312 BOARD OF AGRICULTURE. [Pub. Doc. 



stroyers " live away from the air and do not need it. Tiiey 

 are dependent, however, on food of a certain kind, and must 

 have plenty of it, otherwise they become inactive and can 

 do no damage, though millions of them may exist in the 

 interior of the manure pile. One of their principal foods, 

 the non-nitrogenous material of the litter, they cannot use 

 as food until it has been made soluble by a third class of 

 bacteria, which causes the rotting of the litter. Nitrates are 

 also indispensable for their nourishment. If, therefore, they 

 are deprived of either one of these constituents of their diet, 

 they either die or at least become harmless. 



The work of the ' ' nitrate formers " is beneficial ; it con- 

 verts organic nitrogen into nitrate, a most available form of 

 plant food. Half-rotted manure contains nitrogen largely 

 in this form. The work of " nitrate destroyers" is destruc- 

 tive ; it removes the soluble nitrates from the manure ; it 

 converts half-rotted manure into well- rotted manure. In 

 this way the diflerent efiects produced by manure in the 

 three different conditions are explained. The nitrogen in 

 fresh manure is largely organic, and not immediately avail- 

 able ; it therefore has a slower and less effect than half-rotted 

 manure. The nitrogen in half-rotted manure is largely in 

 the form of nitrates, and this is available. The nitrogen in 

 well-rotted manure has all been converted into nitrates also, 

 and was once available, but has subsequently been lost in 

 the air. This is why the well-rotted condition is the least 

 valuable of the three. 



Of the three common conditions of barnyard manure, 

 half-rotted manure is the most valuable and well-rotted 

 manure the least, because of their relative amounts of nitrates. 



Manure should be kept packed away from the air as tightly 

 as possible, and, if rotted, should be plowed under just be- 

 fore planting, otherwise, several months before that time. 



The more litter used in the manure, the greater liability 

 to loss of nitrogen. 



The use of bedding material free from decomposable or- 

 ganic matter is a means of protection against loss of nitrogen. 



