PLANT FOOD 53 



face. In this connection it is well to remember : first, 

 that the proportion of soluble constituents in fresh 

 manure is less than in rotted; second, that fresh 

 manure does not contain any considerable amount of 

 ammonia. 



When fresh manure is spread in the winter, before 

 the nitrogen of the urine and dung is converted into 

 ammonia by the process of decomposition, there is 

 little or no loss into the air; further, ammonia will 

 not form when the temperature reaches the point 

 which usually prevails during the winter months. 



There is one possible source of serious loss, how- 

 ever, when manure lies exposed on a sloping or hilly 

 surface. Under these conditions a portion of the 

 soluble constituents of the fresh manure may be 

 washed out and carried away over the'surface. It is 

 generally preferable to spread manure on pasture, 

 meadow or stubble ground where there is less danger 

 of washing and consequent loss. 



On the other hand, well-rotted manure is a highly 

 concentrated product. Certain anaerobic ferments act 

 to destroy the woody fiber in the manure and thus the 

 proportion of nitrogen, phosphorus and potassium, 

 the valuable fertilizing elements, may be larger in 

 well-rotted manure than in the fresh manure. This 

 shrinkage in volume, which occurs when manure fer- 

 ments, is an important saving in the cost of distributing 

 the proditct upon the field. 



Thoroughly rotted manure is esteemed highly 

 because it may act more quickly than fresh manure. 

 A large proportion of the elements of fertility are in a 

 condition to be taken up by the roots of plants. In 

 addition the humus of well-rotted manure would in 

 case of drouth, serve a better purpose than that of 

 fresh unfermented litter. 



