phosphoric acid and potash in stipulated amounts. Is it reasonable to suppose that this one brand of corn fertilizer is the best fertilizer for both soils under the above conditions? The first farmer who has supplied farm manure or plowed under a leguminous crop would be wasting money in purchasing nitrogen, unless a little in the form of nitrate, which may help to give the crop a start. The other farmer would need a fertilizer containing both nitrogen as HOME MIXTURKS 129 nitrate and nitrogen in some desirable organic form to help pro- duce a crop. Again, a farmer may be growing cotton, corn, sugar-cane, etc., on a soil that is very rich in available potash. Fig. II.— Corn is a crop that thrives on farm manure. It would certainly be a waste of money for him to purchase a fertilizer containing potash. 130 FKRTILTTY AND FERTILIZER HINTS When home mixing is practiced the farmer can purchase those fertiHzer materials that supply the needed constituents and in the most desirable forms for the needs of his soil and crop. How to Purchase Fertilizer Materials — The large consumer should certainly try home mixing and find out its advantages. The small farmer may find it impracticable to purchase other than factory mixed fertilizers. However, several small consum- ers may often advantageously club together and purchase fertilizer materials in mixed carload lots. Many manufacturers will gladly mix fertilizer materials for the farmer when the order is large enough. Of course the farmer must know just the amounts and kinds of materials he wishes wlien he orders in this way. To purchase fertilizer materials to mix at home, it is necessary to start early, say in the early winter, so that they may be mixed before the heavy spring work starts. Quotations should be secured from dififerent parties in the nearest or nearby fertilizer markets. In most large cities bids can be secured. Be ready to pay cash because these raw materials are not usually sold on credit. Buy on the guarantee and if the constituents, nitrogen, phosphoric acid and potash fail to reach their guarantees de- mand a rebate. This can be easily arranged by making a con- tract with the manufacturer or broker. How to Mix Fertilizer Materials at Home. — The fertilizer ma- terials may be mixed in a wagon box, or better, on a tight barn floor, or a floor covered with canvas. Whenever chemicals as nitrate of soda, potash salts, etc. are used, they should be well broken up and rendered as fine as possible. In mixing, the light bulky materials as dried blood, cotton-seed meal, dry ground fish, etc., should be put on the bottom of the floor and on top of these spread the other materials. The materials should be spread even- ly and then turned over and over and thoroughly mixed by shovel- ling. It takes considerable time to mix fertilizer materials so that the mixture is uniform. After the mixing is completed the fertilizers should be bagged and kept in dry storage until ready for use. If the mixture predominates in concentrated salts, some HOMI-: MIXTURKS I3I t-arth ina\- he incorporated to insure a more even mixture. It should be remembered that the chief advantage of buying factory mixed fertihzers is that they are better mixed and tlie farmer cannot spend too much time in tlie process of thoroughly mixing his fertilizer materials.* How to Calculate Percentages from Known Amounts. — Suppose you want to fmd out the analysis of a mixture made up of the following : Mixture. 600 lbs. acid phosphate analyzing 14 Jo available phosphoric acid 150 lbs. snlphate of ammonia analyzing 20 % nitrogen 100 lbs. sulphate of potash analyzing 50 fc potash. 850 lbs. Total. To find out the number of pounds of available phosphoric acid, nitrogen and potash in the above mixture, make the following multiplication. 6 X 14 = 84 lbs. available phosphoric acid 1.5 X 20 = 30 lbs. nitrogen I X S*-* = 50 lbs. potash, To calculate the percentages of available phosphoric acid, nitrogen and potash, divide the amounts of the constituents by the total amount of the mixture. Available phosphoric acid, lbs. 84 :- 850= 9.88 % available phosphoric acid Nitrogen lbs. 30 -^ S50 = 3.53 % nitrogen Potash lbs. 50 -T- 850 = 5.88 % potash. If percentages are wished when one of the materials contains two constituents, the calculations may be made as follows : Mixture. 200 lbs. dissolved bone analvzing \ '^ t' available phosphoric acid ** I. 2.5 % nitrogen 100 lbs. nitrate of soda analyzing 18. 84 % ammonia 50 lbs. carbonate of potash analyzing 64.00 % potash. 350 lbs. Total. The dissolved bone superphosphate furnishes two constituents, available phosphoric acid and nitrogen, so we must take these into consideration in our calculations. 132 FERTILITY AND FERTILIZER HINTS The nitrate of soda is given as carrying an equivalent of 18.84 per cent, of ammonia. To convert ammonia into nitrogen we must multiply by the factor 0.823. 18.84 fc ammonia -J 0.823 -" i5-5 % nitrogen. Then : 2 X 15 ^= 30 o lbs. available phosphoric acid 2 X 2.5 = 5.0 lbs. nitrogen from dissolved bone superphosphates ' X 15-5 = 15-5 lbs. nitrogen from nitrate of soda 0.5 X 64 = 32.0 lbs. potash. The percentages in this mixture would be : Available phosphoric acid lbs. 30 -r- 350 ^= 8.57 Jr available phosphoric acid Nitrogen lbs. 20.5 -^ 350 = 5.85 % nitrogen Potash lbs. 32 -^ 350 = 9. 14 % potash. How to Calculate Amounts from Known Percentages.^If 2,000 pounds of a mixture analyzing Available phosphoric acid 7 per cent. Nitrogen 5 per cent. , and Potash 6 per cent. is desired from Acid phosphate analyzing 16 % available phosphoric acid. Calcium cyanamid '" 17 % nitrogen, and Muriate of potash " 50 'r potash. it may be calculated in the following way : First find out the number of pounds of available phosphoric acid, nitrogen and potash that would be required. Since 2,000 IS 20 times 100 we may mtdtiply the percentages by 20. 20 X 7 ( >^ avail, phos. acid) — 140 lbs. avail, phos. acid required for 2,000 lbs. 20 X 5 ( ^ nitrogen) = 100 lbs. nitrogen " " " " 20 X 6 ( %> potash ) == 1 20 lbs. potash " " " " To determine the number of pounds of acid phosphate, calcium cyanamid and muriate of potash needed to give the analysis desired, we may divide the pounds of available phosphoric acid, nitrogen and potash by the percentages that the materials analyzed. Avail, phos. acid lbs. 140 -^ i& 'r := S75 lbs. acid phosphate required Nitrogen " 100 ^ 17 % = 5S8 lbs. calcium cynamid required Potash " 120 -7- 50 'r ■= 240 lbs. muriate of potash required Total = 1 ,703 lbs HOME MIXTURES 133 We have only 1,703 pounds and not 2,000 pounds the amount desired. To make 2,000 pounds an addition of 297 pounds of some make weight material as sand, earth, gypsum, etc., is necessary. Supposing' we wished to substitute kainit, analyzing 12 per cent, of potash, for the muriate of potash in the above mixture. By calculating as explained above we find that it would require 1,000 pounds of kainit to analyze 6 per cent, of potash. This amount would make our total add up to 2,463 pounds, or 463 pounds more than we wish. This shows that kainit could not be used to supply all of the potash in a 2,000 pound mixture of the above analysis made from such materials. We could however supply one-third of the potash from kainit and two-thirds from muriate of potash. Potash lbs. from kainit 40 -^ 12 % == 333 lbs. kainit Potash lbs. from muriate 80 -^- 50 % = 160 lbs. muriate of potash. Assembling the potash salts, acid phosphate and calcium cyan- amid we have : Pounds Acid phosphate S75 Calcium cj^anamid 58S Kainit 333 Muriate of potash 160 Total 1 ,956 By using kainit and muriate of potash in the above proportions only 44 pounds of filler would be necessary to add to make 2,000 pounds. "*' CHAPTER XV. A FEW REMARKS ABOUT FERTILIZERS. Brand and Trade Names. — There are too many farmers who purchase fertihzers on the brand or trade name and not on the plant food these fertihzers contain. The manufacturers are well acquainted with the importance of selling their fertilizers under attractive names. Some of the manufacturers even go so far as to have their brand names copyrighted to prevent their com- petitors from using them. Some of the older brand or trade names are well known by all the farmers in the locality Vv'here they have been sold from year to year and many of these farmers purchase Dixie Cotton Fertilizer, Great Western Wheat Fertili- zer, Home Mixture, Standard Special Tobacco Manure, Cele- brated Potato Fertilizer, Royal Corn Special, etc., from year to year without ever knowing their plant food content. The name sounds good to these farmers, the fertilizer has a good strong odor, the right color, and with some farmers the proper taste. These are brand and ton farmers and not plant food farmers. These farmers will tell you that their fathers used these same fertilizers. To show that the name is no indication of the composition and suitableness of a fertilizer for a crop, the following data is sub- mitted. In the state of Massachusetts for the year 1909, out of 66 brands sold as potato fertilizers, 46 contained potato as the only crop name, and 20 were sold in conjunction with other crop names as potato, hop, and tobacco ; potato and root crop : potato and tobacco ; potato and vegetable ; corn and potato ; potatoes, roots and vegetables ; onion and vegetables. Twelve com- panies put out 2 brands, 5 put out 3 brands, and 3 put out 4 brands. The nitrogen guaranteed varied from 0.80 to 3.71 per cent., the available phosphoric acid from 4 to 9 per cent., and the potash from 2 to 10 per cent. All of these potato fertilizers could not have been the best for the farmer to purchase. The manu- facturers evidently cater to the trade and some of them put out 2 to 4 brands so as to be able to sell one of them to the farmer, A FEW REMARKS ABOUT FKRTILI/KRS 135 the brand depending upon the price the farmer is willing to pay. Many of these fertilizers were high grade but the farmer should consult the plant food guarantee and not the name in selecting fertilizer. Those that were sold for corn and potato, tobacco and potato, vegetables, root crops antl potatoes, etc., either do not meet the requirements of these crops, or else the purchaser is wasting money in buying excesses of ])lant food. Some manufacturers ])ut out two or three different brands made from the same goods and guaranteed the same. Thus we will find Dixie Cotton Fertilizer and Corn King Guano on t\vj market with the same guarantee bagged from the same pile of goods, and sold for different crops. Sometimes two different brand names are used for the same material to be sold for one crop. For example. Golden Imperial and Special Mixture may be sacked from the same material, carry the same guarantee, and be sold for one crop. The writer has seen two agents, one a merchant and the other a farmer, selling the same fertilizer under diff'erent names in the same village. The farmer, who was the least suc- cessful in disposing of his lot thought and 1 guess still thinks that the merchant had a better brand. These fertilizers of course sold for the same price and the merchant sold three times as much as the farmer, because he was a bit more ])opular and had a better stand. So you see the brand name helps to sell fertilizer. The farmer should buy on the plant food content and not by the name or per ton. The manufactm-ers also often sell sui)erphosphates made from rock phosphates under the name of dissolved bone, and mixtures of superphosphates (made from rock) and potash, as dissolved bone and potash. We have learned that dissolved bone contains nitrogen and phosphoric acid and superi)hc)sphates made from rock only carry phosphoric acid. So when dissolved bone or a dis- solved bone and potash are sold w'ithout any nitrogen guaranteed you can rest assured that the material was made from rock. However, the soluble phosphoric acid from rock superphosphates is just as valuable as that from dissolved bone, and the reverted is perhaps about eciually valuable from these two phosphates.* 136 rKRTILlTY AND FERTILIZER HINTS How to Purchase a Fertilizer. — Some time before you intend to purchase your fertilizer write to your Experiment Station or State Board of Agriculture for bulletins on the crops you in- tend to raise and also for a fertilizer bulletin. These bulletins may be had free of charge. Study these bulletins. In the bulletins on crops you will no doubt learn the plant food reqaire- ment, that is, the amounts and kinds of plant food most suitable for the crops you are interested in. The fertilizer bulletin will no doubt acquaint you with some timely suggestions on how to purchase fertilizers and will also give you the names, guarantees, analyses, and valuations of the fertilizers sold in your state. You can in all probability select a fertilizer that will meet your requirements. If any element as nitrogen, phosphoric acid, and potash is not needed, do not waste your money by purchasing a complete fertilizer but select one that contains the constituents you need and in the form or forms you desire. You are now ready to talk business with your merchant or dealer. Find out from him if he has the particular fertilizer you wish. Perhaps he has not it in stock and he will no doubt tell you he has some- thing just as good. ]f the amount and kind of plant food that you wish is present in the brand that he has, why it is just as good and if not it is not what you want. No doubt the factory for which he is agent puts out a fertilizer of the composition you desire ; you can find this out by referring to your fertilizer bulletin. If so, you may be able to get your merchant to order it for you. If his factory has not got it buy from one that has. You have your fertilizer bulletin and you can easily write for your fertilizer and perhaps save the agent's profit. Study the Guarantee.— ^'ou have learned that many of the fertilizer materials as cotton-seed meal, tankage, bone-meal, dry ground fish, etc., do not always contain the same amounts of fertilizer constituents and are quite variable in composition. Therefore do not buy any of these products just because they are so named. Consult the guarantee and find out how much plant food is offered for a certain price.* Fertilizers Should Reach their Guarantees. — The manufacturers, A FEW REMARKS ABOUT FERTILIZERS I37 as a whole, are endeavoring to do an honest business. In mak- ing their mixtures they aim to give a little more plant food than they guarantee, so that the fertilizer will meet the guarantee under reasonable conditions. The bulletins of the different states setting forth the results of fertilizer inspection, show that the majority of the factory mixed fertilizers exceed the guar- antee. But sometimes fertilizers fail to reach the guarantee in all constituents. Factory mixed fertilizers often fall below the guarantee in one element but exceed the guarantee in other elements so that the relative value is above the guaranteed value. Of course the manufacturer should furnish the consumer with fertilizer that reaches its guarantee in all elements as the pur- chaser has a right to expect this. Such variation is often due to poor mechanical mixture as the manufacturer usually puts in enough of the raw materials to exceed the guarantee in all constituents. When a shipment of fertilizer fails to meet its guarantee in one or more elements, and runs above the guarantee in one or more elements, the purchaser should give the manu- facturer some consideration and settle on an equitable basis and allow the manufacturer for whatever excess that may be present in any of the elements, within reasonable limits. If the purchaser contracts for a certain amount or amounts of con- stituents and they fall materially below the guarantee a rebate should be demanded.* Fertilizers do not Deteriorate Much on Standing. — The mixed fertilizers and the raw materials do not change much when kept in dry storage. The mixed fertilizers are usually com- pounded from materials that do not attack and set free the nitrogen present. The soluble phosphoric acid may revert and change to insoluble phosphoric but not to any appreciable ex- tent. Therefore should a farmer have some fertilizer left over from a past season he may rest assured that it is still valuable provided it has been kept in a dry place. If fertilizer gets wet from rain or becomes very moist from any cause, there may be considerable losses of plant food.* The Time to Apply Fertilizer. — Nitrate of soda, sulphate of 138 FERTILITY AND FERTILIZER HINTS ammonia, and calcium nitrate are soluble in water and are not fixed in the soil. They should be applied in small quantities and at the proper time, or when nitrogen is needed, to give the best results. When large applications of these materials are made, some of the nitrogen may be lost by leaching. These fertilizer materials should never be worked into the soil too deeply as they may be lost by leaching before the plant can appropriate them. The organic materials furnishing nitrogen all have to be oxidized and converted into nitrates before they may readily be acquired as plant food. These materials may be applied early enough so that they may be acted upon by the soil organisms and partially decomposed to furnish food for the young plant. The very slowly available organic substances will of course be decomposed more slowly than dried blood, cot- ton-seed meal, tankage, steamed horn and hoof meal, castor pomace and similar substances. One of the functions of nitro- gen is to produce growth. It would be wasteful to apply any nitrogenous substance to hasten maturity. It seems almost un- necessary to make this statement but some farmers use nitrate of soda late in the season to help fill out ears of corn after the crop has been made. If nitrate of soda is added in the middle of the growing period before the ears are formed it will help to produce more vigorous growth. Generally speaking, the nitrog- enous fertilizers may be applied in the spring at planting time and during the growing period when needed. Phosphoric acid is readily fixed in the soil. When soluble phosphoric acid is added from superphosphates, it becomes well distributed in the soil, because of its fine mechanical condition, and changes to insoluble forms which are not apt to be lost by leaching. Superphosphates are very beneficial to young crops and tend to produce strong plants that can better resist the attacks of fungi and insects. Superphosphates may be applied before or during planting time. Raw bone-meal and ground rock phosphate may be applied at most any time because they are slowly available ; but other fertilizers carrying phosphoric acid in the available form should be applied just before, or at planting time. A FliW REMARKS ABOUT FERTILIZERS I39 Potash is very (|uickly fixed in the soil by the double silicates, so that it is difficult to distribute it evenly. Potash may be applied sometime before planting so that the plowing and har- rowing may help to mix it with the soil and insure a uniform distribution. In mixed fertilizers we have found that any combination of fertilizer materials may enter into their composition. There may be nitrate of soda, organic materials, superphosphates, and potash salts present in these fertilizers and so in the application of them we must consider the properties of all the fertilizer materials. It is generally best to apply these fertilizers in the spring. Sometimes an additional application during the grow- ing period will help to force the crop. When much fertilizer is to be applied, especially on sandy soils, part of it may be applied in the spring and part later on when the crop may be backward or need forcing. Crops like wheat which are sown in the fall need fertilizer at that time and also a light dressing of some nitrogenous fer- tilizer in the spring to help it recover from the winter. Some of the market garden crops require fertilizer at planting time and at sht^-t intervals during the growing period. How Fertilizers are Applied. — Fertilizers are usually broad- cast, partly broadcast and partly in the drill or hill, and in the drill or hill. When heavy applications are applied, broadcast- ing is perhaps the best "method. The fertilizer may be applied after the last plowing and harrowed into the top part of the sur- face soil with a wheel harrow or some kind of a cultivator. In this way the fertilizer will become well mixed with the soil. If a broadcast distributor is not used, one-half of the fertilizer may be applied by walking north and south and the other half by walking east and west. In this way the fertilizer should be uniformly applied. When home mixtures containing farm manure or fertilizers mixed with manure are used, the manure spreader may be employed to distribute the fertilizer. Some farmers apply fertilizer partly by broadcasting and part- ly in the drill or hill. This is an excellent practice for some I40 FERTILITY AND FERTILIZER HINTS crops and on some soils. That which is appHed in the drill or hill furnishes plant food during the first growth before the roots are developed and that which is sown broadcast helps the later growth when the roots spread out. In this system of applying fertilizers it is perhaps better to apply most of the fertilizer broadcast. When farm manure is used it may all be spread broadcast and the fertilizer used to supplement it, which is no doubt quick acting, put in the drill or hill. Potatoes, corn and market garden crops are often fertilized in this way. With small grain, roots and other crops with small root systems, fertilizers are often applied wholly in the drill or hill. Great care should be taken in applying fertilizer in this way to keep the fertilizer away from the seed. Most fertilizers contain some nitrate of soda, potash salts, or other materials that will injure the seed if they come in contact with it. Therefore a little earth should separate the seed from the fertilizer. The fertilizer distributors usually cover the fertilizer sufficiently to protect the seeds. When fertilizer is applied in the hills it should be spread over the place where the hill is to be and not applied all in one place. Earth should be spread over it as in drill application. When fertilizer is to be applied during the growing season it may be distributed on both sides of the plants to the center of the row and worked in with a cultivator. On many hoed crops this method is used. It is also advisable on light soils that are subject to leaching. On these soils sufficient fertilizer may be applied at planting time to give the crop a start and the remainder during those periods in the growing season when the crop needs nourishment or wishes to be forced for an early market. When fertilizers are applied to trees and bvishes they should be distributed in a circle around the tree ; the radius of which is equal to the height of the tree or bush. They should be worked into the soil by shallow cultivation. The feeding roots of many trees are near the surface and extend to quite a dis- tance from the base of the tree so that by applying the fer- A FEW REMARKS ABOUT FERTILIZERS 141 tilizer for some distance from the tree, the roots are better able to assimilate it and the soil organisms which render it avail- able can act upon it more readily. It is Profitable to Use Fertilizers? — Every farmer should be able to decide this question for himself. The nature of the crop and the condition and fertility of the soil will determine whether fertilizers should be used. If extensive farming is •Fig. 12.— Liberal fertilization is usually profitable when growing truck crops. practiced and large crops are grown on small areas fertilizers are generally required. Market garden and truck crops general- ly more than pay for the liberal use of fertilizer. When market garden and truck crops are grown on high priced land large applications of fertilizer are necessary to produce ma.ximum crops to insure profitable returns on the investment. In some sections potatoes, onions, tobacco, oranges, and other crops re- ceiving large amounts of fertilizer give profitable returns. 142 FKRTILITY AND FERTILIZER HINTS If the soil is kept in good physical condition the use of ferti- Hzers is more profitable than on soils not properly cared for. On poor soils the use of fertilizers is necessary for crop pro- duction, for without them a profitable crop cannot be produced. On farms where a systematic rotation is practiced, and farm manures and green manures are employed, the use of fertilizer to supplement the deficiencies of the soil is usually very pro- fitable, while on farms where one crop farming is continued, the response to fertilizers is not so satisfactory. The farmer can keep his soil in good condition and profit by the use of fertilizers. Fertilizers should not always be blamed for unprofitable re- turns as the trouble generally rests with the farmer who is care- less in his methods. Farmers should spend a great deal of time tilling the soil and not expect the fertilizer to do all the work. Sometimes fertilizers do not prove profitable because the soil is acid or too alkaline. If these conditions are corrected the use of fertilizers is often profitable. It should be remembered that some fertilizers like raw bone- meal, ground rock phosphate, etc., do not give up all of their plant food during the first season but may help the crops for two or three years and prove profitable in this way. Amount of Fertilizer to Use. — Enough fertilizer should be used to produce profitable crops. This amount depends upon a great many factors, as the system of farming, the nature of the soil, the crop to be raised and its value, the fertility of the soil, the value of the land, etc. Frequent light applications are usual- ly more profitable than occasional heavy applications. Market garden and truck crops require more fertilizer than the staple crops. From 500 to 2,500 pounds of fertilizer are used for market garden, truck and special crops, and 300 to 1,000 pounds for the staple crops, unless previous experience has shown that more or less than these amounts are necessary and profitable. The following table shows in pounds per acre the quantities of the elements suggested for use in available form, in fertilizers for the crops indicated.* Crops Nitrogen Phosphorus- j Potassium- Alfalfa 5-IO Apples ! 8-16 Asparagus 20-40 Barley 1 2-24 Beans \ S""-' Beets 20-40 Blackberries I 15-30 Buckwheat 15-3" Cabbage j 40-80 Carrots j i5-3" Cauliflower 40-80 Celery ' 40-80 Cherries ] 10-20 Clover 5-10 Corn 10-20 Cucumbers 30-60 Currants 10-20 Egg plant 40-80 Flax 1 0-20 Gooseberries io-2t) Grapes 8-16 Grass for pastures 1 5-30 Grass for lawns 20-40 Grass for meadows 1 5-30 Hops I 20-40 Horse-radish \ 1 5-30 Lettuce 4080 Millet 15-30 Muskmelons 1 30-60 Nursery stock 1 0-20 Oats ; 12-24 Onions I 45-9" Parsnips ! 20-40 Peaches | 15-30 Pears ! 8-16 Peas I 5-10 Plums i 10-20 Potatoes 30-60 Pumpkins ; 30-60 Ouinces 8-16 Radishes ! 1 5-30 Raspberries 1 2-24 Rye 12-24 Sorghum i 10-20 Spinach \ 15-30 Squashes I 30-60 Strawberries 25-50 Tobacco ; 30-60 Tomatoes ! 25-50 Turnips 20-40 Watermelons 30-60 Wheat 12-24 12.5-25 12.5-25 12.5-25 8.5-17 12.5-25 jo-20 12.5-25 12.5-25 30-60 15-30 30-60 20-40 15-30 12.5-25 15-30 20-40 IO-2t> 20-40 10-20 10-20 12.5-25 12.5-25 10-20 12.5-25 15-30 10-20 20-40 12.5-25 20-40 10-20 8.5-17 25-50 25-50 17-5-35 12.5-25 12.5-25 i5-.iO '7-5-35 20-40 I 2 5-25 15-30 17.5-35 8.5-17 15-30 25-50 20-40 25-50 20-40 15-30 10-20 20-40 8.5-17 30- 60 40- 80 3 30- 60 75-150 25- 50 30- 60 35- 70 3(^1- 60 25- 50 30- 60 So- 1 60 30- 60 60-120 30 60 5()-i(.)o 25- 50 25- 50 70-140 40- 80 45- 90 40- 80 30- 60 35- 70 55-110 50-100 40- 80 35- 70 50- I 00 25- 50 25- 50 35- 70 50-100 60-120 60-120 30- 60 30- 60 50-100 io- 20 ' Bui. 169, Kansas Experiment Station. - To change phosphorus to phosphoric acid multiply by 2. to potash, multiply by 1.2. and to convert potassium 144 rERTILITY AND FERTILIZER HINTS NOTES. The following notes refer to tables, experiments, statistics, discussions and other interesting data that may be found in Halligan's Soil Fertility and Fertilizers : Page 3 — A discussion on evidence to show that other plants gather nitro- gen from the air. Page 5 -Distribution of elements in the earth's crust and air ; composition of the air. Page 8 — Table showing the elements that make up plants. Page 9 —The distribution of the mineral elements in plants and a full dis- cussion of the ash in plants. Page II — The per cent, of ash and the mineral elements that constitute the ash are given for several vegetable substances. Page 14 — Table of the amount of plant food in typical American soils from different states. Page 15 — Estimates of plant food in soils with yields of crops. Page 18 — Table of temperatures of different classes of soils. Page 18 — The average mean monthly range in temperature of the air and soil for twelve years at Lincoln, Nebraska. Page 18 — Standard measurements of soil particles and mechanical analyses of soils. Page 19 — Table of chemical and mechanical composition of different types of soils. Page 21 — Table showing the upward movement of water in different types of soils. Page 22— A table showing the number of bacteria found in a gram of soil during some part of the growing period. Page 22— Two tables that demonstrate how manure helps nitrification at different periods of the growing season. Page 26 — Composition of drainage waters from plots of a wheat field. Page 26- -Table giving the amounts of nitrogen removed by different farm crops. Page 27 — Data showing the amount of nitrogen lost from bare soils and wheat land ; comments on the same. Page 34 — Data concerning the effect of a rotation of crops on the humus supply. Page 34 — Crop rotations practiced in different sections of the United States. Page 34— Fertility removed by farm produce ; loss of fertility by exclusive grain farming and stock farming. Page 36— Tables showing actual results obtained from different kinds of animals performing different kinds of work on the value of manure. Page 36 — Composition of straws, leaves and sawdust. NOTICS 145 Page 37 — Data given the amount of manure produced by the horse per year, the composition, and the amount of straw necessary to absorb the liquid portion. Also data on the amount of manure produced by the cow and the hog, and the composition of these manures. Page 38 — The amount of manure produced by the sheep per year, its com- position, and the amount of straw necessary to absorb the liquid portion. Page 39 — Composition of hen, fowl and bat manures ; amount of manure produced by different kinds of fowl. Page 39 — Experiments by feeding steers different feeds, giving the varia- tions in the nitrogen content of the manure produced and the crop returns from these manures. Table and discussion on the commercial value of manure. Page 40— Results of experiments on the lasting effects of manure for a period covering many years and the jield of crops from manured and unmanured plots. Page 41— Tables and data showing the losses by leaching on horse manure, cow manure, and a mixture of horse and cow manure. Page 42 — Table of composition of gases in manure heaps and the effect of keeping manure heaps moist. Page 45— The percentage of water in unmanured and manured wheat and barley fields, together with considerable discu.ssion on the losses and retention of water in these fields. Also, the effect of manure in dry and wet seasons, oti the yield of crops for 51 years. Page 50 — A description of the process employed in manufacturing cotton- seed meal. Page 50 — Commercial classification of cotton-seed meal. Page 52 — A description of rape meal. Page 54 — Another method used in treating horns and hoofs. The produc- tion of fertilizers by packing houses. Page 56 — Analyses of nitrogenous guanos, with a list of the deposits that have been and are being worked, with comments on guanos. ^3.ge 57 — Composition of bat guanos. Page 57 — New process for recovery of ammonia from coal. Extent of manufacture of ammonium sulphate. P^ge 57 — How to detect adulteration. Table showing percentages of ammo- nia, pure ammonium sulphate, nitrogen and possible impurities in commercial sulphate of ammonia. Page 58 — Origin of deposits, amounted exported to date, value of, process of manufacture, and analyses of crystals. Page 58 — Effect of continued use of nitrate of soda. Page 59 — A full description of the process of manufacture, output and value, and comments on calcium nitrate. Page 59 — The process of manufacture, composition and comparative experi- ments with ammonium sulphate are given. 146 FERTILITY AND FERTILIZER HINTS Page 59— Table of composition of high grade nitrogenous products. Page 62 A full description of wool waste, shoddy, etc. Page 63 — A more complete discussion on garbage tankage. Page 64 — Vegetation and laboratory experiments with several high and low grade nitrogenous substances. Also a description and discussion of these materials. Page 67 — Statistics giving the amounts of nitrogenous materials used in manufacturing commercial fertilizers for 1900 and 1905. The total ammonia contained in manufactured fertilizers ; nitrogen removed by different farm crops. Page 68— Table showing the value of nitrogen in increasing yields for a period of 56 years, with a discussion of the same. Page 70 — Composition of raw bones. Page 71— Composition of good and poor steamed bone-meals. Page 71 — Composition of raw and steamed bones for comparison. Page 72 — Seven analyses of bone-black from sugar refineries. Page 72— Comparison of bone-ash, commercial bone-ash, pure ox bone-ash, horse shank bone-ash, ox bone-ash. Page 73 — A complete discussion of the phosphate deposits in the United States with statistics and tables on total production and individual production, market value, estimated life of, utilization, exports, devel- opment, Western deposits, and other interesting data. Page 74— Analyses of South Carolina phosphates. Page 74 — A description of how Florida phosphates are mined. Analyses of Florida phosphates. Page 75— Analyses of brown, blue and white rock. Page 75— Analyses of Canadian apatite. Page 76 — Composition of basic slag and comments on. Page 76 — List of phosphatic guano deposits, including those that have been and are being worked ; analyses of these guanos. Page 79— Influence of degree of fineness on value of phosphates, with experimental results. Page 83 — A complete description of the form of phosphoric acid in basic slag and its availability. Pao-e 83 — Amounts of acid to dissolve phosphates ; the reversion of phos- phoric acid. Page 85 —Classification of terms used for available and total phosphoric acid ; amount of available phosphoric acid contained in manufactured fertilizers. Page 87— Average composition of superphosphates and double superphos- phates. Page 88 —Amounts of phosphates used for manufacturing fertilizers. Phos- phoric acid removed by crops. Page 89— Experiments showing the fixation of phosphoric acid. Discus- sion on the absorption of phosphoric acid. notl;s 147 Page 89 — Experiments showine the effect of phosphoric acid. Page 89 -Crop returns frotn phosphatic fertilizers, with and without lime on several crops ; summary of these results. Page 90— A full description of the potash mines and the several salts deposited. Page 91 -Composition of kainit and a more complete description of it. Page 91 — Composition of sylvinit and a more complete description of it. Page 91— Composition of nmriate of potash and a more complete descrip- tion of it. Page 92 — Composition of potassium sulphate and a more complete descrip- tion of it. Page 92— Composition of double sulphate of potash and magnesia. Page 93 — Composition of potash manure salts. Page 93 -Composition of potash — magnesium carbonate. Page 93 -Table of composition of Stassfurt potash salts. Production of crude and manufactured salts, and consumption of the same. Page 93 —Analyses of leached and unleached ashes from several sources ; amounts of ingredients in different kinds of wood. Page 94 — Discussion and analyses of tobacco stems, stalks and wastes. Page 94 — Composition of cotton-seed hull ashes and a discussion of this product. Page 94 Full discussion of the manufacture of this product. Page 94 — Composition of beet molasses ash and fertilizer by-products made from it. Wine residue fertilizers. Statistics giving actual potash ma- terials and actual potash contained in manufactured fertilizers. Amounts of potash removed by different farm crops. Crop producing value of different potash salts. Page 97 —Experiments and discussion showing the effect of potash on dif- ferent kinds of crops. Page 99 — Comments on seaweed and its preservation. Analyses of differ- ent varieties. Comments and analyses of seaweed ash. Page 99 — Analyses of different kinds of marl and comments on the benefit of this material. Page 99 Several analyses of peat and muck. Liquid and flower fertilizers. Page 100 — Analj'ses of commercial pulverized sheep manures. Page 100 -A full discussion of these fish wastes and analy.ses of the same. Page 100 — Analyses of human excreta and sewage sludge, together with a complete discussion of sewage and sewage sludge. Page loi— Aiial3-ses and discussion on all the ashes. Page 10 1 —Leather scrap ashes, ivory dust and spent hops are di.scussed. Page loi — Analyses of soot. Page 102 — A more complete description. Page 102 —Experiments with silicate of potash and a di.scussion of its value and output. Page 102 — Analyses and discussion of salt. 148 FERTILITY AND FERTILIZER HINTS Page 103 — Full comment on sulphates of soda and magnesia. Page 104— Representation of the forms of lime, sources of carbonate of lime, and analyses of lime and limestone. Page 106— Experiments showing the effect of the form of lime on crop pro- duction, the fertility of the soil, and on soils rich in organic matter. Page 106— Amounts of lime removed by crops ; amount of lime in soils. Page 107— An extensive article on the acidity of upland soils, including observations on growing plants, effect of lime in conjunction with nitrate of soda and ammonium sulphate. Page 108— Analyses of gas lime. Page 108 — Analyses of gypsum ; effect of gypsum on clover ash and discus- sion. Page 109 — Fertility restored by some plants ; amount of nitrogen obtained from the air. Page 112 — Statistics given the cost of manufacture, cost of products, number of tons manufactured, consumption and distribution of fertilizer by states. Page 114 — Output of fertilizer factories, cost of nitrogen, of phosphoric acid, and of potash ; classification of commercial fertilizers. Page 116— Discussion of the requirements of fertilizer laws, comparison of the laws, model fertilizer law, comments on model law, tentative defi- nitions of fertilizers and of misbranding and adulteration. Page 117 — Converson factors. Page 118— A list of one maimfacturer's brands with simplified guarantees. Purity of raw materials as a basis of purchase. Page 125 — Commercial values of tankage and bone. Comments regarding valuations. Valuations show the cost of plant food. Objections to valuations. Points in favor of valuations. Valuations in other states. Chapter on high, medium and low grade fertilizers, including fillers, cost of different grades, the 100 per cent, of fertilizers and other inter- esting data. Page 128 — Amount of plant food purchased for I30 in factory and home mixed fertilizers. Selling prices and valuations. Analyses, cost, and valuations of home mixtures. Page 131 — A system of rebating when materials fail to reach the guarantee. Page 133— Home mixture formulas. How to determine the requirements of the soil. Page 135 — Number of brands sold in Georgia for several years. Page 136— Examples of different prices for grades of cotton-seed meal with comment. Page 137 — Fertilizer recipes or patent formulas with a discussion of the same. Page 137 — Table showing results on fertilizers kept in storage. Incompati- bles in fertilizer mixtures, showing materials that may and may not be mixed together. NOTES 149 Page 142— Chapter giving the requirements of crops classified into staple and special crops ; small grains ; forage crops ; market garden and truck crops ; fruits ; nuts. Fertilizer formulas for the several crops grown in the United States. Appendix includes a list of the Experiment Stations ; how to collect an exhibit of fertilizer materials ; fertilizer constituents in feed stuffs ; the number of pounds of a fertilizer required to furnish one pound of any element when the percentage of that element present in the fertilizer is known. INDEX Acid phospliale, 80; ccilor of, ii~ : manufacture of, 80. Acidity of soils, 104; how to lind out when soils are acid, 105. Acids and bases, y. Aerol)ic fermentation, 41. Agricuhural salt, 102. As^ricultural vakies of fertiUzers, i-'i. Alumimnn, 5. Ammonium chloride, 103. Ammonium nitrate, 102. Ammonium sulphate, composition and availability of, 57 ; manufacture of, 57- Anaerobic fermentation, 42. Apatite. Canadian. 75. Ashes, see wood ashes, coal ashes, etc. Ash in plants, 10, 11, 12. Azotin, 54. Bacteria, number in the soil. 22. luisic slag', 73 ; phosphate, 82. L5at guano, 56. ISedding- for litter, jf) : absorptive power of, 36; kind and amount used, 36. Beet molasses ash. 04. Beet refuse, 6r. Blood, dried, 52. Bone-ash, 72. Bone-black, 7r. Bone-dust, 71. Bone-meal, raw. 70 : steamed. 70. Bone phosphates. 77. Bone tankage. 7^. Bones, 70; mechanical composition of, 71. Brand and trade names of fertiliz- ers, 134- Brick kiln ashes, 10 r. Calciiun. 4: stilphale of, 81, 108. 1 1 Calcium cyanamid, 59; fertilizing val- ue of. 59; properties of, 59. Calcium nitrate, 59. Calculation of amouiUs from known percentages, 132. Calculation of percentages from known amounts, 131. Capillary water, 20; aiuounls of held by soils, 21 ; how to increase up- ward movement of. 21 ; how to prevent loss of. 21. Carbon. 3. Carbonate of lime, 104, Carbonate of potash, 94. Carbonic acid, 104. Castor pomace, 52. Chemical analyses, interpretation of, IT9; examples of, 119, 120, 121. Chemical elements, i Chemical symbols, i. Chlorine, 5. Coal ashes, 100. Commercial fertilizers, chapter on, 112; basis of purchase, 114; causes for large consumption, 112; fertilizing materials used by manufacturers, 114; how to lessen use of, 113: ton basis, 115; unit system, 114. Commercial values, 122: how to cal- culate. 124. Compost, 98. Corn cob ashes. 101. Cotton-seed, yield of product > from. 50. Cotton-seed hull ashe^. 94. Cotton-seed meal. 50: composition of. 50; value of, 50. Cow manure, ^y ; analysis of, 3(). I )cin'tril"!cation. 22. 1 )i\(Tsi("ication of crops, 2(). 152 INDEX Double sulphate of potash and mag- nesia, 92. Double superphosphate, 86. Drainage, 20; losses from, 26. Dry matter, composition of in plants, 8. Elements sometimes lacking in the soil^ 16; obtained from air and water, 16; present usually in sufficient amounts, 16. Erosion, 25 ; ways to check, 25. Essential elements, 16; replacing of, 17- Fallowing, 26. Farm manures, chapter on, 35 ; amount to apply, 46; analyses of, 39; bacteriological effect of, 46; benefits grass land, 45: care, preservation and use of. 40: composition of covered and un- covered, 44 ; composition of fresh and ro'tted, 43 : composting, 42 ; conditions affecting value of, 35; effect of fresh and exposed man- ure on crop production, 46; effect of kind and amount of bedding- used on value of. 36; effect of on mangolds with other ferti- lizers, 45; effect of leaching on, 40 ; effect of nature and amount of feed on, 39: fermentations in. 41 ; how to apply, 47 ; how to calculate amount produced, 39 ; improves the texture of soil, 45 ; influence of age of animal on value of, 35 ; influence of use of animal on value of, 35 ; keep manure moist, 42 ; kinds of manure, 35 ; lasting effect of, 40 ; physical effects of, 44; preserva- tives, 44 ; prevents mechanical loss by winds, 45 ; produces a better moisture condition, 45 ; store under cover, 43 : time to apply, 46; waste of, 40. Feather waste, 61. Fertilizers, chapter on, 112; a few remarks about, 134; agricultural values of, 121 ; amount to use, 142; brand and trade names of, 134; calculations on, 131, 132; commercial values of, 122 ; de- terioration of on storage, 137 ; elements required for crops, table of. 143 ; how applied, 139 ; how to purchase, 136; is it profit- able to use, 141 ; time to apply, 137; trade values of, 123: valua- tion of, chapter on, 119. Fertilizer laws, 115. Fertilizer materials, low grade, value of, 64; basis of purchase, 114: how to mix it at home, 130: how to purchase. 130; used by manu- facturers, 114. Filler, 128. Fish, dry ground, 54, 72. Fish scrap, fresh, 100. Formulas for crops, 143. Garbage tankage, 63. Gas lime, 107. Green manures, 108 ; classes of, 108 ; deep rooted plants valuable, in ; leguminous crops preferable for. 109; the best time to grow, no; the best time to plow under, 109. Guanos, how deposited, 55; nitrog- enous, 55 ; phosphatic, 76. Guarantee of fertilizers, 116, 117, 118; examples of, 116; fertilizers should reach their guarantees, 136; interpretation of, 116; mean- of, 116; study the guarantee, 136. Gypsum, 81, 108. Hair and fur waste, 61. Hen manure, 39; analysis of, 39. Hog manure, 38; analysis of, 39. INDEX 153 Jlome mixtures, chapter on, 126; calculations of percentages and amounts in fertilizers, 131, 132; defmitions, 126; does away with the purchase of unnecessary con- stituents, 128; manufacturers al- low credit. 127 ; manufacturers claims, 126; mechanical condi- tion of factory and home mixed fertilizers, 127; mixed fertiliz- ers compounded for the crop, 127; mixed fertilizers more easi- ly purchased, 127 ; plant food obtained at a lower price, 127 ; reasons for and against the use of, 126. Horn and hoof meal, steamed, 54; untreated, 61. Horse manure, 37 ; analysis of, 39. Humus, 13. Hydrochloric acid, i. Hydrogen, i. Hygroscopic moisture, 6. Inorganic matter, 13. Iron, 4. Iron sulphate, 102. Kainit, 91. King crab, 55. Leather meal : dissolved. 60 ; raw, 60; treated, 60. Leaves for bedding, 36. Lime, 104; amount to apply, 106; carbonate of, 104; decreases many fungus diseases, 107 ; form to use, 105: forms of, 104; how to find out when soils need lime, 104; how to apply, 105; mechani- cal action of, 107 ; phosphates of, 81. Lime-kiln ashes. 100. Linseed meal, old and new process. 51- Lobster shells, 100. Magnesium, 5 ; carbonate of, 103 ; sul- phate of. 102. Manganese, 5; salts of, 103. Manures, pulverized, 100 ; see farm manure. Marl, 99. Meat meal, 54. Miscellaneous fertilizer materials, chapter on, 98. Mora meal, 61. Muck, 99. Muriate of potash, 91. iMussels, 100. Xitrate of soda, 58 : composition and properties of. 58. Nitrification, 22. Nitrogen, 2; amounts for crops, ta- ble of, 143 ; excessive nitrogen in- vites disease, 68 ; for large crops and building up the soil, 66; for soils well supplied and long grow- ing crops, 66; forms of, 48; functions of, 67; how lost front the soil, 25, 26, 27 ; organisms that gather, 23 ; utilization of from air, 58. Nitrogenous materials, high grade, chapter on, 48 ; low grade, chap- ter on, 60 ; availability of, 63 ; field experiments with, 63 ; for immediate results, 65 ; kinds to use, 65 ; use of low grade in- creasing, 64; value of low grade, 64. Odorless phosphate, see basic slag. One crop farming, effect on fertili- ty. 28. Organic matter, 13. Organic nitrogen. 48, 49. Oxygen. 2. Peat. 99 ; for bedding, 36 ; absorption of. S7 ; dried. 63. Phosphates, chapter on, 70 ; availa- bility of, 78; available deposits of, 73 ; classification of, 77 ; how they occur, 70 ; influence of soil on availability of, 78; Florida 154 INDEX phosphates, 74 ; form to use, 78 ; kind to use, 89 ; mineral, "/Z ; or- ganic, 70; South Carolina phos- phates, "/Z ; Tennessee phosphates, 74- Phosphoric acid, 80; amount in soils, 88; available, 84; difference be- tween phosphates and superphos- phates, 83 ; difference of the forms of in superphosphates, 85 ; fixation of, 88 ; functions of, 89 ; insoluble, 81; loss of, 28; re- verted, 82; soluble, 81; value of reverted, 83. Phosphorus, 4; amount for crops, 143- Physiological water, 6. Plant food, amount available in soils, 15; amount remox-ed !)y crops, 14. Plants, acids and bases in, 9 ; amounts of water used by, 7 : ash of young and mature, 12; ash in, 10. 11, 12; composition of, 6; distribution of ash in, 12: dry matter of, 8; elements that make up, 10; food of, 6; how benefited by open soils, 19 ; how they feed, 5 ; must have room, 20; occurrence of mineral ele- ments in, 12 ; require oxygen, 20; salts in, 10: variation of ash in, 10; variation of water in, 7; water in young and mature, 8 : Potash, in soils, 94 ; chloride of, 91 ; effects maturity, 96; effects the leaves, 96; favors seed and straw formation, 96; fixation of, 95: forms of, 95 ; from organic sources, 93; functions of, 96: helps to neutralize plant acids, 97 ; loss of, 28 ; sometimes checks insect pests and plant diseases, 97; sulphate of, 91. Potash fertilizers, chapter on, 90. Potash-magnesia carbonate, 93. Potash manure salts, 92. Potash salts, 90. Potassium, 3 ; amounts for crops, 143. Potassium nitrate, 102. Powder waste, 102. Preservatives for farm manures, 44. Pulverized manures, 100. Quick-lime, 104. Rice hull ashes, loi. Rock phosphates, ~~. Rodunda phosphate, 75. Rotations, advantages of. 30; con- serves moisture, 34 ; furnishes a regular income, 2,2 : furnishes feed for live-stock, 2)i ', helps check insect and plant diseases, 31 ; helps distribute farm labor, 31; keeps down weeds, 30; leg- umes profitable in, 31 ; prevents losses of fertility, 2,7) '• regulates humus supply, 34 ; saves ferti- lizer expenditure, 34 ; utilization of deep and shallow rooted plants, },2> ' utilizes plant food more evenly, z;^. .Salt, common, 102. Salts in plants, 10. .Sawdust and shavings for bedding. 36 : absorptive power of sawdust, 37- .Scutch, 61. .Seaweed, 99. Sewage, 100. Sewage sludge, 100. .Sheep manure, 38 ; analysis of, 30. .Shoddies, etc., 62. Shrimp waste, 100. Silicate of potash, 102. .Silicon, 4. Slaked lime, 104. Sodium, 5; chloride of, 102: suipbalc of, 102. .Soil fertility, chapter on, 13 ; factors influencing, 13; loss by one crop IXDliX 155 laniiing, 28; Id.ss by system ul farming, 34; maintaining, chap- ter on, 25. Soil grains, surface area of, ly. vSoils, biological condition of, Ji ; cracking of, ly: inoculation of, 23; lumpy, ](j: mechanical com- position of, 18; plant food sup- ply of, 14; puddling of, 19; phy- sical condition of, 18; tempera- ture of, ]8; thawing and freez- ing of, 10. Soot, 101. vStraw as bedding, 3(1 ; abs(ir]iti\e power of, 37. Street sweepings, 10 1. Sulphate of potash, 91. Sulphur, 4. vSuIphuric acid, 80: manufacture of, 80. Superphosphates, chapter on, 80 ; fav- oritism for bone superphosphates, 86; how to make at home, 88: manufacture of. 80; names ap- plied to. 84 : no free acid in, 87 : the ditlerence between pliusphates and superphosphates, 83; the dif- ference of the forms of phos- phoric acid in, 81, 8j, 83. 85. vSylvinit. yi. 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