BARNYARD, STABLE, GREEN MANURES 77 



relative numbers and values of milch cows as compared with all other 

 cattle. 



ANIMALS IN THE UNITED STATES IN 1910 AND ESTIMATED VALUE OF 

 THEIR MANURE. 



Manure is valuable because: (1) it contains the three essential ele- 

 ments of plant food, namely, nitrogen, phosphorus and potassium; (2) 

 it furnishes organic matter which is converted into humus in the soil and 

 materially improves the physical condition, water-holding capacity and 

 chemical and bacterial activities in the soil; (3) it introduces beneficial 

 forms of bacteria in the soil and these multiply and become increasingly 

 beneficial as their numbers increase. 



As a Source of Plant Food. The composition of manure varies with 

 the kind of animals producing it, the age of animals and the amount 

 and quality of the feed they consume. The manure consists of the solid 

 excrements and the liquids or urine. These differ in their composition. 

 The urine is the most valuable part of the excreta of animals. The aver- 

 age mixed stable and barnyard manure contains approximately ten pounds 

 nitrogen, six pounds phosphoric acid and eight pounds potash in each ton 

 of manure. The solid portions consist chiefly of the undigested portions 

 of the food consumed, together with the straw or bedding that has been 

 used in the stables. The solid portions contain approximately one-third 

 of the total nitrogen, one-fifth of the total potash and nearly all of the 

 phosphoric acid voided by animals. The urine contains about two-thirds 

 of the total nitrogen, four-fifths of the potash and very little of the phos- 

 phoric acid. The elements found in the urine are insoluble. They are 

 not immediately available as food for plants, but become so more quickly 

 than the constituents in the solid portions. 



Of the nitrogen in barnyard manure, that in the urine will be most 

 readily available; that in the finely divided matter of the feces will be 

 more slowly available; and that in the bedding will be most slowly avail- 

 able. For this reason the availability of the nitrogen in manure when 

 applied to __tbe soil is distributed throughout a comparatively long period. 

 Availability will vary greatly with the nature and treatment of the manure. 



* Estimated ralue based cm relative numbers and values of milch cows and all other kinds of cattle, 



