582 SOILS: PBOPERTIES AND MANAQUMMNT 



485. Individuality, condition, and age of animal. — 



Various animals differ in capacity, some retaining much 

 more of the elements contained in the food than do others, 

 and consequently producing a poorer manure. The 

 service to which the animal is subjected is also a factor. 

 A milch cow will certainly utilize more nutriments than 

 an animal not in that condition. Age is perhaps more 

 accountable for variation in farm manure than either of 

 the other two causes. A young animal gaining in muscle 

 and bone is storing away large quantities of nitrogen, 

 phosphorus, and potash, and producing a manure corre- 

 spondingly poorer in these ingredients. 



486, Food of animal. — Since the animal will retain 

 only a certain quantity of the food elements, it is reason- 

 able to suppose that the richer the food, the richer will 

 be the corresponding excrement, both liquid and solid. 

 Such has proved to be the case. Wheeler,^ in studying 

 the rations of chickens, found the following difference 

 in the manure produced : - 



Ration 



Percentage of 



H2O 



N 



P 



K 



Fresh hen manure (nitrog- 

 enous ration) - . . 



Fresh hen manure (car- 

 bonaceous ration) . . 



59.7 

 55.3 



0.80 

 0.66 



0.41 

 0.32 



0.27 

 0.21 



From Ohio,^ where the production of manure has been 

 most thoroughly investigated, the following data may be 

 quoted : — 



1 Wheeler, W. P. Poultry Feeding Experiments. Rept. 

 New York (Geneva) Agr. Exp. Sta., No. 8, p. 62. 1889. 



2 Thorne, C. B., and others. The Maintenance of Fertility. 

 Ohio Agr. Exp. Sta., Bui. 183. 1907. 



