506 NATUEB AND PROPERTIES OF SOILS 



such a comparison, five eharact eristics are outstanding: (1) 

 the moist condition of manure, (2) its low grade, (3) its 

 unbalanced nutrient condition, (4) its variability, and (5) 

 its rapid fermentative and putrefactive processes. These 

 characteristics, neither present nor desirable in ordinary fer- 

 tilizers, place farm manure in a class by itself as to its hand- 

 ling, storage, and field utilization. 



0£ the above points, the first three may be disposed of 

 quickly. Average farm manure, whether fresh or well-rotted, 

 contains from 70 to 85 per cent, water. A ton of average 

 mixed manure when applied to the land carries but 12 pounds 

 of ammonia, 5 pounds of phosphoric acid, and 10 pounds of 

 potash to the ton. Approximately one-half, one-sixth, and 

 one-half, respectively, of these constituents are readily avail- 

 able. Farm manure is, therefore, low-grade on two distinct 

 counts. Moreover, its readily available nutrients approximate 

 a ratio of about 6-1-6, a marked contrast to the 2-8-2 often 

 given for the average ready-mixed fertilizers on the market. 

 Obviously, manure is much too low in phosphoric acid for its 

 content of active ammonia and potash. The variability and 

 decomposition of farm manure will be considered separately. 



287. Variability of farm maiUure. — The manure pro- 

 dnced on the average farm will obviously vary in its char- 

 aeter and composition from time to time. The factors re- 

 sponsible may be listed as follows: (1) class of animal, (2) 

 age, condition, and individuality of animal, (3) food, and 

 (4) the handling and storage which the manure receives be- 

 for it is placed on the soil. 



The differences in composition due to class of animal have 

 been adequately disposed of in previous paragraphs. In ad- 

 dition, it is obvious that the age and condition of any 

 animal within a class will influence the character of the ex- 

 crement produced. A young animal gaining in bone and 

 muscle will retain large amounts of nutrients, and the manure 

 will be correspondingly poorer in dry matter, nitrogen, lime, 



