S 639 .F5 Copy 1 [TED STATES DEPARTMENT OF AGRICULTURE MISCELLANEOUS PUBLICATION No. 136 WASHINGTON, D. C. JANUARY, 1932 CONSERVATION OF FERTILIZER MATERIALS FROM MINOR SOURCES #^ . 1 ' '\ % j^'l^ I^p ^Si UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1932 For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents. Mosogrart N CONSERVATION OF FERTILIZER MATERIALS r FROM MINOR SOURCES By C. C. Fletcher, Associate Chemist, Division of Soil Fertility, Soil Investigations, Bureau of Chemistnj and Soils CONTENTS Page The value of composts 1 Making composts 1 The use of chemicals in composts 2 Some practical suggestions 3 Coal asbhes and spoiled feeds 5 Analyses of various materials. 5 THE VALUE OF COMPOSTS In maintaining soil fertility the periodic addition of organic matter plays an important part. Composts are constantly being made through the rotting of leaves, twigs, roots, and other organic matter as shown by the photograph on the title-page of this publication. Composts of various substances may help supply organic matter, and they also often supply nitrogen, phosphoric acid, potash, and other elements needed by plants. The general farmer is forced to rely principally on stable manure, commercial fertilizers, and green-manure crops, but the small farmer, or suburbanite, can often use to advantage a great variety of waste substances which are valuable as fertilizers but obtainable in such small quantities as to make them unprofitable to handle on a commercial scale. In butchering hogs on the farm the blood, entrails, and several other parts are frequentl)^ wasted. These are all valuable fertilizers. Kitchen waste, provided it is free from soap, washing powders, glass, tin cans, and other injurious materials, should be fed to animals if possi])le; but if no chickens or pigs are kept, it should be used in composts as fertilizer. Dry leaves, weeds, sw^eepings from the house and barn, cofi'ee grounds, banana peelings, soot, and wood ashes, all have fertilizer value. These and many other materials should be saved and either applied direct to the soil or composted with manure before using. The value of composts has been i-ecognized for centuries in all agri- cultural countries, and compost heaps are conspicuous in the rural villages of European countries and are the prmcipal means of keeping up soil fertility in China. MAKING COMPOSTS It is possible to make composts in various ways, but the most common way is to alternate layers of stable manure with waste and absorbent materials, such as dried leaves, peat, muck, and sod. The pile is kept moist and turned several times in order to thoroughly mix the compost. The outside of the pile may be kept covered with soil. Where possible, at least half the material used should be manure, but if this quantity can not be obtained a small amount should be used, in any event, to inoculate the heap with the 88371°— 32 1 2 MISC. PUBLICATION 136, U. S. DEPT. OF AGRICULTURE bacteria of decomposition. In the principal cities dried bagged animal manures can be purchased. Another method of composting, where hogs are available, is to keep the animals in a tight pen, the floor of which is covered with a layer of straw or leaves. Absorbent material is added as needed, and the residues of foods, weeds, and cull vegetables, together with the manure, are thoroughly mixed and trampled by the hogs. If care is used this practice will yield a large amount of valuable compost, although the procedure is not recommended from a stock-raising standpoint. Where very fine material is desired, well-rotted compost may be screened, and the parts which are not tlioroughly broken down removed. (Fig. 1.) The screened material is particularly valuable where small and delicate plants have been set out or are being culti- , Figure l. — Screening well-rotted compost for special use vated. Such material may be used on lawns where the coarser material is too unsightlv and