Class _il..j:^ Book ■^ Gopyiightj^i COPYRIGHT DEPOSm SOILS AND FERTILIZERS FOR PUBLIC SCHOOLS A Discussion Upon the Nature and Treatment of Soils and the Value of Fertilizers By CHAS. L. QUEAR Instructor in Charge of the Agriculture Department of the Muncie Normal. Two Years Acting Field Manager of the Guaranteed Seed Company, Piano, III. Two Years Field Adjuster, Farm Machinery Co. Co-Author, National System of Industrial Education. Edited by O. L. BOOR Graduate Ontario Veterinary College, Ontario, Canada. Acting Secretary of State Veterinary Examining Board. Practicing Veterinary Science, Muncie, Ind. Copyrighted 1915 by Chas. L.. Quear. FEB -5 1915 >Ci,A3ni600 TT^OR their invaluable assistance by way of help- ful suggestions and encouragement in the preparation of this book, the author desires to give special acknowledgment to M. G. Burton, editor- in-chief of the National System of Industrial Edu- cation, and to Julian R. Steward, dean of the Agricultural Department of the Muncie Normal Institute. UNDIRECTED PLAY DIRECTED PLAY INTRODUCTION. Scope and Purpose of a Text on Soils and Fertilizers for Beginners. In- structions to Teachers and Directions for Pursuing This Work. CHAPTER I. CONDITIONS NECESSARY FOR PLANT LIFE. Introduction — Conditions Necessary for Plant Growth — Work Required to Produce a Rain — Moisture and Warmth — What Happens to the Seed — Where the Little Plant Gets Food — Use of the Parts of the Plant — Air in Relation to Plant Life — Carbon — Relationship Between Plants and Animals — The Amount of a Plant That Comes from the Air — Water in the Air — Water in Relation to Plant Life — Water As a Food — Water As the Blood of the Plant — How Water Gets into the Plant — Plants Resemble Animals — Plant Foods — Elements and Compounds — Organic and Mineral Substances — Mechanical Support of Plants. EXPERIMENTS. 1. The Effect of Heat upon Plant Growth — 2. The Effect of Light upon Plant Growth — 3. The Effect of Moisture Upon Plant Growth — 4. To Show That There Is Air in the Soil — 5. Mineral Substance and Organic Substance. AGRICULTURAL APPARATUS AND HOW IT IS MADE. Window Box — Flower Pot Stand — Plant Label. QUESTIONS AND PROBLEMS. CHAPTER II. HOW SOILS ARE FORMED. What Soil Is — Mineral Matter — Organic Matter — Soil Moisture — Soil Air — Necessary Soil Conditions — How Soils Are Formed — Air As an Agent of Soil Formation — Chemical Action of Air — Oxidation — Temperature As an Agent of Soil Formation — Water As an Agent of Soil Formation — Plants As an Agent of Soil Formation — Animals As an Agent of Soil Formation — Culti- vation As an Agent of Soil Formation — Texture and Structure. EXPERIMENTS. 6. To Show That the Roots of a Plant Give Off Acid — 7. To Determine How a Soil Becomes Acid — 8. Rain Water and Soil Water — 9. To Show That Water Dissolves Mineral Matter from the Soil — 10. Oxidation. AGRICULTURAL APPARATUS AND HOW IT IS MADE. Percolation Rack — Flower Pot — Fire Kindlers — How to Make a Still Out of Cake Tins. QUESTIONS AND PROBLEMS. CHAPTER III. CLASSES OF SOILS. How Soils Are Classified— Clay— Clay a Cold Soil— Why Clay Is Called Heavy — Plant Food in a Clay Soil — Loam — Muck — Peat — Humus — Fertility and Humus — Nature of Humus — Supply of Humus — Conditions Favorable for the Formation of Humus — Relation of Mineral Substances to Decay — Value of Humus on a Soil — Sand — the Subsoil. EXPERIMENTS. 11. Diiference in Soils Demonstrated — 12. Physical Composition of Soils — 13. Temperature of Light and Dark Soils — 14. Why a Soil Becomes Cloddy. AGRICULTURAL APPARATUS AND HOW IT IS MADE. A Soil Screen — Home Made Scales — Scoops from Tin Cans — How to Sharpen Scissors. QUESTIONS AND PROBLEMS. CHAPTER IV. SOIL IMPROVEMENT. The Problem of the Farmer — Improvement of a Clay Soil — Soil Plowed Wet — Acid in a Clay Soil — Effect of Drainage on a Clay Soil — Effect of Humus on Clay — Improvement of a Loam Soil — Crops for Loam Soil — Im- provement of Muck Soils — Improvement of Sandy Soils — Humus on Sandy Soils- — Plowing at the Same Depth' — How Plants Live in Different Soils. EXPERIMENTS. 15. Planning a Rotation — 16. The Value of Organic Plant Food — 17. Water Holding Power of Soils — 18. Rapidity of Percolation in Different Soils — 19. The Effect of Organic Matter on the Tenacity of Soils. AGRICULTURAL APPARATUS AND HOW IT IS MADE. Soil Bins — A Rope or a Monkey Wrench Substituted for a Pipe Wrench — A Straight Edge. QUESTIONS AND PROBLEMS. CHAPTER V. SOIL MOISTURE. Free Water — Capillary Water — Where Capillarity Is Greatest — Method of Showing Capillary Action — Hygroscopic Water — Soil Mulches to Conserve Water — The Water Holding Capacity of Soils — The Conservation of Soil Moisture. EXPERIMENTS. 20. Effect of Soils on the Absorption of Substances from Solution — 21. Capillarity — 22. Distance Capillarity Will Lift Water — 23. The Three Kinds of Moisture in the Soil — 24. Water Consumed by a Plant. AGRICULTURAL APPARATUS AND HOW IT IS MADE. Dirt Band — Flat for Growing Plants — A Line Winder. QUESTIONS AND PROBLEMS. CHAPTER VI. DRAINAGE. A Plants Problem — A Wet Soil — The Value of Drainage — Drainage Gives Roots More Room — Drainage Increases Weathering Action — Drainage Raises the Soil Temperature — Indications That Drainage Is Needed — Drain- age Prevents Heaving — History of Drains — Hollow Tile for Underground Drains— Hov*^ Drainage Is Accomplished — Underground Drainage by Covered Drains — Drainage by Means of Open Ditches — Laying a Drain — Distance Apart and Size of Drains — Staking for a Drain — How Water and Air Get into a Drain — Soils That Should Have Drainage. EXPERIMENTS. 25. Effect of Lime on Turbid Water — 26. The Effect of Lime on Soils— 27. The Effect of Drainage upon Plant Growth — 28. Temperature of Drained and Undrained Soils, AGRICULTURAL APPARATUS AND HOW IT IS MADE. Specimen Case for Exhibit of Plant Foods — Mount for Small Samples. QUESTIONS AND PROBLEMS. CHAPTER VIL TILLAGE. Frontispiece; The Story of Tillage — Tillage — Purpose of Tillage — The Value of Securing Good Tilth — How Nature Maintains Fertility — Relation of Tilth to Root System — Continued Cultivation Injurious — To Restore Tilth — Effect of Moisture upon Plowing — Tools for Tillage — For Deep Tillage — For Shallow Tillage — The Plow — The Mouldboard Plow — Kinds of Mouldboards — The Disk Plow — Depth of Plowing — Fall Plowing — The Subsoil Plow — The Disk Harrow — Rollers — Use of the Roller — Cultivators — Garden Culti- vators. EXPERIMENTS. 29. Soil Mulches — 30. Rolling a Soil Increases Capillarity — 31. The Effect of Puddling a Soil — 32. Action of Frost on Soils — 38. The Plow. AGRICULTURAL APPARATUS AND HOW IT IS MADE. Corn Sheller — Tool Box. QUESTIONS AND PROBLEMS. CHAPTER VIII. ELEMENTS VALUABLE IN FERTILIZERS. Classes of Fertilizers — Value of Indirect Fertilizers — Nitrogen — How Plants Obtain Nitrogen — Nature of Bacteria — Partnership Between Plants — Life of Bacteria — Classes of Bacteria — How to Supply Bacteria — Legumes and Fertility — Legumes Do Not Always Obtain Nitrogen — Forms of Nitrogen — Phosphorus — How Phosphorus Is Removed from a Soil — How to Supply Phosphorus — Forms of Phosphorus — Raw Rock Phosphate — Acid Phosphate — Potash — Lime — Acids and Bases — How Lime Came into Use As a Fertilizer — Lime Stops the Waste of Phosphorus and Nitrogen — Add Limestone — Raw or Natural Lime — Burned Lime — Slaked Lime — Applying Lime — Cost of Lime- stone — Indications That Lime Is Needed. EXPERIMENTS. 34. Testing Soils for Nitrogen — 35. Testing Soil for Acidity. QUESTIONS AND PROBLEMS. CHAPTER IX. NATURAL AND ARTIFICIAL FERTILIZERS. When to Buy Fertilizers — How to Tell the Value of a Fertilizer — The Amount of Plant Food in a Comj)lete Fertilizer — Barnyard Manure — A Picture Story (eight pictures) — Spreading Manure — Waste of Manure — Storage of Manures — Green Manures — Ideal Crop for Green Manure — Rye As a Green Manure Crop — Vetch — Clovers As Green Manures — Cow Peas and Soy Beans As Green Manure Crops. EXPERIMENTS. 36. Testing Soils for Acid by Means of Ammonia — 37. The Effect of Different Kinds of Soil Mulches — 38. Plant Food Collection. AGRICULTURAL APPARATUS AND HOW IT IS MADE. Depth Planting Box^Alcohol Lamp from a Tin Box — Specimen Mount. QUESTIONS AND PROBLEMS. CHAPTER X. THE HOTBED AND WATER SUPPLY. Size of the Hotbed — Location of the Hotbed — Construction of the Pit — Construction of the Frame — The Sash — Filling the Bed — Soil to Be Placed Above the Manure — The Water Supply on the Farm — Health on the Farm — A Sanitary Problem for the Farmer — How Disease Is Carried — Bacteria As a Source of Contamination — Classes of Water — The Dug Well — Giving Animals Impure Water — Inspecting a Well — Testing Water for Organic Matter — Mud Holes on the Farm — Test for Chlorides — Test for Sulphates — Test for Lime Compounds. EXPERIMENTS. 39. The Weight of Soil Per Cu. Ft. — 40. Judging a Farm. AGRICULTURAL APPARATUS AND HOW TO MAKE IT. The Hotbed. QUESTIONS AND PROBLEMS. CHAPTER XL STUDIES IN CONCRETE. History of Cement — Ancient Cement — The Stability of Natural Cements — How Lime Is Made — Quicklime — The Newer Cement — Portland Cement — ■ Hydraulic Cement — Manufacture of Cement — Grinding the Raw Product — What Concrete Is — Importance of Concrete — What the Schools Can Do, EXPERIMENTS. 4L To Test for Carbonates — 42. Carbon Dioxide. AGRICULTURAL APPARATUS AND HOW IT IS MADE. Concrete Test Beam — Cement Match Safe. LIST OF ARTICLES NEEDED IN THE CONCRETE LABORATORY. SUGGESTIVE CONCRETE WORK, INDEX. vi INTRODUCTION. There has been much objection to the teaching of Agriculture in our District Schools, because teachers claim they do not have time to take up an additional subject, when they have so many subjects that are already required, and which must be taught. However, in recent years Agriculture has been coming into its own, and is being taught more and more in the schools. Teachers have begun to realize that any subject which holds the interest and attention of the pupils is worth while, and that any subject which does not hold their attention is not worthy of a place in our already crowded school course. In order to make Agriculture interesting to the pupil, we must base the work upon real practical problems which he can understand and appreciate. To do this is no small task, and it is a thing which demands a great deal of perseverance and initiative, on the part of teachers in such schools. The more ideas which an author attempts to incorporate into a text book, the more complex his text becomes, and the more difficult it is to follow. Therefore, in this text book we have taken only a few of the most important conditions and have tried to incorporate them in such a manner that they can be used by the average district or graded school. We have tried further to make the book correct — theoretically and practically. The entire text has been written for boys and girls of the country schools, with these two things in mind, and the success which attends its use presupposes a proper presentation of many minor details, which it would be impossible to include under this cover. Many teachers get the idea that the subject of Agriculture as taught in our public schools is a Vocational Subject. This is a mistaken idea, and the teachers should above all bear in mind that we are not making better farmers so much as we are making better men and women who are farmers. Naturally the teaching of Agriculture will make better farmers, and will serve to keep more of our boys on the farm. FOR THE TEACHER. The contents of the following pages give only a small portion of the great facts which can be brought to bear upon the sub- jects under discussion. Neither space, nor purpose permits more elaboration in this book, but the teacher in adjusting its con- tents to his immediate needs, can condense or elaborate the topics at will. The author has attempted to give the most vital facts and to present them in a logical order. It remains largely with the teacher, however, to demonstrate the value of the following pages, and this requires enthusiasm. This text presupposes that it will fall into the hands of willing people who have unbounded enthusiasm. If such persons use the following lessons as directed, supplementing them with their own judgment, much good will result. It is presumed that the interested teacher desires to do and know more than he is expected to teach, and for that reason we are furnishing a list of references which may be used for the personal benefit of the teacher, or class, or both. These refer- ences are valuable merely as an index to more elaborate stores of knowledge upon the subjects at hand. They are worth the time of both the teacher and student, if it is possible for either to study them. The experiments and questions at the end of each chapter should be worked by the teacher, before they are presented to the class. There are given pictures and specifications of many handy devices, which the pupils may make either at home or at school. This work will furnish a method of correlating actual hand work wdth the Agricultural Principles. If possible, pupils should be encouraged to make the things mentioned,- or, at least, some of them. Other handy devices may be designed by the pupils and teacher at their option. The work given in this phase of the subject is merely a beginning, and can be made as elaborate and extensive as the teacher desires. The devices given here do not demand expensive or uncommon material, or large shops, and as many teachers' difficulties as possible have been avoided in their designing. There will be difficulties peculiar to each community, which must be overcome, but it is hoped that the ingenuity of the teacher will prevail over all such inconveniences. A course would not be a success, unless difficulties were encountered. It will not be a success, unless these handicaps are, at least, partially mastered. One of the greatest aids to a successful course is a good note- book properly kept. Properly kept means written in a clear, legible hand, in ink, and at all times up to the last assigned lesson. Keep an accurate check on all note-books, and do not let students get behind in this phase of the work. Nothing destroys interest so quickly as getting behind. Have the pupils put the results of all experiments and observations in their note-books; also drawings of apparatus will help such a book. Link your drawing work with Agriculture and both subjects will be improved by the union. Do not make note-book work copy work. Copying a line here and there from a text book does not make a note- book. Have the note-books always ready for inspection, and inspection will seldom be necessary. One of the greatest aids in note-book work is a camera, if it can be had. The use of a camera in a course on soils registers accurately many conditions that can not be described in words. A few photographs placed in a note-book, showing the things under discussion, are an invaluable asset to every student. Know just where you are, and what you are going to do next, and your laboratory work will he the feature of the course. Do not ship the questions. They are the clinchers which hold the fabric together. Leave them out and your structure can not be well built, pedagogically or scientifically. Let your pupils be participants rather than spectators. If you make them feel that they have a part to play their respect for the work will never lag. To learn to know by doing is to see, to know, and to do. For a number of very valuable illustrations used in this text, the Editor is indebted to the following: Purdue Experiment Station, Lafayette, Indiana ; Independent Harvester Co., Piano, Illinois ; Cornell Experiment Station, Ithaca, New York ; Inter- national Harvester Co., Chicago, Illinois. CHAPTER I CONDITIONS NECESSARY FOR PLANT LIFE. Introduction: A little plant is a wonderful thing. It comes as you know, from a little seed which seems as dead as a grain of sand. It grows, produces flowers and fruit and becomes a thing of both beauty and value. Fairy stories are interesting, but they are less interesting and certainly not so true as the history of the most humble plant. In your story books your characters are able to run about and to do great and marvelous things, but in your Agricultural work, you will find while plants can not move about they can do many things that no man has ever yet been able to do. The Conditions Necessary for Plant Growth: Plants grow in practically every part of the world, from the torrid regions at the equator to the frigid zone of the arctic circle. The condi- tions, as far as climate is concerned, are very different. However, in a small degree, the same conditions exist at one place as at the other. All plants must have moisture, warmth, air, plant food and some sort of mechanical support. The plants at the equator you know have plenty of warmth. Strange as it may seem those at the arctic circle also have warmth, although not so much. The plants which grow in our own fields have a great deal of moisture; also the cactus which grows on the dry and barren desert has moisture, although we usually think of it as growing without this necessary element. It has adapted itself to such a degree that it needs only a little moisture, but moisture it must have, for that is one of the conditions necessary for life. 2 Soils and Fertilizers The leaves of most all plants are fortunately blessed with air, but the mechanical support of plants differs greatly. We usually give the mechanical support of plants small considera- tion, but at one time — as you will learn in a later paragraph — it was possibly the most important function the soil performed. We will take up each condition necessary for plant growth and discuss briefly its value. Work Required to Produce a Rain: We think very little of a rain or shower, as we watch it fall, but did you ever stop to think what a great task has been performed when even a little rain falls? The rain which falls on an acre of ground during a gentle shower weighs thousands and thousands of pounds. The farmer says he is very busy in the spring, getting ready to till his ground and plant his crops, but the water which Nature brings in one day is more than he could haul and put on his ground in one whole spring. In some places Nature does not bring the water for the crops, and put it on the soil in the form of rain. Men have to dig ditches and turn the water from streams into them to water the crops. This is called Irrigation, and costs the farmers thousands and thousands of dollars. So when we see the rain we must remember that by means of sun- shine and air Nature is doing a great and good work for the farmer by supplying the little plants with water. Moisture and Warmth: A little seed dropped into the soil without the knowledge of any human being — it was neither planted nor sown by mankind, but was distributed by one of Nature's agencies. There it lay in the soil all winter; it did not change, and appeared to be no different from the soil grains with which it mixed. You could not have found it, unless you had examined the soil very, very carefully, and you would even then have needed a microscope. But let us see what happens when Spring comes. Conditions Necessary for Plant Life 3 What Happens to the Seed: When Spring comes, this little seed, lying so quietly in the soil, becomes warm, and begins to take up the moisture. Both of these conditions — moisture and heat — come with the Spring. The seed requires heat before it will absorb moisture, and it requires moisture as soon as it becomes warm. As the seed becomes warm it drinks very greedily. The soil is so warm and comfortable in the Spring after a long and cold winter that the seed drinks very much, and since it can not stretch the seed covering, it bursts. This accident, how- ever, is not so very unfortunate, for although it destroys the seed it liberates the little plant which has been locked up, so it at once begins to grow. We see now that warmth and water have un- locked the door which kept the little plant imprisoned. Before the little plant can reach the sunshine, or can be seen by man, it must grow to a much larger plant than it is at this time. Of course, it can not grow without food, and being so small, it is unable to get food for itself. Where the Little Plant Gets Food: In searching for food this infant plant finds that the mother plant has filled its cradle home entirely full of the best food imaginable. The parent has furnished the food, so that all the plant has to do is to eat and grow. While it is growing and living on the food already fur- nished, it begins to send out little rootlets and a little stem with small leaves on it. The stem and leaves push upwards towards the sunlight while the roots seek to bury themselves deeper and deeper in the warm moist soil in search of water and food. It seems that a plant would not send its leaves toward the light and the roots into the ground if the seed were planted up side down. However, the plant, as we have said, is a wonderful thing, and no difference which way we turn the seed, the little plant will push its leaves and stem upward towards the light and the roots downward into the ground. This is shown in Fig. 1. r^ 4 Soils and Fertilizers Use of the Parts of a Plant: Not only does the little plant send each of its parts on its own special way, but it sends each to do certain things for the life of the plant. The little plant sends its leaves towards the sun to get light, heat and air, for air is usually present where there is plenty of light. It sends the little roots into the ground to get food and water, and to give the plant support, so that it can stand up strong and straight. The plant must have all of these con- ditions ■ — heat, light, water, air and me- chanical support — to grow and live, so it has good reason for developing roots and leaves while it is liv- ing on the food pro- vided by the mother. When this food is gone, it will have to live upon its own resources and to do this it will have to have the roots and leaves; the roots to gather food and water; and the leaves to gather air and to manufacture food, by the aid of sunlight. viy FIG. 1. The above shows that regardless of the position in which a plant is placed, its roots will grow down- ward and its stem and leaves upward. Air in Pelation to Plant Life: It seems strange that leaves are put forth to obtain food from the air, yet that is what they do. As a man could not live without lungs, so a plant could not live without leaves. The leaves breathe just as animals breathe, but thej^ do not use the same foods from the air that animals do. The Conditions Necessary for Plant Life leaves take carbon out of air in the form of carbon dioxide, and build it into their plant body. Carbon: Carbon in the air is a gas and is found united with oxygen. This carbon and oxygen gas, called carbon dioxide, is taken into the plant through the leaves. The leaves use the carbon and throw off the oxygen. The carbon is built into the plant and makes about one-half of the dry or woody portion of the plant. A good example of the carbon found in plants is coal. Coal is almost pure carbon which is left when plants die. When this coal is burned most of it, in the form of gas, passes into the air from whence it came. Although this seems impossible, with a little study you can see that carbon as gas goes into a plant and is formed into a solid, which can be burned as wood or coal when the plant dies and becomes dry. When burned the carbon in the plant goes back into the air as carbon dioxide gas, and is again ready to be used by a growing plant. Do not forget the fact, that through all of its changes, none of the carbon is really de- stroyed. From the time it enters the plant until it escapes there is no loss and no change except in its form. Any sub- stance may be chang- ed but no substance can ever be destroyed. Relationship Between Plants and Animals: Another valu- able thing that we should know is that while plant leaves absorb FIG. 2. The principal part of tiiis coal, the carbon, was taken from the air by the growing- plant, and will be re- turned to the air when the coal is burned. 6 uoils and Fertilisers carbon dioxide gas (carbon and oxygen mixed) and throw off oxygen, animals breathe oxygen and throw off carbon dioxide. Thus plants throw off a gas which animals use, while animals give off the proper gas for plants. Don't you think that Nature has been very wise in covering the earth with both plants and animals ? Did you ever regard plants as your friends, in the respect that they are working all of the time to furnish you not only substances to eat but air to breathe? Also the air carries the great amount of water which falls upon the soil and feeds the plants. Water always exists as a part of the atmosphere. Water may be seen passing into the atmosphere by noticing the spout of a tea-kettle while the water is boiling. The Amount of a Plant That Comes From the Air: When we sum up all the parts of a plant that come from the air, we find that about 97% of a plant has existed at some time as air. The picture below shows you how much this amount really is. The white corner shows what part of the plant comes from the soil particles. The large black portion of the square shows the amount that comes from the air. The air is a very complex and interesting substance, and contains many gases each of which plays its important part in the life processes of plants and animals. To fully understand the air and the part it ^jQ 3 plays in Agriculture, we would be ^"pSl^"^' ""' "''"""^' "'^"'' "'" compelled to study separately each of the gases, of which it is composed. It is like the large black locomotive; very interesting, but to be fully understood, so that we may appreciate it, each part must Conditions Necessary for Plant Life 7 be studied so that we may see what will happen when any one part is disturbed. Water in the Air: If we were to separate the atmosphere into its various parts we would find water vapor to be one of the principal compounds which is present. This water is obtained by the roots of the plants after it has fallen as rain. Of the sub- stances existing in the air only two are used directly by the plant. One is Carbon Dioxide, which is Carbon and Oxygen, and the other is Nitrogen. We will give special attention to these when we study Plant Foods. SOLIDS FIG. 4. The percentage of water in a tomato is larger than in milk. Water in Relation to Plant Life: Although the water which a plant uses comes from the soil, it is made up of two gases and was, therefore, a part of the atmosphere. These gases which make water are Hydrogen and Oxygen. They unite in the form of water, and are taken into the plant in this united form. Water as a Food: Plants use water as a food just the same as animals do. They build water into their cells until finally 8 Soils and Fertilizers the largest part of the plant is water; in fact, over seven-tenths of the average growing plant is water. Think of cutting a hundred pounds of hay to find that you had seventy or more pounds of water, the same as you get from the well. There is more water in a large ripe tomato than there is in an equal weight of milk, yet we drink the milk and eat the tomato. The solid material is in solution in the milk, while in the tomato it forms a network of peeling and fibre, which holds the mass in a solid form. The preceding picture shows you the percentage of water in a ripe tomato and in a can of milk. Water as the Blood of the Plant: Not only is water used as food for the plant, but it is the thing that carries all of the other foods to the plant. It performs the same tasks for the plants that our blood performs for us. Since plants can not eat solid food, the water must dissolve the food from the soil and take this food with it into the plant so that the plant can live. Since each drop of water will carry only a very little food, a great deal of water must pass through the plant to furnish all of the food that the plant needs. From three to five hundred pounds of water must pass through the plant to produce one pound of plant. This gives an idea what a large amount of water is re- quired to produce even an ordinary crop. Since a plant needs so much water, and since it does most of its growing during the warm summer months, when very little rain is falling, we can at once see that the problem of how to keep the water that falls as rain on the soil is as great as any problem in all Agriculture. How Water Gets Into the Plant: Since water is found in the air we sometimes think that it gets into the plants through the leaves, but this is not correct. All water must enter the plant through its little roots. If you will carefully sprout some kernels of corn, according to an experiment at the close of another chap- ter, you will be able to see the little roots called root hairs which absorb the water from the soil. These little root hairs are the Conditions Necessary for Plant Life 9 mouths of the plant and they are at work all of the time taking the water that is brought to them. Plants Resemble Animals: We find that a plant is very much like an animal in many respects. It has leaves for lungs and takes food out of the air by breathing just as animals do. A plant must have this air just as an animal must. A plant has water for blood and it serves this purpose for the plant just as well as the blood of an animal serves the animal. A plant has roots for a mouth, and they are busy all of the time getting the food for the whole plant. The plant can not run about as a boy can to hunt the food that he likes. It must take the food that is brought to it and do the best that it can. Now, if the food is not in the soil the water can not dissolve it and take it to the plant, therefore the plant will starve. In order that we may see to it that the proper foods are in the soil and where the plants can get them, we must know what plant foods are necessary. Plant Foods: Although the air is coiftposed of several sub- stances we have found that there are possibly only two of these substances that the plant can take directly into its body from the air. In a like manner, although there are many substances in the soil, there are only a very few that are necessary to the plant. At present there are ten plant food substances found in the soil, all of which are thought to be necessary for the growth of plants. Of these ten, only four are of great interest to us, for there is so much of each of the others in the soil, that there is no need for us to wonder about them. The four most important elements that are oft-times wanting in the soil are: Nitrogen, Phosphorus, Potash, and Lime. We will take up each one of these substances under the chapter on fertilizers, for. if one of these substances is absent in the soil, 10 Soils and Fertilizers plants cannot grow at all. It is by placing on the soil the plant foods that are deficient that we hope to increase our crops in the future. Elements and Compounds: We have referred to Nitrogen, Phosphorus, Potash, etc., as plant food elements, but before we can understand exactly what they are, we must know as definitely as we can what an element is. All substances are divided into two classes. They are either classed as elements or as compounds. When an object is com- posed of only one kind of substance it is said to be an element. There are only a few elements in existence, but they are combin- ed in a great number of ways to make compounds. Any object which is composed of more than one kind of substance is called a Fj^j 5 compound. For ex- A compound may always be divided into two or more amT)lp Watcr whilp apparently an ele- ment is in reality a compound. It is not an element because it is composed of two different substances. When we divide water into the two substances Hydrogen and Oxygen, of which it is composed, we cannot divide it further. Neither the Hydrogen nor the Oxygen will divide into other substances, so we call them elements. Compound Dements Thus the two simple elements Hydrogen and Oxygen when put together form a compound called water. The complete classification of elements and compounds is very diflBcult and Conditions Necessary for Plant Life H belongs to the study of Chemistry. We cannot discuss the sub- ject more fully in this chapter. See Fig. 5. Organic and Mineral Substances: It is rather difficult to get a clear understanding of the difference between organic and mineral substances, but a simple and yet sufficiently accurate way of expressing it is to say that all substances which contain car- bon are called organic substances, while all of those which do not contain carbon are called mineral substances. By a simple experi- ment we can easily divide a plant into these two classes. See Experiment No. 5. Mechanical Support: A long time ago the earth was covered with water, and plants were compelled to live entirely in water. . „ . FIG. 6. A, urganic and mineral substance; B, mineral substance alone, after burning- "A," which is a pile of straw. They floated around getting sunshine, moisture and air in abund- ance. We imagine that it was then very pleasant for plants, for they could move from place to place. Finally some plants drifted into shallow water and the bottom of the plants became covered with mud. At that time water held the plants up and the mud at the botton^ only kept them from drifting away. Gradually 12 Soils and Fertilizers however, the water left parts of the earth, and the plants that were growing there had to depend on the soil both to feed them and to hold them up. So now while the soil is a place where the plants can get food, it is probable that its first use was merely to hold or support the plants. Fig. 7 shows a plant that gets all of its food from the air. It is merely tied to the tree. FIG. 7. A plant that requires no soil. EXPERIMENT NO. 1. The Effect of Heat Upon Plant Growth. Obtain two flower pots, or two tin cans, and plant 5 or 6 large healthy seeds in each. Either corn or beans will be good seeds to plant. Be sure to "plant them all the same depth so that they will have an even chance to Conditions Necessary for Plant Life 13 grow. Place one pot of seeds in a warm place and the other in a very cool place. Water both alike^ and examine at the end of a week. What does this show you? Dig up the seeds that were in the cold soil. What has hap- pened to them.^ What happens when a farmer plants his corn before the ground is warm.^ Examine the seeds that were planted in the warm soil. What has become of them? What does this show you about the value of planting large seeds? Below you will find a picture showing how the seeds will be apt to appear. Make a drawing in your note book to show the results of your experiment. EXPERIMENT NO. 2. The Effect of Light Upon Plant Growth. If you have no flower pots for this ex- periment, bring two tin cans from home and with a nail, punch a few holes in the bottom of each. The cans may not look as nice, but they will work just as well as flower potSo You could also use small boxes, such rs chalk boxes, if you care to do so. Start some beans to growing in each of the two receptacles. After they are up nicely, that is, above ground three or four days, cover one pot with something that will keep out as much of the light as possible. You can easily shut out the light by putting a large can or light tight box over the plant. At the end of a week remove the covering and compare the plants. Explain what happens when a plant does not get suf- ficient light. Write the results of the experiment in your note book. FIG. 8. Seeds kept moist "Without enough heat on the left. Notice that they have de- cayed. The seeds on the right have pro- duced plants. The plants have' eaten the food, leaving only a seed covering. 14 Soils and Fertilizers EXPERIMENT NO. 3. The Effect of Moisture Upon Plant Growth. Plant some seeds in dry soil^ some in the same kind of soil kept moist, and some in the same kind kept very wet. Examine often and see what eifeet moisture has on the growth of plants. What effect does too much moisture have on the growth of plants.^ On a farm how may we get rid of any over supply of moisture.^ Write in your note book the results of this experiment. EXPERIMENT NO. 4. To Shorv That There Is Air in the Soil. You would be surprised to know how much air space there is in the soil a foot deep on an acre of ground. You can get an idea of the amount of space in a soil which is occupied by the air by taking a very little dry soil, and putting water in the place of air. To do this, take two glass vessels of the same size, such as beakers. Fill one beaker one-half full of clay soil, and jar slightly to settle it. Fill the other beaker to the same height with water. Pour the water from the beakei into the soil, and let stand until all of the soil is wet. Note the height to which the soil and water come in the beaker. The diiference between the height of the soil and water combined, and the sum of their heights, when separate, is the amount of air contained by the soil. For example: Suppose one beaker contained two inches of water, and the other two inches of soil, and when poured together, their combined height was three inches. Four inches the sum of the height of the water and soil minus three inches, their height when combined, leaves one inch, the amount of the soil occupied by air spaces. The amount of air spaces divided by the total amount of soil gives the percentage of the soil that is composed of air spaces. In this case, one divided by two equals fifty one-hundredths ; the per cent, of the soil which was air space. Write the results of this experiment in your note book. Repeat this experiment using different kinds of soils. Compare the air spaces in each. Write a discussion, telling what you have found out about air spaces in coarse and fine soils. Conditions Necessary for Plant Life 15 EXPERIMENT NO. 5. Mineral Substance and Organic Substance. Let us take a potato and wash it clean. Weigh it and then burn it in an oven until all that will burn has been removed. This will require a very high temperature to burn out all of the carbon. All that has been removed by the burning came from the air and is called organic substance. This includes the water, for it came originally from the air. Weigh that which remains. It is called plant ash; it came from the soil. It is also called mineral substance. Can you figure what part of the potato came from the soil? What part came from the air.f" o o a o o O 8 O O O O i 1 1 a' H 1 <| r| • 1 • l_ Fij.l, Window Box. to 0 Soils and Fertilisers Water which has soaked into the ground always contains more or less mineral matter. We know that plants must have mineral matter to live and thrive, so by growing plants in both kinds of water we can tell which contains the more mineral plant food. Take a dozen or more kernels of wheat and plant them. After they have grown an inch or so above the surface carefully dig them up. Take two small pieces of screen wire and carefully push the roots of five plants through each piece of wire. Put one piece of wire in each kind of water (one in clean pure rain water and the other in water which has come from a well), so that the water just covers the kernels and the roots. Keep the amount of water in the pans as near the same height as you can, and note the plants at the close of the week. What difference do you find.? If there is no apparent difference* and both samples are growing, leave alone until results appear. What did the soil water have which the rain water did not have.? Why do we call water the blood of the plant? See Fig. 13. A B FIG. 13. (A) Plants grown in soil water; (B) plants grown in rain water. EXPERIMENT NO. Oxidation. 10. Take two pieces of bright tin, or two pieces of iron and file them bright. (Any scrap of iron such as a piece of a hinge, an iron pipe, an old knife- blade or even a nail will do.) Coat one piece with vaseline or oil and leave the other just as it is. Expose the two alike to the outdoor air for a few days. Examine and note the changes. What is the change in the one piece called? What caused it? Why do people paint houses and machinery? O O Q'O-^- •] 1 F19. 1, Percolohon 1^q«U. 20 Wire Screen. r~i .J ■1 IJ Fig. 2, 5oil Screen- PLATE 4. 31 32 Soils and Fertilizers AGRICULTURAL APPARATUS AND HOW IT IS MADE. Percolation Rack. A rack for percolation bottles is a very desirable piece of apparatus to make. It is very useful in the study of soils and also presents some good Manual Training principles. A design is furnished in Fig. 14 which is very good, but the student can change his design to suit himself. Any kind of wood may be used for this rack, but it is better for the young student to use soft wood. One-half inch basswood is excellent. The finish may be of any nature; it may be painted, or stained and varnished, at the option of the student. Plate 4 gives dimensions and a complete design of a very serviceable percolation rack. FIG. 14. Percolation rack in use. Percolation Bottles. Lamp chimneys make excellent percolation tubes, but they are expensive and cannot always be had. Bottles may be used just as well, as they can usually be had for the asking. The large, long-necked round bottles of the beer bottle type are best. Before a bottle can be used as a percolation bottle it must have the bottom removed. The best way that this can be done is to tie a string which has been soaked in kerosene or turpentine around the bottle near the bottom and set it on fire. When the string has burned immerse the bottle suddenly in cold water. When tapped gently the bottom will usually break off smoothly. Now, plug the mouth of the bottle with cotton, or cover it with cheese-cloth and the bottle is ready for use. How Soils Are Formed 33 Flower Pot. In your experiments you oft-times have need for a flower pot. Tin cans with holes in the bottom may be substituted and will work just as well. How- ever, they do not present a very neat appearance as a rule. You can make a very nice flower pot out of paper which will be serviceable for some time. Take heavy building paper, or any heavy tough paper, and lay out the design for the flower pot as shown in Plate 3. Cut out your design and fold together. Cut all of the heavy lines, except E. F. Fasten the center pieces at the bottom, one over the other. Fasten the sides together and your flower pot is ready for use. If you will handle it carefully and not put too much water on the soil in it at any one time the pot will look nice for some time. Heavy waxed paper is the best to use if it can be obtained. Paraffined bristol board can usually be had at the book store or print shop and is very good for this piece of work. Fig. 15 shows such a flower pot before and after putting it together. FIG. 15. Fire Kindlers. It is very disagreeable to make a fire in a cold room when you have to depend upon shavings, bark and kerosene for kindling. A very excellent remedy for this is to make a bunch of kindlers that are always ready and which will start the fire. This may be done as follows: Take one quart of tar and three pounds of resin; melt them together, and before they are cool mix with as much sawdust as they will hold. Usually an old tin pail or cast away kettle can be used to do the melting. It is well 34< Soils and Fertilizers to add a little powdered charcoal to the sawdust. After you have worked in all of the sawdust that you can^ spread the mixture on a board to dry. When it is dry break into sinall pieces, and you will have enough kindling to last a long time. A match will light the kindlers and they will burn long enough to start almost any wood. Be careful in heating this mixture not to get it on fire. In case the material caught fire you would have difficulty in putting it out. How to MaJce a Still Out of Cake Tins. Rain water contains very little solid material, and can be used in experi- ments where pure water is required. Sometimes, however, pure rain water is not to be had and then we must prepare some water by distilling well water (that is, by boiling it, collecting COLff WATER |-}^g steam and changing it back into water by cooling it). The apparatus used to distill water is usually rather expensive, but the accompanying drawing shows an inexpensive method by which we may obtain comparative- ly pure water. This water still consists of two pans and a cake tin. The central cone of the cake tin must be cut down until its top is a little below the bottom of the upper pan. Water is placed in the top and bottom pan. When heated below, steam forms, passes up into the second pan and, striking the bottom of the top pan, is cooled and falls as water into the cake tin. The water in the upper pan will have to be changed frequently as it becomes hot. /JtJPURE vmT£8 FIG. 16. How Soils Are Formed 35 QUESTIONS AND PROBLEMS. 1. What is the boiling point of water, Fahrenheit? Centigrade? 2. How fast does a ray of sunshine travel? 3. What happens to water left in the sunshine? 4. If air presses down with a force of 15 lbs. to the square inch, what is the pressure per square foot? 5. Loam weighs 92 lbs. per cubic foot; sandy soil weighs 100 lbs. per cubic foot. How much would a cubic foot of sandy loam weigh if the two were mixed equally ? How much would a cubic foot weigh if they were mixed two parts sand to one part loam ? How much would a cubic foot weigh if they were mixed two parts loam to one part sand? 6. If ninety-seven one hundredths of a plant comes from the air, how many pounds of material in a bushel of corn comes from the soil? What is this substance called? 7. If a pound of soil water contains one-tenth ounce of phosphorus, one- tenth ounce of potash and two-tenths ounce of lime, how many ounces of pure water is there in a pound of soil water ? How much lime would there be in 14. lbs. of water? How much potash? 8. How many pounds of soil water like the above would have to pass through a plant to leave a pound of mineral matter? 9. How many pounds are there in a ton? 10. If three one-hundredths part of hay comes from the mineral matter of the soil, how many pounds of mineral matter must be furnished to the plant to produce one ton of hay? 11. If one cubic foot of soil contains four-tenths cubic foot of air space, how many pounds of water would it hold if water weighs 62,8 lbs. per cubic foot? 12. If a rock has one and one-half pounds of its surface broken into soil particles each year, how much soil would be formed from it in twelve years ? 13. If a cubic foot of water weighs nine-tenths as much as a cubic foot of loam, how much does a cubic foot of loam weigh? 14. What does qt. mean? pk. ? pkg. ? gal.? bu.? How many pks. in a bu. ? How many qts. in a bu. ? 15. How many hours in three and one- fourth days? 16. If the water in a ditch carries 100 lbs. of plant food an hour, how many pounds will it carry away in one and one-half days ? 36 Soils and Fertilizers 17. If flower pots cost 20c apiece for six-inch pots, 25c apiece for seven- inch pots, and 30c apiece for eight-inch pots, make an order for the following: One-half dozen six-inch, eight seven-inch, and one dozen eight-inch flower pots. Write out the order as if you were going to mail it to some firm. Show the total cost on the order. REFERENCES. Unproductive Black Soils ; State Experiment Station, Lafayette, Ind., Bul- letin 157. Halligan's Fundamentals of Agriculture; published by D. C. Heath Co. Experimental Botany, by Payne; published by the American Book Co. Encyclopedia of American Agriculture; by L. H. Bailey. Published by the American Book Co. CHAPTER III CLASSES OF SOILS. How Soils Are Classified: You veiy well know that the soil of one field is seldom Hke the soil of another field. Even in different parts of the same field, the soil is different. It would be hard to learn very much about soils if we had to study each field separateljr, so men have divided soils into different classes, and the soil of every field is described under these classes. Some people speak of all soils as being either heavy or light; others divide them into warm and cold soils. A very good method of classification and the one most com- monly used, is to divide soils into groups depending on the size of the soil particles, and the amount of humus which is present. When we classify soils on this basis, we have four types: clay, loam, muck and sand. Gravel is not ordinarily classified as a soil. If a soil contains clay and loam it is called a sandy loam., etc. So although we have four distinct types of soils, they are divided into several divisions, the following being the most com- mon: Clay, heavy clay loam, loam, sandy loam, light sandy loam, fine sand, medium sand, and coarse sand. Students should collect as many of these as possible. Clay: If the soil does not contain much organic matter, or humus, and is very finely divided it is called clay. The most important difference between clay and any other soil is the size of the soil particles. This difference produces many other con- ditions peculiar to a clay soil. Coarse soil allows water to pass through it readily, but fine soil as clay, holds a great deal of this 37 38 Soils and Fertilizers water. After a rain a fine soil stays wet for a long time, and this keeps out the air which makes such a soil undesirable for many crops. Clay a Cold Soil: Large amounts of water leave a soil of this kind by evaporating from the surface and as long as evapora- tion is taking place, the soil will remain cold. A good way to show that evaporation produces coolness is to moisten the finger a little and then wave it through the air. You will notice that the finger will become cool where the moisture has been applied, and will remain so until the moisture is all evaporated. / (1) Puddled Clay. FIG. 17. (2) Puddled Clay exposed to the action of freezing and thawing. JVhy Clay Is Called "^^ Heavy'': The finer the soil particles are in the soil, the stickier the soil is when moist, and, therefore, a clay soil is usually very sticky. This fact and the fact that it is usually very hard when dry makes it hard to work and farmers for this reason call it a "heavy" soil. Although clay weighs only 80 pounds per cubic foot and sand weighs 110 pounds per cubic foot, clay is called heavy soil and sand light soil, for clay is hard to work, while sand works very readily. Classes of Soils 39 In dividing soils into the classes warm and cold soils, we call clay a cold soil, for the reason that we have shown previously, and for the further reason that light colored soils do not absorb heat as well as dark soils. Organic matter gives soils their dark color and since clay contains very little organic matter, it is almost always light in color. The reddish or yellowish color which clay usually shows is due to the iron present. Plant Food in a Clay Soil: Although the above characteris- tic makes clay undesirable for a number of crops, there are many ways to improve it, and these methods will be mentioned under Improvement of Soils. One of the greatest advantages of a clay soil is the fact that the plant food is very readily soluble. The finer the soil particles the easier it is for water to dissolve the food, and for this reason clay soil is the richest of all soils in mineral plant foods. Grasses will grow on cold soils when other crops will not live, and since clay is a cold soil it is usually called grass land. Name some crops that will grow well in cool weather. Do such crops grow well on clay ground? Which is the better suited to clay ground, wheat or corn? Bring some clay from home and examine it carefully. Various experiments at the close of each chapter will help you to learn several important things about clay. Loam: As a general purpose soil, (for growing different kinds of crops ) a loam soil is the best soil that we have. Its texture is neither so fine as clay, nor so coarse as sand. Loam soil will hold a large amount of water and yet does not hold so much as to keep out the air. This soil is finely enough divided to sup- ply the average crop with mineral plant foods although the food is not so readily soluble as it is in the clay. Since a loam soil contains organic matter it is easy to work and does not become hard when dry, or sticky when wet. Also the organic matter makes the soil black, and a black soil absorbs heat better than a light soil, as has been mentioned. 40 Soils and Fertilizers For this reason a loam soil becomes warm early in the spring and is called a warm soil. That a white color will not absorb heat as well as black is shown by the fact that we wear white garments in the summer to turn off the heat from the sun. Loam is a good soil in which to plant garden vegetables since it is warmer than most soils. It is also a good soil for corn. Loam is very easy to till and is called a light soil although by weight it is as heavy as clay. Bring some loam from home to school and experiment with it as with the clay. Weight equal volumes of dry loam and clay. Compare their weights. Muck: A soil which contains large amounts of partially de- cayed organic matter is called a muck soil. Such a soil is usually found around old swamps where ponds have been and on low level ground. It is found in such places, because water is one of the chief agencies that helps to produce muck soils. To understand fully how such soils are formed we must un- derstand decay. When a plant dies it at once begins to decay and to go back into its former state. This decay is called oxidation, as mentioned previously. If in any manner air is kept away from the plant it will not decay and it is this principle that produces a muck soil. The plant when it dies is covered with water, or submerged in a wet soil and decay cannot continue with much rapidity on account of lack of air. Also heat makes decay take place more rapidly, and since a wet soil is a cold soil this helps to prevent the dead plant from decaying. After dead plants have accumulated on such a soil for a number of years we say that the soil is a muck soil. The dead plant is principally carbon and makes the soil black and sticky. A muck soil has a very undesirable structure and this must be changed before the soil can become very valuable. Also it is very cold on account of the moisture which it contains. This too must be remedied. A muck soil is most always unable to pro- Classes of Soils 4)1 duce a crop because it is acid. You should examine some muck soil veiy carefully for acid. A later paragraph will tell you how to do this. When organic matter, which is the main substance in a muck soil, is present only in small amounts and mixed with other min- eral matter, the soil is called a loam soil. If a large amount of organic matter is mixed with clay, the soil is called a clay loam, or gumbo soil. Gumbo soil is found in small sections of most states, as Iowa, Illinois, Indiana, etc., but in greater amounts in the Southern States, Alabama and Louisiana being good ex- amples. Peat: A large quantity of pure organic matter well decayed is spongy black and sticky. You can easily find some of this kind of soil if you will scrape some of the dead leaves from the soil in the woods. You will be apt to find a soil composed of dead trees, plants and leaves, and containing very little mineral matter. Such a muck soil is called peat. In cool countries, where it is always moist, the peat soils become very thick. In some of these countries, such as Ireland, the people dry this peat and use it for fuel. In other words, they complete the oxidation which is not completed by the air. Why is it that a rotten piece of wood if thoroughly dry will burn quicker than a solid piece of dry wood ? Get your teacher to explain to you how coal is formed. Humus: Humus is usually defined as decayed vegetable matter. This definition often causes humus to be confused with muck and peat. There is very little difference between the three terms, but they do not refer to the same things. Muck is un- decayed, or only slightly decayed organic matter, usually wet. It is found in low undrained areas. Peat is almost pure organic matter, and when dry can be used as fuel. Peat usually contains less inorganic, or mineral matter than muck. Humus exists as a portion of a peat, muck, or loam soil, and, indeed, is found in all soils that produce crops naturally. It will be discussed in the following paragraphs. 42 Soils and Fertilizers Fertility and Humus: Plant and animal matter partly de- cayed is termed hmnus, and its presence in a soil gives the dark color characteristic of highly productive land. The close relation between the color of a soil and its productivity is so general, that many farmers judge a soil entirely by the depth of the color. The most apparent change in the soil as it becomes exhausted is the gradual loss of color until the dark color has entirely disap- peared. At this state a soil is no longer capable of producing paying crops. In nine cases out of ten, the loss of soil fertility is in direct relation to the loss of humus, and in no case can a soil lacking in humus be naturally productive. The maintenance of humus, therefore, is the very foundation of increased soil productivity and good farm management. Nature of Humus: Any organic substance, when completely decayed, is changed into the gases and mineral substances from which it came. During the process of decay, we designate the substance as humus. The term humus is used as a general term. Humus proper is a very complex substance, partly soluble, dark in color and gummy or sticky in its nature. This gummy nature, together with the other properties, is well shown in a muck soil. Humus, while very complex, contains two classes of sub- stances. One class includes all substances which contain nitrogen, the most important factor in its composition, although possibly not the most important factor in its value. The other class of substances which goes to make humus is mineral elements. The mineral elements, however, are not so important or valuable as the nitrogenous substances. Supply of Humus: Most humus in a soil is supplied directly by the plants which grow on the fields. When the tops are re- moved from the plants in harvesting, only the roots go to furnish humus. In some cases, the entire plant is plowed under to in- crease this supply. Oft-times the plants are removed and later returned to the soil in the form of barnyard manure. Sometimes Classes of Soils 43 fertilizers derived directly from plants and animals are applied to the soil to supply hmnus, such as cottonseed meal, and dried blood. Also there are in the soil great numbers of microscopic plants called bacteria, which by their death and decay produce humus. Although the forms of life that may furnish humus are many, the one great fact remains, that our entire source of humus is the result of the death and decay of living things. It is the farmer's duty to see to it that humus which can only be obtained by the loss of life, is returned to the soil to the best possible ad- vantage. It should be remembered that if the humus content of a soil is retained, its fertility will last for a very long time. Conditio7is Favorable For the Formation of Humus: Since all humus is the product of decay, the rate at which decay can take place largely determines the humus present. Decay will take place only in the presence of air, heat and moisture. There- fore, if a soil is undrained, or is very compact, decay takes place very slowly, on account of the lack of air, and thus the produc- tion of humus is hindered. If, on the other hand, the soil is too well drained, as in a sandy soil, very much air passes through it and decay takes place too rapidly. In this case the organic matter is entirely destroyed, much of it going back to its original form of gases and mineral matter. Therefore, we may conclude that the drainage of a soil has much to do with the formation of humus. Also, a soil that is warm and well tilled, forms humus from vegetable matter very rapidly. Relation of Mineral Substances to Decay: A soil must have certain mineral substances present before humus will become abundant, for without these substances the organisms which pro- duce decay can not live. One of these substances, and, indeed, the most important one is lime. The subject of lime on the soil will be fully discussed in later paragraphs. Value of Humus On a Soil: As has been said, humus is 44 Soils and F ertilizers gelatinous or gummy in its nature, and very porous. When it is applied to a soil, it makes a better structure, and reduces the tendency of the soil to bake, or puddle. By making the soil crumbly in structure tillage is much easier accomplished, and in such a soil plants can root much more freely. Humus will absorb great quantities of water, and when present in a soil prevents the loss of large amounts of soil water. The water v/hich lumius absorbs dissolves from it large quanti- ties of readily available plant food which the plant can use di- rectly. The humus, besides furnishing plant food, helps also to liberate plant food from the mineral part of the soil. FIG. 18. (A) Plants in sand with humus added; (B) Plants in pure sand. Finally, humus in a soil permits plants to grow more vigor- ously and makes them better able to withstand disease or drought. It is usually considered that from one-third to one-fifth of the organic matter found in a soil is available (useable) in the form of humus. Sand: Pure sand would be a very poor soil for several rea- sons. It is so porous that it will not hold enough moisture to support a plant through the dry seasons. . It is so coarse and insoluble, that the water which a plant obtains from it contains Classes of Soils 45 very little mineral foods. It is not compact enough for plants to get a very firm foothold and consequently winds oft-times blow the plants over. On the other hand sand is a very warm soil, and when modi- fied with other substances a very early crop can be obtained, for plants will grow in such a soil in the spring before they will start to grow in other soils. Gardeners always like to have a sandy soil for the above reason. We can take a sandy soil, and if it is not too coarse, we can make a very excellent soil of it. We are to learn in the next chapter how to do this, as well as how to improve the other soils which have been discussed. Sand is the best soil we can use for germinating seeds. The sand is warm and admits air. It is also clean and can be handled without inconvenience. If you test any seeds for germination at this time use sand in the seed tester. It will not furnish food for the plants, but they will not need it so long as there is food in the seed from which they grow. The Subsoil: That part of a field which is called soil usually occupies the surface six to twelve inches. Sometimes, however, this surface soil is many feet thick and sometimes it is less than six inches in depth. There are several differences between subsoil and surface soil. The subsoil is usually harder to work than the surface soil and can generally be told from the surface soil by its color. The surface soil is darker in color on account of the organic matter which it contains. Also, the plant food in the surface soil is more readily dissolved than the plant food in the subsoil. As subsoils decay they become more and more like sur- face soils. The nature of the subsoil has much to do with the value of a surface soil. It determines in a large measure the fer- tility, drainage and texture of the surface soil. Dig down into a field at home. Notice the difference between the surface and the subsoil. About how deep is the surface soil? What kind of a subsoil do you find under the surface soil ? 46 Soils and Fertilizers EXPERIMENT NO. 11. Difference in Soils Demonstrated. Obtain three small jars or bottles which can be sealed tightly for col- lecting soil samples. Pint fruit jars are about as good as anything readily found. Go to the field and scrape away the plants and surface soil to about the depth of an inch. Take a sample of this soil and put it into one of the small jars. Seal it tightly so that none of the moisture can escape. Dig down 6 inches and take another sample of soil. Place this sample in another bottle and seal. Likewise secure another sample at a depth of 12 inches from the surface. When you return to the schoolroom weigh out equal amounts (about four ounces) of each soil. Spread each sample in a shallow pan and let it dry for two or three days. Weigh each sample again at the end of this time. The diiference between these weights and the first weight is the amount of water which each soil contained, that could be removed by evaporation. Note the color of each sample of soil. If you have a microscope, examine each soil with it. Heat each sample in an iron spoon until everything that will burn has been burned. Weigh each one again. The difference between these weights and the previous ones shows the amount of organic matter in each sample. The final weights show the amount of mineral matter which each soil con- tains. Write the results in your note-book in the following form: Depth of soil Total amount of soil Amount of moisture present Amount of organic matter present Amount of mineral matter present Color of the soil Size of the soil grains 1 inch 6 inches 12 inche<=! Averag-e Classes of Soils 4,7 EXPERIMENT NO. 12. Physical Composition of Soils. To say that a soil contains clay^ silt (a coarser form of clay) or humus does not mean anything very definite to a student. To let him find the clay, or silt, in a soil for himself is a different proposition. This experiment is arranged to permit a student to determine for himself the substances in a soil. To perform this experiment, obtain a glass tumbler, two quart fruit jars, or similar glass vessels, some soil of each kind to be tested, and a microscope, if there is one to be had. Put a tablespoonful of soil in a tumbler and fill full of water. Stir thoroughly. Let stand a moment and then pour oif the muddy water into one of the larger vessels. Put on more water, stir and pour off again. Repeat this operation four times in all, pouring the muddy water each time into the same vessel. Add water, stir, and pour off four more times, as above, except pour the water into the other large vessel. Eet the two vessels stand for a short time and compare sediments. That which remains in suspension is real clay and very fine silt. The sediment is loam and granulated particles of clay. The material which remains in the tumbler is principally sand. If you have a microscope examine the different soil grains and describe each. Proceed in this way with each of the soils to be tested. Heat a teaspoonful of soil in a large spoon until it is red hot. Which kind of soil burns? What do you have left.? What difference does the composition of a soil make as to the agricultural value of the soil.? Write a discussion explaining the results of this experiment. Estimate the percentage of each kind of soil constituent in the soils which you have examined. Name the soils that you have examined according to the substances which they contain. 48 Soils and Fertilizers EXPERIMENT NO. 13. Temperature of Light and Dark Soils. Take some loam soil and put about equal amounts in two pans. Place the bulb of a thermometer in each soil. Be sure that the bulb is covered with soil. Cover the surface of one pan of the soil with a thin layer of salt, sugar, flour or any similar white substance. Set the two pans in the sunshine and read the thermometers every ten minutes for an hour. Do not remove the ther- mometers to read them. What difference do you note in temperature.'* What does this show you about light colored soils? EXPERIMENT NO. 14. Why a Soil Becomes Cloddy. Take a small sample of all the kinds of soil which you can obtain and place each in a shallow pan. Cover them with water and stir until each is mixed thoroughly. Use equal amounts of soil and pour over each the same amount of water. Set the pans away to dry. Which kind of soil dries first? Why? Which last? Why? After they are all dry, examine them. Which one is the hardest? Which one is the softest? Why? What happens when we plow soil which is too wet? Do you think that it pays to start the plow a little early in order to gain a few days of time? ■ — »- * — -f- 1 J i 1 1 1 Y^£- -vJ^ ->t- r/Q / SO/L SCOOP r\ J"E i /^/$^^ ._«- Z^" ..!.. r/G3 NOA/£/>fy4D£ B/^LA/iC£:S nQ -^ PLATE 5. 49 50 Soils and Fertilizers AGRICULTURAL APPARATUS AND HOW IT IS MADE. A Soil Screen. There should always be a supply of soil kept in the laboratory, and this ean be prepared by use of a soil screen. A neat method of storing soil for school experiments is discussed in another chapter. In order to remove all large particles, clods, rocks, etc., from the soil it should be screened into the soil bins. To prepare a soil screen for this pur- pose obtain any soft wood of the dimensions given in Fig. 2, Plate 4. The fastening together of this frame for your soil screen can be accomplished by merely using 8d nails. If you cut your pieces for opposite sides exactly the same length your corners will be square. The bottom strips to hold the screen in place should be put on with one inch flat head bright screws. You can strengthen the soil screen if you desire by fastening three cornered blocks in each of the corners ; this can be done with glue and nails. This is not shown on the plate. Ordinary galvanized screen wire is a very serviceable form of wire to use and is fine enough for most soil work. Put dry soil into the sieve that you have made and, by shaking it over the soil bin, fine, clean soil will be obtained. Nothing adds interest to soil work so much as nice, fine soil with which to work. Home-Made Scales. Balances are very necessary in many experiments, but they are rather expensive. A pair of balances, which will do for all ordinary purposes, can be made at school. Take a 1-inch square upright and fasten it to a base, as shown in Figs. 3 and 4, Plate 5. Cut a V-shaped groove in the top of the upright. Obtain an umbrella rib and through the hole where the short stay was attached put a darning needle. Cut the umbrella stay so that it is the same distance from either end to the darning needle. Fasten pans to the arms of the balance as shown in the drawing. Lids from baking powder cans make good pans. Suspend the needle across the V-shaped groove in the upright and balance the pans by sticking gum or wax to the lighter pan. When the pans balance you have a very serviceable pair of scales which will weigh accurately enough for your use in the laboratory or schoolroom. Scoops from Tin Cans. In working with soils it is very convenient to have soil scoops. One which will serve very well can be made out of the material found around the home. Such a scoop can be used around the barn in the ground feed, salt, etc. If neatly fashioned, smaller scoops may be made to use in the sugar and flour bins, etc., of the kitchen. Classes of Soils 51 Take a tin can and either cut or melt off the top. 'Now, beginning at the open end and one-fourth way round each way from the seam, split the side of the can to within one-half inch of the bottom. You will need a heavy pair of shears to do this. Tinners' snips are best if you can obtain a pair. Then cut off one-half even with the splits which you have made in the sides. Round the corners of the open end and the body of your scoop is finished. See Plate 5, Fig. 2. Cut a piece of one-half inch wood to fit the bottom of the can. Place it as shown in the cut, Plate 5, Fig. 1. FIG. 19. Secure an old broom handle and cut a piece about three inches long for a handle. Put a screw through the board at the bottom of the can into the handle and your scoop is complete. You can make a hole through the tin for the screw with a nail if you have no metal drills. A one-inch or one and one- half-inch Number 8 screw is about the right size. When completed compare your scoop with the picture of the ones above. You might use any of the above styles you desire in making your scoop. How to Sharpen Scissors. It is very easy to sharpen a pair of scissors or shears even if you do not have a whetstone. If you use a pair of shears in making your soil scoop as above mentioned they will need sharpening. To sharpen them take a bottle or glass jar and put one blade inside the jar and the other outside. Act just as if you were trying to cut the jar. Repeat this cutting motion several times and your shears will be sharp. Do not use too much pressure. 52 Soils and Fertilizers QUESTIONS AND PROBLEMS. 1. If a sample of soil which weighed 6 oz. weighed 5 oz. after being ex- posed to the air for two days, what fractional part of the 6 oz. was water } 2. If a sample of soil which weighed 6 oz. weighed 2l^ oz. after being burned, what fractional part of the 6 oz. remained? 3. How many ounces in 12^ pounds.^ In one-eighth pound? In two and one-sixth pounds ? In three and one-fifth pounds ? 4. How many pounds and ounces in 28 oz.? In 56 oz.? In 80 oz. ? 5. How many square inches in a piece of screen wire 15 in. by 24 in.? How many square feet ? What would it be worth at 8c per square foot ? 6. Your experiments require 7 cu. ft. of clay weighing 80 lbs. per cubic foot; 9 cu. ft. of sandy loam weighing 98 lbs. per cubic foot, and 6 cu. ft. of clay loam weighing 92 lbs. per cubic foot, and 12 cu. ft. of humus weighing 50 lbs. per cubic foot. How many pounds would this be altogether? 7. A man has 12 A. of clay land worth $70 an acre; 22 A. of loam soil worth $120 per acre. What is the average price of his land per acre? 8. Loam yields 5% bu. more corn per acre than clay soil. How much more is the corn crop from a forty-acre loam field worth than the crop from a forty-acre clay field, if the corn is worth 40c a bushel and the loam soil yields 40 bu. per acre? 9. Forty-five gallons make a barrel. How many gallons in 603 bbls. ? 10. How much would a 45-gal. barrel of water weigh if 1 qt. of water weighs 2 lbs. and the barrel weighed 80 lbs.? 11. A cubic foot of clay soil will hold 32 lbs. of water. How many gallons, quarts and pints is this ? 12. Write an order to some one for the following: One-half bushel yellow corn at $5.00 per bu. One peck Red Clover seed at 8.00 per bu. Twelve packages Assorted Flower Seed at .10 per pkg. Three quarts Winter Onion sets at 1.20 per gal. How much money would you have to enclose for such an order? CHAPTER IV SOIL IMPROVEMENT. The Problem of the Farmer: Most farmers know quite well how to feed animals, and when to market them, how to manage a farm, and what kind of farming they are best prepared to do. But the number of farmers who are acquainted with their soils, and who know how to improve them are very few indeed. The problem of soil fertility is the greatest problem confronting the farmer today. This includes the problem of soil moisture, for soil moisture composes the greatest portion of all crops. Every student must realize that each field is a separate prob- lem, and its case must be considered individually. No two fields respond exactly alike to the same treatment, for they are never lacking in exactly the same substances in the same amounts. No general rules can be used to cure a soil any more than a few general facts will cure all sick people. The person who attempts to cure or benefit the productive power of a soil must know how to find out what the soil needs, how best to apply this needed material, and when and what to apply. A doctor of medicine examines a sick person and after find- ing out what is wrong proceeds to correct that ailment. He does not give every sick person the same kind of medicine. Neither should you give every soil the same treatment. You as a soil doc- tor, should do more than the doctor of medicine. You should not only be interested in making poor sick soils well, but in making good healthy soils better. It is a very difficult study, and the problems are large ones. There are a few rules for im- 53 54 Soils and Fertilizers proving the various classes of soils that we should knovs^ and be able to apply, just as there are a few rules for maintaining good health. The special needs of soils we will have to learn by ob- servation, practice and study. Improvement of a Clay Soil: One of the things that causes a great deal of trouble for the farmer is the fact that a clay soil puddles very easily. Soil particles arranging themselves very B Fig. 20 A (A) Treated soil; (B) Part of same field untreated. close together so that they become very hard in structure when dry is called puddling. (See Fig. 17.) Puddling is caused in most cases by plowing or cultivating the soil while it is too wet. Farmers say of such a soil that it bakes. Puddled soil may always be seen in the bottom of a hog wallow after the water has evapo- rated. The soil while wet has been stirred by the hogs, and the soil grains have been able to get as close together as possible. Soil Improvement 55 When such a soil dries, it becomes almost as hard as cement. In- deed, a long time ago people used to make brick this same way. They would stir a clay soil while it was very wet and then make it into the shape of bricks. They would leave these bricks to dry in the sun and after they were dry, they called them sun dried bricks. You might try making a brick like the people a long time ago used. Get your teacher to tell you how bricks are made today. If there is a brickyard near your school go see how bricks are made. Soil Plowed Wet: When soil is plowed too wet it behaves just as if it had been made into sun dried bricks. Plants will starve in such a soil, for all of the plant food is locked up. A clay soil plowed too wet will not recover from the injury it re- ceives for two or three years. Therefore, one of the most im- portant rules to follow regarding clay is dont plow while the soil is too wet. Soil is too wet to plow when a handful of it worked in the hand and made into a ball will pack and become slick on the outside. Acid In a Clay Soil: Another thing that sometimes causes a clay soil to puddle is the acid which it contains. Acid in a soil tends to cement the soil grains together, making a very hard compact mass. It should therefore be removed. This is best done by removing surplus water and by the addition of soil amendments. By soil amendments we mean anything which will help to correct an improper condition of the soil. This sub- ject will be discussed under the chapter on Fertilizers. The only way to remove surplus water successfully is by drainage, so remember that clay should always he well drained. Effect of Drainage On Clay Soil: In a clay soil the texture is too fine to permit air to penetrate, or to permit water to pass through as it should. We cannot change its texture much, but we can change its structure. Plowing while the soil is wet should 56 Soils and Fertilizers change its structure, but this method would ruin the soil. It would make the clay soil very lumpy and hard. The drainage of a clay soil allows air to penetrate more freely and air acting on the lime which is present sticks little groups of the soil grains together, which makes the clay coarser in structure. These little groups of soil grains are not stuck together so tightly as to make them worthless. This permits the air and moisture to pass freely and is a very beneficial change in the soil structure. It is in fact the main reason why we should drain a clay soil. On some soils drainage does not have this eiFect, because there is no lime in the soil. Such a soil needs lime applied to change its structure. Effect of Humus On Clay: Humus applied to a clay soil is one of the best methods of modifying its structure. Humus makes the soil more porous and allows air to enter freely. It not only admits the air, but also helps to prevent the soil from washing by rain, or drifting by wind. A clay soil containing humus is not ordinarily easy to puddle. It does not become hard when dry. Clay soil alone contains mineral plant foods in abundance, but since plants can not live on mineral matter alone, we must apply humus so the plant may have all of the food material that it needs. Remember that a clay soil needs humus more than any other soil both as food for the plant, and as an agent to modify the structure of the soil. Commercial fertilizers are usually of little value to clay soil. This will be discussed further under the chapter on Fertilizers. Improvement of a Loam Soil: The structure of a loam soil is usually very good. It contains both organic and mineral plant foods. It is classed as a warm soil. If, as sometimes happens, a loam soil is cold, it is because the soil needs drainage. This is one thing that loam soils need in many cases. Soil Improvement 67 While both mineral and organic plant foods are present in a loam soil, some of the essential ones may not be present in large amounts. The ones which we need apply as fertilizers must be largely determined by the crop that is to be grown on such a soil, as well as the manner in which the soil has been cropped for the past several years. Crops For Loam Soil: Rapid growing crops, as corn, are usually grown on loam soils. Such crops require large amounts of moisture in a short growing season. Therefore, the moisture supply of a loam soil must be looked after by proper drainage and tillage. A loam soil usually becomes poor rapidly, because it is most likely to be abused. Air can pass through it readily, and as a result the organic matter oxidizes rapidly. If we con- tinue to raise large crops on such a soil, and take away the crops in a few years the supply of organic matter is almost gone, and as a result the structure, tilth and fertility is destroyed. A loam soil is a good soil, but it requires care or it will not remain fertile and productive. Improvement of Muck Soils: Muck soils are quite variable and no rules for improving such soils will apply generally. Some muck soils contain more organic matter than others and again this organic matter is more completely decayed in some cases than in others. However, the one condition common to all muck soils is the large amount of organic matter which is present. This condition is favorable for a very fertile soil. Organic matter in large quantities makes a soil that does not drain naturally, and further such a soil is almost invariably acid. Artificial drain- age is one method of improving such a soil, and the addition of fertilizers, or substances to correct the acidity of the soil is an- other. It is not hard to correct the acidity of soil if you know how to go about it. Some people try to improve muck or humus soils by burning the top layer of soil. This is a poor way of improvement and 68 Soils and Fertilizers should not be practiced except in very rare cases. When this is done but very Httle acid is neutralized, while a great deal of or- ganic matter is destroyed. Drainage and soil amendments are the secret of success in handling muck soils. Improvement of Sandy Soils: A sandy soil may be made a very excellent soil by proper treatment. A sandy soil is loose and open in structure, which condition permits the roots of a grow- ing plant to pass freely in all directions. In such a soil the re- sistance offered to the roots is not sufficient to check their lateral growth, and the water is usually far enough below the surface to permit a plant to root deeply. Plants must have their roots scattered over a large area to obtain the moisture which they re- quire, particularly through the summer months. When you stop to think that a corn plant on a warm day in July or August will consume as much as two and one-half lbs. of water and that the soil from which this must be obtained is so dry that by no pos- sible means could we squeeze a single drop from it, you will see why it is necessary that the roots cover a larger area. Humus On Sandy Soils: If we add humus to a sandy soil we increase the power of the soil to hold water, for humus is like a sponge. It soaks up large amounts of soil water, yet it does not prevent the roots from growing freely in all directions. If we drain a sandy soil and put the drains rather close to the surface, the water can supply the plants for a longer period of time. By putting a shallow drain in sandy soil, we raise the level of the soil moisture which permits the plants to use water which they would not otherwise obtain. This will be discussed further under drainage. Plowing At the Same Depth: By plowing at the same depth each year we may improve the water holding power of a sandy soil. Plowing at the same depth year after year has a tendency to firm the soil below the plow, and this allows the moisture to be brought up from below more readily. Soil Improvement 69 Sandy soil has a great advantage over clay soil in the respect that it neither bakes when it becomes dry, nor becomes saturated with water after every rain. Also a plant can obtain what moisture there is present from a sandy soil easier than it can from a clay soil, for a sandy soil yields its water readily while a clay soil retains it vigorously. A sandy soil is from 5 degrees to 10 degrees warmer in the spring than a clay soil and will warm up to a greater depth early in the season. The warm spring rains soak into a sandy soil and warm it by forcing out the cold water that is already present. In a clay soil the cold water that is present remains and the spring rains run off as surface water. This fact makes a sandy soil an earlier soil for planting crops. However, the water that passes through a sandy soil takes plant foods with it and these must be replaced by the addition of fertilizers. Humus will replace some of these plant foods. How Plants Live In Different Soils: Plants adapt them- selves to all kinds of soils, and this fact lias helped many plants to become used to certain kinds of soils, and has permitted them to thrive there although they formerly preferred another kind of soil. We associate certain crops with certain soils and it is always best to plant the desired crop on the soil suitable for that crop, rather than to modify the soil to suit the crop. It is per- fectly correct to study methods of modifying the soil, but we must not disregard the nature of the plants we are raising. The crops which we are attempting to raise, by careful selec- tion can be so chosen, as to fit the particular kind of soil which we are tilling. By this means we can avoid needless expense in a vain effort to change the nature of the soil. As a rule, fit the crop to your soil, rather than your soil to the crop. 60 Soils and Fertilizers EXPERIMENT NO. 15. Planning a Rotation. Have each pupil bring samples of surface soil and of subsoil from the fields at home. Classify each and compare the value of the diiferent sub- soils. These soil samples can be brought to school in small tin cans or boxes. Have pupils make drawings of the farm at home^ showing each field. Write in the drawing of each field the kind of crop grown, the kind of sur- face soil, and the kind of subsoil. On this farm plan a four years' rotation. Write the name of the crop to be planted in each field, and the time the same should be planted. Note how many times each field must be plowed in four years. Note how many months each field will lie idle during this time. Upon which fields would you place the barnyard manure in your rotation.'' Why.? By using colored crayons and letting different colors denote different crops a very interesting map may be made. EXPERIMENT NO. 16. The Value of Organic Plant Food. Clean sand contains all of the mineral plant foods, but does not contain organic matter. We will test the plant-producing value of organic matter by growing some plants in pure sand and some others in sand to which organic matter has been added. Obtain two flower pots which are near the same size. Fill one with clean sand, which you have burned at a high temperature for an hour or more. Fill the other about one-half full of the same kind of sand. Fill it the remainder of the way with organic matter. Mix the two kinds of soil in this pot thor- oughly. The organic matter which you add should be well rotted manure or decayed leaves, from the woods. Use whichever is the more convenient. Plant five or six seeds of some common plant, as corn, in each and subject both to the same conditions. Water as often as necessary with clean rain water and observe the results at the end of each week for four weeks. Write in your note-book the results which this experiment shows. At the close of the experi- ment write a brief paragraph telling the value of barnyard manure. Soil Improvement 61 EXPERIMENT NO. 17. Water-Holding Porver of Soils. Let us compare the water-holding power of the four main types of soils in the following manner: Take four percolation bottles which will hold a quart each and stuff cotton in the necks of them, or, if it is more convenient, tie cheese-cloth around each. See Fig. 14. Fill each bottle one-half full of soil as follows. Into one put sand; into another clay; into another loam, and into the last humus. Jar each bottle slightly to settle the soil. Now place the bottles in the percolation rack and into each bottle pour one pint of water. Observe the amount of water which passes from the soil as free water. Which soil retains the most water ? Which one the least? Can you explain the results of your experiment and its value .^ Make a drawing of the apparatus. EXPERIMENT NO. 18. Rapidity of Percolation in Different Soils. The purpose of this experiment is to demonstrate the rapidity with which water escapes through the different types of soils. Obtain four bottles with the bottoms removed and tie a piece of cheese- cloth over the mouth of each. Fill each bottle two-thirds full of soil, using a different soil for each bottle. Place the bottles in a percolation rack, mouths downward. Pour water on each soil, a little at a time, until it begins to drip from the mouth of each bottle. After water is dripping from all of the bottles, note the amount of water which drips through in a given time, say four periods of five minutes each. Keep a supply of water above the soil in the bottles all of the time. Which soil loses the most water? Which one the least ? Ask yourself five questions about this exercise and write the answers. Show them to your teacher. Make a sketch of the apparatus and put it in your note-book. EXPERIMENT NO. 19. The Effect of Organic Matter on the Tenacity of Soils. Take two small pans and put some clay in each. Pour equal amounts of water over the clay in both pans and stir until you have a stiff batter in 62 Soils and Fertilizers each pan. Into one pan put a small amount of very fine and well rotted humuS;, and stir until it is thoroughly mixed with the clay. Set the pans away for the soil to dry. When thoroughly dry break or crush the soil in each pan. Note the hardness of each soil. What effect does humus seem to have on clay.f* Write one sentence on the Value of Humus to Clay. REFERENCES. Call and Schaf er's Laboratory Manual ; published by the MacMillan Co. First Principles of Agriculture; by Goif and Mayne. Published by the American Book Co. Utilization of Muck Land; Regular Bulletin 273 State Agricultural Col- lege^ Lansings Michigan. Use of Fertilizers on Indiana Soils; Cir. 10, State Experiment Station, Lafayette, Ind. Mayne and Hatch, High School Agriculture; published by the American Book Co. Nolan's 100 Lessons in Agriculture; published by Row Peterson and Co. Plant Food in Relation to Soil Fertility; State Experiment Station, Ur- bana, Illinois, Cir. 157. Soil Fertility in Iowa; Bulletin 150, State Experiment Station, Ames, Iowa. Soil Improvement 63 AGRICULTURAL APPARATUS AND HOW IT IS MADE. Soil Bins. It is very unhandy to keep soils in the schoolroom unless you have some- thing especially made for holding them. When soils are kept in the school- room they are often placed in boxes of all sizes and shapes which makes the room look untidy. Also this takes up a great amount of unnecessary space. It is much more desirable to have a row of soil bins. Take four boxes which are the same size and bolt them together. Be sure that they are good, tight boxes, so that when they are filled, soil will not constantly leak from them. Put legs on the boxes to hold them the desired height. It is well to bolt the legs to the boxes, for they will have to support considerable weight. Put a lid on the boxes, as shown in Fig. 2L Then paint the whole thing some desirable color. Using a different colored paint from that which you used on the boxes, paint on the front of each box the name of the soil which you expect to place in it. This will make a very attractive and useful soil box, and will prevent a lot of untidiness otherwise unavoidable. A box like the above, having only one section, makes a very good waste box. FIG. 21. Soil bin. A Rope or a Monhey Wrench Substituted for a Pipe Wrench. Oft-times the farmer has to uncouple a pipe and, without a pipe wrench, this presents a serious problem. However, this task can usually be accom- plished by the aid of a piece of rope and a short stick for a lever. Wrap the rope around the pipe, as shown in the illustration. Fig. 22, and it will not slip, 64 Soils and Fertilizers V but will grip the pipe very tightly. Now insert a stick as shown and unscrew the pipe. A monkey wrench may be used for a pipe wrench by inserting a bolt under the upper jaw of the wrench. The method of doing this is shown in Fig. 22-B. A Straight Edge. A straight edge is a very desirable thing to have around a shop^ and one can be made very easily. Select a clear piece of pine (five or six feet long) and plane one edge as straight as possible, testing it with the eye. In order to test it more accurately, lay it upon a smooth surface and mark with a pencil against the edge which you have planed. Then turn it over and with the same edge on the line which you have already made, mark again. These two lines show every defect in the straight edge, just twice as bad \M ^^H .^fllH ^^ ^^ really is. In this manner ^kHH ^Jh^HP^ defects can easily be found. ^H^l ^5[^HWMM|||fc|g^ Work the high places down with ^^^1 ^^^j^^^^^^J a sharp plane and test occa- sionally as explained above. In this manner make the edge per- fectly straight. Such a straight edge will be valuable in marking boards to be ripped, or in testing work for straightness in the shop. FIG. (A) Rope for pipe wrench; wrench for pipe wrench. (B) Monkey Soil Improvement 65 QUESTIONS AND PROBLEMS. 1. If draining a field increased the corn crop by 12 bu., worth 40c per bushel, how much would the increased yield on a forty-acre field be worth? On how much money would this amount pay interest at 6 per cent ? 2. A person bought 20 acres of land which was planted in corn. He paid $150 an acre for the land and corn. How much did the land alone cost him if the corn yielded 60 bu. per acre and he sold it for 40c per bu. .^ 3. A soil weighing 80 lbs. per cubic foot absorbs five-eighths of its weight of water. How much water does it hold? 4. A soil weighing 92 lbs. per cubic foot is five-eighths water. How much dry soil is there in a cubic foot? 5. If 275 lbs. of moisture are required to produce 1 lb. of a corn plant, how much will one hill of corn require if it weighs 7^4 lbs. ? 6. There are 43,560 sq. ft. in an acre. If we place one ton of manure on an acre, how much is that per square foot? 7. One cubic foot of soil admits % cu. ft. of air. How many cubic feet of soil are required to contain 1 cu. ft. of air? 8. What makes a soil hard if it is plowed too wet? 9. Explain puddling of a soil. 10. Why can not plants grow well in a cloddy soil? 11. Under what condition is a soil too wet to plow? 12. What is the value of drainage to clay soil? 13. What is the value of humus to clay soil? 14. What is the use of air in the soil? 15. Why does a loam soil need care? 16. Why is burning a humus soil a bad method of improvement? 17. What is the advantage of giving plants plenty of room for their roots? 18. How may we increase the water-holding power of a sandy soil? 19. What is meant by surplus water ? CHAPTER V SOIL MOISTURE. Plants take water from the soil through their roots. This water passes directly to the leaves, and that which is not required by the plant is evaporated from the leaves into the air. One ton of dry corn crop will use during its growing period about three hundred tons of water. This water is obtained by the plant in three conditions: (1) as free water; (2) as capillary water; (3) as hygroscopic water. Free Water: Free water is that water which flows along beneath the surface of the soil, and is not retained by the soil grains. The passage of this moisture, due to its weight down through the soil is called percolation. (See A Fig. 23.) The water which flows from a tile ditch, or into a post hole is free water. It is oft-times called underground water. The free water in some soils is very close to the surface, while in others it is very deep. Plants can not send their roots below the level at which the free water is found, and this place in soils is called the water table. (SeeB Fig. 23.) If the water table or level of the free water is very near the surface, the plant has very little soil from which to get its food and cannot grow well. We drain soils, therefore, to lower the level of the free water. This gives the roots of the plants more soil from which to obtain food. We do not want the level of the free water to be too deep, for if it is too far down to the free water, the capillary water can not supply the surface soil as it should. 66 Soil Moisture 67 Capillary water depends upon the free water in the subsoil for its source of supply. The depth at which the free water or water table should be located in well managed soils depends upon the nature of the subsoil ; six feet being a maximum depth. Capillary Water: The water which creeps from soil grain to soil grain through the soil is called capillary water. The power by which this water is lifted from soil grain to soil grain is called capillary action, or capillarity. In capillary action the water moves just as the oil moves in a lamp wick. (C Fig. 23 shows capillary action.) You have no doubt observed this thing many times in the lamp. The oil which goes up through the wick corresponds to the cap- illary water in the soil, while the oil in the lamp cor- responds to the free water. If the free water in the soil is too far below the surface, it would be a difficult task for the water to climb to the surface as capillary water. The pull that the soil grains would exert upon the water would not be great enough to bring sufficient water to the surface soil to supply the needs of a growing plant. Near the free water the layer of moisture around each soil grain is very thick. But as we ap- proach the surface of the soil, the layers of moisture are less and less thick. Where Capillarity Is Greatest: The moisture moves upward in fine soils, such as clay, in much larger amounts than in coarse soils hke sand. This is on account of the pore spaces in the soil. c- 68 Soils and Fertilizers Pore space is the name given to the openings between the soil grains. When the pore spaces are large the water can not climb so high, for the layers of water, or films, become so heavy that the force of capillarity is soon overcome. The fact that in a fine soil the moisture may be lifted much farther than in a coarse soil accounts in part for the reason that a clay soil gives off moisture so much longer than a sandy soil. Method Of Showing Capillary Action: If you will heap up a pile of loose, dry soil in a pan, and pour water around the base of the pile, in a little while the water will have moistened all of the soil. The water passes from soil grain to soil grain until it reaches the top and moistens every grain. This capillary water is the water which the plant uses. The plant uses very little free water. .VAPOR ^.jSAWOUST FIG. 24. Hygi'oscopic water. The water which evaporates from a soil is also capillary water. As fast as capillary water is removed from soil by plants, or by evaporation, more water is supplied, drawing upon the supply of free water below. There- fore as long as we keep the supply of free water deep enough that the roots of the plants can have sufficient room, and near enough to the surface to allow capillarity to bring the water up as fast as it is used, our water supply is well taken care of. Hygroscopic Water: When soil seems very dry it still contains some moisture. Even when it is so dry that plants can not live for want of moisture, there is some water present. This water exists as very fine films around each soil grain. You can easily show that hygroscopic moisture exists in the most thoroughly air Soil Moisture 69 dried soils. To do this, take some dry soil from a field, or some dust from the road. Put a little of it in a test tube or vial and heat it gently over a flame. You will soon notice particles of moisture collecting near the mouth of the tube. This shows moisture to have been present in the soil. Hygroscopic moisture is of very little use to the farmer since the plants can obtain only a very small amount of moisture in this form. Fig. 24 shows sawdust that was obtained from a well seasoned board, giving oiF moisture. This sawdust would have seemed perfectly dry to the touch, yet the experiment shows that it con- tained some moisture. Soil Mulches To Conserve Water: A soil mulch is a layer of loose soil over the more compact soil. (See Fig. 23.) The more compact the soil is, the better it conducts water to the surface. If we break up and pulverize a few inches of top soil capillarity is checked in its upward movement when it reaches this point. Since the moisture must get in contact with the air before it evaporates, and since a mulch prevents this, the moisture evaporates but slowly. Producing a mulch is the most valuable thing we can do after each rain in order to keep the moisture in the ground where the plants can use it. This should be done as soon as the soil is fit to work. Most farmers pay no regard to weather conditions when cul- tivating their crops. They go over their corn one or four times, whichever their standard of excellence is, paying no attention to whether their mulch has been destroyed or not. As long as the soil mulch is not destroyed in a cultivated field plowing is of very little value. Cultivating a field of growing crops at the correct time to save the moisture which falls or is present, is of as much importance as any of the other operations which the farmer performs. Later you will have some experiments which show you how well a soil mulch checks the loss of capillary water. 70 Soils and Fertilizers The Water Holding Capacity of Soils: The amount of water which a soil can hold is determined by the amount of sur- face area in that soil. The finer the particles of which a soil is composed the more surface area there will be. (See Fig. 25.) FIG. 25. Pore space and water holding power of soils. Therefore a coarse sandy soil will not have as much surface area as a fine soil, and consequently will not hold as much water. In fact, a sandy soil when saturated (filled with water) will hold only about 16 lbs. of water per cu. ft., while a- pure himius soil will Soil Moisture 71 hold 26 lbs. per cu. ft. ; the other soils hold amounts varying be- tween these extremes. Fig. 25 shows different arrangements of soil grains. But we do not want our soils to be saturated with water, for this keeps out the air. We are not interested so much in the amount of water a cu. ft. of soil will hold when saturated, as we are interested in the amount of capillary water it will retain. All the water which remains after percolation has ceased is called capillary water. This includes hygroscopic water. As capillary water is found on the surface of the soil grains the greater the amount of surface in a soil the greater amount of capillary water it will hold. A fine soil not only has more soil particles, but more surface than a coarse soil, therefore, we may say that a fine soil will retain more capillary moisture than a coarse one. Obvi- ously then a soil which will contain a great deal of capillary moisture, and with a water table that will permit of a constant supply of water, is a very desirable soil. The Conservation Of Soil Moisture: The saving of soil moisture is a very important problem to the farmer, for possibly no one thing limits the average crop so often as the shortage of water. It is estimated that for each ton of mature crop pro- duced on an acre four inches of rain has been consumed. If five tons of material is harvested from an acre, twenty inches of rain has been required by that crop. In many localities very little more than this amount falls during an entire year, and in many places there is much less than this amount. When we remember that the greatest amount of our moisture is received during the seasons v/hen the plants are not growing, and that a large part of the water which the soil receives is lost by evaporation, we begin to see the importance of saving all of the water we can. 72 Soils and Fertilizers The best means of saving moisture are cultivation and drain- age. Most of the moisture that is lost from the soil is lost by evap- oration. The water is brought to the surface by capillarity, and is then evaporated into the air and lost. If after the rain falls the surface of the soil is stirred so that capillarity is stopped the water remains in the soil and is not lost. REFERENCES. Simple Exercise Illustrating Some Applications of Chemistry to Agricul- ture. United States Department of Agriculture, Farmers' Bulletin 195. Practical Agriculture, by Wilkinson. Published by the American Book Co. Davis, Productive Farming; published by the Lippincott Publishing Co. Soil Moisture 73 ^^ EXPERIMENT NO. 20. Effect of Soils on the Absorption of Substances from Solution. We have learned that clay soils are richer in plant food than sandy soils. When water dissolves the plant foods as it passes through the soil it takes this plant food away unless something retains it. Fine particles of soil absorb this plant food from the water and retain it for the use of the plants. Let us prove by an experiment that a fine soil does retain more of this plant food than a coarse soil. To do this we will have to pour water over the soils and have in this water a substance which we can see. Color some water red by adding red ink or by adding some aniline dye. You can obtain this at any drug store in packages as Diamond Dyes, etc. Do not make the water too red. Add only enough dye to color the water distinctly. Take two per- colation bottles and tie cloth over the mouths of each or plug them with cotton. Put them in the percolation rack and pour a little sand in one and a little clay in the other. Now pour a quantity of the colored solution into each bottle and collect the water which drips through. Use as many more soils as you care to in this test. Which soil permits the most color to pass through } As rain water passes through different kinds of soil, from which will it carry the most plant food ? Would it be a good plan to apply fertilizers to a sandy soil? What would happen to the fertilizers if it rained? Make a drawing of the apparatus in your note-book. Use colored crayons to show the difference in the color of the water as it comes from the different soils. In your drawing label each bottle to show what kind of soil it contained. EXPERIMENT NO. 21. Capillarity. The capillary rise of water/ as has been explained, depends upon the number and size of the pore spaces in the soil. In the following experiment you will expect the clay to lift more water than the sand. It will at first not appear to do so, although this is in fact what it does. The water which passes upward through the clay soil is covering more surface area than the water which passes through the sand. It moves upward slower at first, because the soil grains are so much closer together. In the sand the soil grains are far apart, and the water climbs rapidly. If you were to take long steps you would travel more rapidly than if you took the same number of short steps. The 74 Soils and Fertilisers water in the clay takes short steps while that in the sand takes long ones. If your columns of clay and sand are high enough at the end of a day or two you will find that the moisture has traveled farther in the clay than in the sand, although the sand was ahead at first. Try to bring out the above facts in your experiment. (See Fig. 26.) Take four percolation bottles and cover the mouth of each with cheese- cloth, or plug them with cotton. Fill each with a different kind of soil. Clay, sand, loam and humus are good ones to use. Place the bottles in the percola- tion rack so that the mouth of each bottle almost touches the bottom of a tumbler. Pour the same amount of water into each tumbler and keep the level of the water above the mouth of each bottle. Measure the height to which the water rises in the bottles at intervals of ten minutes each. Write the results in your note-book and explain why the moisture behaves as it does in each soil. Note how much water is removed from each tumbler and tell which soil takes up the most water in a given length of time. EXPERIMENT NO. 22. Distance Capillarity Will Lift Water. We have shown in a previous experiment how water passes up through a soil by means of capillarity. You will find, however, that capillarity will not lift water a very great dis- tance. In order to see how far water may sink in a soil before it is lost to the plants — -that is, so capillarity cannot bring it back again — we will perform the following experiment: FIG. 26. Capillary tubes in use. Obtain a glass tube of large bore about 1 inch in diameter and 6 or 7 feet long. If this is not to be had, ordinary glass tubing connected with pieces of rubber tubing will serve. Tie a piece of cheese-cloth over one end of the tube and fill the tube with finely pulverized dry clay soil. This soil must be well packed if it represents ordinary field conditions. Immerse one end of the tube in a pan of water and let the apparatus stand from 8 to 10 days. Soil Moisture 75 Record the height to which water rises in the tube at the end of this time. This will show you how high capillarity will lift water in a clay soil. Any water which sinks below this depth is lost to the plants. In a clay soil this depth will reach to about 6 feet. If you have the apparatus it would be well to test loam^ sand, etc., for capillarity. This experiment will help you to understand drainage, which will be taken up in another chapter. It will also help you to understand how plants live during the dry summer months. Find out all you can about the depth of the water table in your locality at various seasons of the year. Write a discussion, "The Underground Supply of Plant Moisture." EXPERIMENT NO. 23. The Three Kinds of Moisture in the Soil. The purpose of this experiment is to classify the various kinds of moisture in the soil, so that we may know what we are trying to save by tillage. To perform this experiment, obtain a percolation bottle, a pint of loam soil, some cheese-cloth and a pair of balances. Tie a cloth over the mouth of the percolation bottle. Put into it about a pint of loam soil, and j ar slightly to settle it. Now add water until it begins to drip from the mouth of the bottle. This water is free water. After the water stops dripping, remove the soil from the bottle. Weigh it. Spread it out and let dry until there seems to be no more moisture present. Weigh again. The loss in weight is capillary water. Put the dry soil in a dish and heat it in an oven for an hour or two. The heat should not be above the boiling point of water. Cool and weigh again. The loss of weight is hygroscopic moisture. What kind of water is most valuable to crops ? Can the farmer control any of these forms of soil water? Take 2 small bottles of the same size and put in one the amount of capillary water which was in your pint of soil. In the other place the amount of hygroscopic water that was present. Make a drawing of the two bottles in your note-book, and show by com- parison the amount of each kind of water in the sample of soil tested. Hygroscopic water may also be shown by taking a dry piece of wood and heating it in a test tube as shown previously, Fig. 24. The moisture which collects at the mouth of the test tube is hygroscopic water. In your note- book write a definition of hygroscopic water; of free water; of capillary water. 76 Soils and Fertilizers EXPERIMENT NO. 24. Water Consumed by a Plant. We have mentioned the fact that plants consume large quantities of water, so let us perform a simple experiment to demonstrate this fact. Take two clean glass tumblers or fruit jars, and pour exactly the same amount of water in each. Carefully dig up a healthy bunch of red clover or some other hardy plant so as not to injure its roots. Wash the soil from the roots and then immerse them in one of the tumblers of water. See Fig. 27. Mark the FIG. 27. Water consumed by a plant. height of the water in each tumbler by pasting a piece of paper on the out- side, even with the surface of the water. Place the tumblers in the window side by side. When the plant begins to wilt, possibly at the end of two or three days, remove and notice the water lost. What has become of the water that has left the tumbler which contained no plant? How much more has gone from the tumbler which contained the plant? Account for the difference in the amounts removed from the two tumblers. Soil Moisture 77 AGRICULTURAL APPARATUS AND HOW IT IS MADE. Dirt Band. In removing plants from a hotbed to outdoor beds the sudden change of conditions is likely to kill them. In order to make this change a little more gradual, a cold framC;, which is very similar to a hotbed, but kept at a much lower temperature, is often used. When we place plants in such a cold frame, it is well to place each in a separate receptacle, so that when they are to be transplanted for the last time no roots will be torn or removed and the FIG. 28. A Dirt Band. plant will receive no setback. The most convenient way to do this is by means of dirt bands. The dirt bands should be made of heavy paper and of any desired size. Fig. 28 shows one 3 inches in diameter. This is a very good size, but a smaller one will serve as well. A double thickness of newspaper serves as a bottom, the band being filled with soil and placed on the newspaper. One plant is set in each band, and when removed to the garden the soil and band are both taken and set. The paper soon decays and the plant has been transplanted without the loss of a single root. To make this dirt band, lay out a figure on heavy paper the same as shown in Plate 3, except the part below line E. F. This part is left out entirely. Put it together and your work is complete. You might make one as shown in Fig. 28 if you prefer it. 78 Soils and Fertilisers Flat for GrOTving Plants. When plants are transplanted from the hotbed they are usually planted in flats. Oft-times the seeds are sown directly in the flats. A flat is a box 3 inches deep^ 15 inches wide and 20 inches long, inside measurements. Such a flat may be made as follows: Use soft wood one inch thick for the sides of the flat. Cut and put together as shown in Fig. 29, using 6d nails. Use one-half inch material for the bottom. This material should be narrow. Wide boards warp until the soil leaks out at the bottom. When nailing on the bottom boards do not put them against one another too tight. If you do, when they become wet they will swell and bulge away from the frame. OETA/L'S OF A SO/L rLAT .ri»»!»*.jiua.aiMa^b>.sPidJi^.^Jr^-^iWJ^^ FIG. 29. A soil flat. Use the flat in your experiments in growing plants. It would be very interesting and profitable if. you could grow some early cabbage or tomato plants to be taken home and planted when the weather becomes warm. Place a layer of paper in the bottom of the flat before putting in the soil. This will prevent any soil from leaking from the box. Soil Moisture 79 Line Winder. A line winder is a very valuable little article around the farm garden where laying off the rows across the garden is accomplished by means ot string The drawing shown on Fig. 30 makes a very good winder. Use any FIG. 30. A line winder. kind of wood for this work. Soft wood given a coat of varnish when com- pleted is very good. This line winder may be fastened on a stake as shown, if it is to be used a great deal in the garden. Fig. 2, Plate 2 shows a neat line winder. 80 Soils and Fertilisers QUESTIONS AND PROBLEMS. 1. A cubic foot of soil contains 30 lbs. of moisture; 18% of it is free water and the remainder is capillary water. How many pounds of capillary water does it contain? 2. If water dissolves 10^000 lbs. of plant food from the surface foot of a soil in one week^ how much would it dissolve per day.'' How much would it dissolve in an hour.'' 3. At the above rate, how much plant food would water dissolve from the first 6 inches of a soil in one day? In one hour? 4. Eighty-four per cent of the substance in a soil will not be dissolved by water. How many pounds of soluble material in a cubic foot of clay weighing 80 lbs.? 6. If 2% inches of rainfall dissolves 260 lbs. of a plant food from the gar- den soil, how much rainfall will be required to dissolve 600 lbs. of plant food? 6. If 309.8 tons of water in a crop denoted a rainfall of 2.6 inches, how much rainfall would 452.8 tons of water in a crop denote? 7. A sandy soil having a water-holding power of 18% weighs 110 lbs. per cubic foot when dry. How many pounds of water will it hold? 8. A clay soil weighing 80 lbs. per cubic foot when dry has a water- holding capacity of 26%. How many pounds of water does it hold? 9. If a corn crop is able to reduce the water in a soil from 18% to 4%, how many pounds will it remove from a cubic foot of soil? 10. If a corn crop is able to reduce the amount of moisture in a clay soil from 26% to 12%, how much water will it remove from a cubic foot of soil? 11. Name the different forms of water in a soil. 12. Which form of water is used most by the growing plant? 13. What becomes of the moisture taken up by a plant? 14. What effect does compacting a soil have upon capillarity? 15. What kind of soil holds the most capillary moisture? 16. What is capillary water? 17. What is meant by "Water Table?" 18. How may we test soil for hygroscopic water? - CHAPTER VI DRAINAGE. A Plant" s Problem: A plant on an undrained soil has a very hard time trying to obtain the correct moisture conditions for its growth. Early in the spring the rainfall is usually so great that the plant is surrounded by too much water. Later in the season the soil becomes very dry. In order to live, the plant must adapt itself to each of these conditions which it does only with great effort and usually with a small amount of growth. Moisture conditions may be made much more desirable for the plants, as well as more convenient for the farmer by proper drainage. A Wet Soil: A wet soil in the spring makes the farmer late with his spring plowing, thus causing his crops to get a late start. Such a soil is always cold so that when the plants are started, they do not grow well. Before a farmer can cultivate a wet soil, the weeds get a start and are then very hard to overcome. The roots of a plant in a wet soil have a small chance to ob- tain the air which they need, and oft-times can be seen growing above the ground, trying to escape the extra water. Therefore, unless we drain the soil so that it will rid itself of this extra moisture, our ordinary plants will have a very poor chance to grow successfully. The Value of Drainage: The only way to remove surplus water from a field that is practically level is by drainage. The drainage of such a soil admits air to the roots of the plants. It deepens the layer of soil from which the roots can obtain food. In time of drought, plants growing in a well drained soil do not 81 82 Soils and Fertilizers suffer for moisture as much as plants growing in an undrained soil. Good drainage permits of early tillage and increases the plant food in the soil. Another important point to be considered in draining the soil is that a well drained soil becomes warm earlier in the spring, giving the plants a better chance to grow. Drainage Gives Roots More Room: If a soil is undrained the water usually sinks only a short distance below the surface. If we dig down a few feet we find that the soil is completely filled with water. This water level, as we have learned, is called the water table and in an undrained soil it lies very near the sur- face, especially in the spring and fall. Since the roots of a plant will not grow below this water table, they have only a very little room for growth in such a soil. By draining this same soil the Drainage 83 roots will penetrate deeply, and when the dry days of summer come the great network of roots is able to obtain water by cap- illarity. Therefore the plants do not suffer so much for moisture as they would have suffered if the soil had not been drained. Fig. 31 shows an undrained field. Drainage Increases Weathering Action: To show what water does in a soil let us notice what happens to a solid lump of sugar if placed in a tumbler of water. The sugar first crumbles from a solid mass into a larger number of fine particles. Finally if there is not too much sugar it will disappear altogether. This is called "going into solution." When water passes through a soil it is treating the soil just as it treated the sugar. It is breaking down the large soil particles and carrying away with it much plant food and also much that is poisonous to plants. No difference how much water a plant had if some water did not pass through the soil and carry away plant poisons with it, the plant could not live long. Drainage Raises the Soil Temperature: Through the winter the ground remains frozen and filled with water. If the ground is undrained, when spring comes, this cold water remains in the soil for a long time. This water becomes heated very slowly, so that the soil is cold until late. If such a soil is drained, however, the warm spring rains soak into the soil taking the place of the cold water which the drain removes. This change of water increases the temperature very rapidly, and such a soil becomes warm much earlier than an undrained soil. Also in an undrained soil the water escapes by evaporation at the surface Drainage FIG. 32. rives roots more room. 84 Soils and Fertilisers and the evaporation of this water makes the soil cold. Drainage would be worth while for the difference it makes in soil tem- perature if it did no other thing. Indications That Drainage Is Needed: All good land should be well drained, either naturally or by artificial means. In most cases it is only partially drained naturally, and in some cases not at all. If the subsoil is very loose and open, nature has re- lieved us from concerning ourselves about the drainage of such land. In some places the surface is so hilly that rainfall is almost all carried away at or near the surface. Such a soil would not need tile drainage. "tj^ Almost always a soil which needs drainage is weedy. Weeds have adapted themselves to conditions under which cultivated plants can not live, and if we find a field where our common plants are crowded out year after year by weeds we can rest assured that such a soil needs drainage. ^^y If we find mosses and sedges growing on a soil, it indicates the need for drainage. A soil which is undrained will generally refuse to produce a crop of clover, on account of the injurious substances which are left at the surface by the evaporation of moisture. Therefore, if a soil will not produce a clover crop, drainage is one of the first things that should be looked to for the failure. Drainage Prevents Heaving: Crops can not thrive on a soil that becomes filled with water. In winter the freezing water in the soil expands, forcing the soil grains upward, for that is the only way they can move. When the ice melts the soil grains settle close together again. Each time that this happens the roots of the plant are lifted a little farther out of the ground. This breaks off all of the fine rootlets which are so necessary for the plant. When there is considerable freezing and thawing dur- ing a winter, plants are lifted almost entirely out of an undrained Drainage 85 soil. It is absolutely impossible for them to live under such conditions, and the only way such a soil can be made valuable is by drainage. The accompanying illustration, Fig. 33, shows what happens as a result of the heaving of the soil. Many farmers have tried to grow alfalfa on this kind of soil. Can you see why they have failed? History of Drains: People have long realized the need of drains, but until rather recent j^ears no permanent methods were devised for successfully draining a soil. The open ditch was PIG. 33. The stakes in the above picture were driven with their tops even with the surface of the ground in the fall. The winter's freezing and thawing lifted them almost entirely out of the ground. Do you see why plants cannot thrive in such a soil? the only method used for a long time, but such a ditch took up a great deal of room and was always needing repair. So men began to search for something better to serve as a drain. When this necessity for drainage was first realized in America, hollow tile were not to be had. Instead men tried to make drains by burying bunches of poles, end to end. The spaces between the poles left open places where the water could pass 86 Soils and Fertilisers and such drains were all right until the poles rotted. To over- come this difficulty the idea of taking the rocks which had to be removed from the fields and making drains of them was started. Men dug open ditches, placed a few layers of boulders and rocks in the bottom of them and then filled them with soil. The stones like the poles left spaces, through which the water could flow. Such drains worked very well. Later the use of hollow tile was adopted. Hollow Tile For Underground Drains: The first burned clay tile used here were shipped to America from Scotland. Most people made fun of them and said that they would ruin the soil in which they were placed. The average farmer at that time and for a long time after could see no use or value in drain- age. For this reason and on account of the expense the use of tile drains was very slow in being adopted. At the present time the value of drainage is well recognized, and although still ex- pensive, excellent systems of drains are placed on all of the more modern farms. Hollow tile were almost entirely made of burned clay until quite recently. Large quantities of them are now made of con- crete. Larger tile are made of concrete than it is possible to make of burned clay. However, the smaller tile can still be made cheaper from burned clay than from concrete. How Drainage is Accoiiiplished: All moisture leaves the soil either by passing over the soil or through it. That moisture which passes over a field without soaking into the soil is said to have been removed by surface drainage. In the spring, when the rainfall is heavy, a great amount of water runs off of a field as surface water. This water not only does no good, but it does a great deal of damage. It carries as sediment a great number of fine soil grains which, as has been mentioned, are the best part of the farmer's field. After a flood or a heavy rain you often see quantities of rich black soil along the roadsides. This Drainage 87 is valuable plant food which has been washed from the neighbor- ins- fields. The water which runs off of a field as surface water does not help to decay or break up the subsoil, which is one great thing that water does in the soil. Possibly the greatest advantage of having water seep through a soil, and flow through a drain is the fact that it dissolves and carries away many poisonous and injurious substances called salts, which are continually accumulating in the soil. Just as water is used in your home to wash away undesirable dirt, so it behaves in the soil by removing these poisonous substances. As mentioned previously, plants can not live very long where there is no passage of water through the soil. For the above reasons it is much better to have the water which falls pass through the soil, rather than over it. Underground Drainage By Covered Drains: Underground drainage has to do with all water which passes through the soil and is removed through some underground outlet. Underground drainage takes place naturally in most soils, but in many soils it is not as effective as it should be. In order that underground drainage shall be more effective, the farmer is oft-times com- pelled to supply some artificial drainage. Percolation (seeping of water) as you know depends upon the structure of the soil. If the soil or subsoil is hard and packed the water gets through very slowly. In such soils the drains must be close together to remove the extra water from all parts of the soil. If, on the other hand, the subsoil is coarse and open the water can percolate very rapidly and it needs no drainage. The rapidity with which water is able to percolate through a soil determines the depth to which we can place our underground drains, as well as the value of both open and closed drainage systems. Drainage By Means of Open Ditches: Drainage by means of small, open ditches is rapidly going out of existence. This 88 Soils and Fertilizers is as it should be, for open ditches are a nuisance to any farmer; besides it is expensive to maintain them. The ground which an open ditch occupies will yield larger returns if replaced by a covered drain and tilled. Open drains scatter weed seed and cause work and worry each year. The expense of all this is ul- timately greater than the cost of tiling such a ditch. Some farmers maintain that the open ditch is very valuable as a source of water supply for live stock. However, in this respect, tile drains may be made even more valuable than open drains. By leaving a small runway down to the water and then leaving out a few tile, stock can obtain water as long as water flows through the drain. If this is done the earth may be dug out a little below the tile, and clean gravel put in its place. The ends of the open tile should be screened so that nothing injurious will get into the openings to clog the drain. Such an arrange- ment makes a more convenient and cleaner watering place than can possibly be obtained by an open ditch. A tile drain, unlike an open drain, compels the water to pass through the soil, and, as has been stated, this is a decided advan- tage. However some subsoils are so hard that water is unable to soak through. Where such a soil exists, open drains must be used until the structure of the subsoil is modified. Laying a Drain: The tile used in laying a drain should be strong and well burned. A cracked or damaged tile should not be used, for it is sure to give trouble at sometime. If a tile will not make a good joint on account of a broken or crooked edge it should not be used. If it is used the joint should, at least, be protected with a piece of a broken tile. It is poor economy to use for drainage a tile less than 4 inches in diameter. Tile smaller than this dimension are easy to clog and do not perform as much service as they should. It costs but very little more to use larger tile and they can be relied upon to give more and better service. In laying a drain great care Drainage 89 should be exercised to get the tile in line, for any places where the tile do not join properly furnish spaces for dirt to lodge and clog the drain. This is especially true of the small tile. Distance Apart and Size of Drains: The distance of drains from each other and the depth at which they should be placed depends upon the character of the soil. On light porous soils they should be deeper and farther apart; on heavy soils they should be close together and near the surface. Tile 4 inches in diameter laid three or four feet deep, from 80 to 100 feet apart, under ordinary conditions, make a very good drainage system. In laying out a drain provision should be made for a fall of at least 2 inches in 100 feet. Less than this amount is undesirable, and less than 1 inch to 100 feet is unsatisfactory. It is best to obtain the services of a drainage engineer if the fall is slight and the drainage system complex. For ordinary work a farmer who can use a level should be able to lay out the drain. Laying out a tile drain and figuring the fall which it should have presents a practical problem, which would make a very good field exercise for a class. Staking for a Drain : Take a number ( a dozen or more ) stakes, one inch square and three or four feet long, an axe, a level, a tape line and a ten or twelve foot straight edge, to a field that has an open stream running through it. Go to a portion of the field that is quite distant from the stream and there start your tile ditch. First drive a stake to mark this point (the source). Then go down along the stream and near the water's edge drive another stake which is to show where the end (outlet) of your drain is to be. Now proceed as follows : About ten feet from the stake at the source of the proposed drain drive another stake in direct line between it and the one at the outlet. In a like manner at regular intervals (say fifty 90 Soils and Fertilizers yards) drive the remainder of the stakes, being sure to keep them in line with the first two driven. Now get the first stake driven (the one at the source) straight up and down and rigid. To do this you may have to drive it farther into the ground. Then drive the stake, which is ten feet away from this one, down until the tops of the two stakes are exactly level. You can tell when they are correct by laying the straight edge across the two stakes and testing with the level. After the first two stakes are perfectly level, have a boy sight over the tops of them, while another boy makes pencil marks on all of the rest of the stakes. These marks should be made at a height which the person sighting designates as being level with the stakes over which he is sighting. When all of the stakes are marked except the two over which the sighting was done, we are ready to establish the depths. This can be very easily done. First decide how deep the drain should be at the mouth. Usually a short distance above the water in the open ditch is about the right height for the outlet of the closed drain. Measure the distance from the line on the stake at the outlet, to the depth you want the bottom of the drain ; for illustration, say seven feet. Write this depth on the stake. Now if you want a fall of one inch in one hundred feet, for example, and your next stake is one hundred and fifty feet away, the distance from the line on that stake to the bottom of the drain will be one and one-half inches less than seven feet, or six feet ten and one-half inches. Write this number on the second stake. You can readily see that it would be one and one-half inches less to the bottom of the drain here than it would be fifty yards farther down. In a like manner put the correct figures on all of the rest of the stakes. The figures on each stake show the distance from the line on that stake to the bottom of the ditch. This work should require several recitations and the drain should be designed on Drainage 91 paper as well as laid out in the field. The drain should be so laid out that it would do its full share of work if it were con- structed. How Water and Air Get Into a Drain: The water enters a tile at the joints, and does not seep through the tile as is popu- larly supposed. For this reason, we need to have good joints (but not watertight) to prevent the water from carrying dirt into the drain. We have stated that the air which gets into a soil through a drain is one of the benefits of a drain. FIG. 34. How water and air get into a drain. In order that a tile drain may admit a great deal of air to a soil, it is best to have the source of a line of tile open to the air. This can be accomplished by standing tile on end at or near the source of a drain and letting the top tile come just above the surface of the soil. This tile should be screened to prevent rab- bits, etc., from getting into the drain. It is best brought to the surface along a fence, or at some place where it will not be in the way of farming operations. Such an arrangement at the source of a drain permits a free flow of air through the drain thus aerating the surrounding soil to a great extent. 92 Soils and Fertilizers Soils That Should Have Drainage: There is always a doubt in the farmer's mind about the advisabihty of putting an under- ground drain in his field. While the special conditions of every field must be considered before we can know positively regarding that field, yet the following is a list of places where it is almost always wise to put a tile drain: (1) Flat lands along streams that overflow in the spring. On such lands we must lower the level of the water in the soil as soon as possible after the overflow. If we do not drain such a soil we can not get our crops planted early, or save any crops that may have been planted before the overflow. (2) Flat land having a clayey subsoil. On such a land nat- ural drainage can not take place, so artificial drainage must be supplied. (3) Low places or valleys in hilly land. The water must be drained from such places to remove the extra water that flows from the higher land all around. (4) Swamps and Marshes. Such places are wet almost all year and unless drained they are of little value. When such soils are properly drained they oft-times make our very best soil. Drainage EXPERIMENT NO. 25. 93 :p Effect of Lime on Turbid Water. A clay soil will become more open and in better condition if it contains lime. This lime unites with the carbon dioxide of the air and flocculates (sticks together) the clay soil particles. A very excellent experiment for showing the action of lime on clay may be performed as follows: Stir a tablespoonful of clay with a pint of water. Let stand a moment and then fill two glass vessels with the muddy water. Glass tumblers or beakers are very good for this purpose. Into one of the glass vessels put a teaspoonful of lime and shake or stir it thoroughly. Leave the second vessel untreated^ except to stir thoroughly. Let both vessels stand and observe them every few seconds to note any changes that may occur. Explain what happens. Account for this change. Write a discussion upon the value of lime. (See Fig. 35.) EXPERIMENT NO. 26. The Effect of Lime on Soils. Take two pans and make a stiff bat- ter in each by stirring clay and water together. Have the pans of clay to the same degree of stickiness^ as nearly as possible. Now stir a tablespoonful of lime in one of the vessels, adding a trifle more water if necessary. Stir until the lime is thoroughly mixed with the soil. FIG. 35. The effect of lime on turbid water. Muddy water to which Ume was added. Muddy water without lime. Leave the other pan of soil untreated and set both pans aside to dry. Place them where they will get as much sunshine as possible. When thor- oughly dry, break or crush the two pans of soil and note the relative hardness of each. Explain in your note-book the results of your experiment. 94 Soils and Fertilizers EXPERIMENT NO. 27. Effect of Drainage Upon Plant Grorvth. Obtain two tin cans, and with a nail punch holes in the bottom of one of them. These holes will provide drainage. Fill both cans with rich soil and moisten the soil until it is saturated. Plant 5 to 10 seeds in each can, and cover them about 1 inch deep. Label and set aside, water them regularly and alike for a week, examining occasionally to note progress. Describe in writ- ing the value of drainage upon germination. A B FIG. 36. A — Hard puddled clay soil without lime. B — The same soil after having lime added, and being exposed to winter weather. EXPERIMENT NO. 28. Temperature of Drained and Undrained Soils. Obtain two tin cans, and with a nail punch holes in the bottom of one of them. Fill both cans with rich soil and saturate each soil with moisture. Leave both cans exposed to the air for a day. At the end of a day insert a thermometer into each soil and observe the temperature. Take readings every hour for several hours. What can you say of the temperature of a drained soil compared with an undrained soil? ■'^''^' VPT i I I ^-s= 2=£=S^ ^1 ^/i£- xr-o-a o-'O-a r/G /-sP€c/mEA/ case: r/GZ'SPEcmE/i mou/iT -et/yofyfi} tape AC / o O O O O O /y» z /iOG 11 Q tD /Y09 o O /fOJ/ O O AfO/3 o O O /io/6 O >^