362 ANNUAL REPORT OF THE Off. Doc. 



(c.) The Relation of Denitrifieation to Cultivation. 



It has been stated that denitritication may take place either in the 

 presence or absence of atmospheric air. 



With the presence of some form of easily assimiliable organic mat- 

 ter, it may take place under any condition of aeration. 



Nitrification is the opposite and antagonistic process to denitri- 

 fieation. Furthermore, the conditions which are favorable to the 

 former are inimicable to the latter. 



The question of denitrifieation and loss of nitrogen in soils is one 

 about which much has yet to be learned, but it is generally believed 

 that under ordinary conditions it is of no particular importance. 

 At least this much may be said, that if the agriculturist will main- 

 tain those conditions which are favorable to nitrification, any pos- 

 sible loss of nitrogen by the opposite process can be disregarded. 



Hence cultivation, which effects the rapid destruction of easily 

 assimiliable organic compounds, leaves little opportunity for the 

 denitrifying bacteria to carry on their destructive work. 



8. The Loss of Nitrogen From Stable Manures and its Conservation. 



It has been stated that denitrifieation and loss of nitrogen is com- 

 paratively rapid in stable manures, because of the abundant presence 

 of denitrifying bacteria and of easily assimiliable organic compounds 

 which furnish food to the latter. It has also been noted that straw 

 mixed with urine and excrement also assists the process by fur- 

 nishing an easily assimiliable carbon compound in the form of pen- 

 tosans. 



So deleterious is the action of straw that it has been suggested, as 

 a feature of good farm practice, to keep the manure and litter sepa- 

 rate, or to see to it that as little straw as possible becomes mixed with 

 The urine and faeces. 



To what extent this is practicable must be left to the practical 

 agriculturist to determine. But taking conditions as they ordinarily 

 exist, i. e., with straw forming a considerable proportion of the 

 manure proper, and with the natural losses of nitrogen which must 

 take place to confront us, how can these be reduced to the minimum. 



There are two methods for conserving the nitrogen content of stable 

 manure, first, by the exclusion of air and second, by the use of pre- 

 servatives. 



