26 THE PLANT FOOD SUPPLY 



ANIMAL MANURES 



Animal manures are especially valuable in vegetable garden- 

 ing, for in addition to the plant food they contain they supply 

 a large amount of organic matter to the soil, which, as indicated 

 above, assists in the liberation of plant food already present in 

 the soil. This is accomplished by means of the solvent effect of 

 the organic acids which are formed during the decomposition of 

 the manure. 



Animal manures differ considerably in the amount of plant 

 food they contain. Their composition depends chiefly upon the 

 kind of manure (whether produced by horses, cattle, sheep, swine 

 or poultry), the amount of litter it contains, and the conditions 

 under which it has been kept. Manure that has been allowed to 

 leach or to become overheated has usually lost much of its plant 

 food. However, for vegetable gardening purposes, the mechanical 

 condition of manure may be of more importance than its plant 

 food content. Part of the plant food may be sacrificed in order 

 that the remainder may be rendered immediately available to the 

 plants. '^ Well-rotted manure" is better adapted for use on many 

 garden crops than is fresh manure; yet considerable plant food is 

 usually lost during the process of rotting. 



Compost. — Very fine, thoroughly-rotted manure or other 

 organic matter is known as ''compost." It is prepared by piUng 

 up the manure or other material in long, low piles six or eight feet 

 wide and two to four feet high (Fig. 11). This is done from six 

 months to a year before the compost will be needed for use. The 

 sides of the pile are made as nearly perpendicular as possible 

 and the top is flattened so that rains will soak in instead of run- 

 ning off. If the weather is dry, water may be applied. Sometimes 

 the pile is made of alternate layers of earth, sod or muck, and 

 manure. In this case there is less loss of fertility from the manure. 

 A few weeks before the compost is to be used, the pile is cut down 

 and the material repeatedly turned and mixed until the manure 

 is thoroughly decomposed and the entire mass is of fine texture. 

 Formerly this work was done by hand with a fork or spade and 

 entailed a large amount of labor. Now some of the most progres- 

 sive gardeners do all this turning of the compost with a disk and 

 plow. The pile is worked over three or four times at intervals of 

 one or two weeks. Compost is especially desirable for use in seed 

 beds, melon hills, for top dressing a growing crop, or for any 

 other purpose where very quick action of the plant food is desired. 



