PRINCIPLES OF MANURING 99 



entirely absent if a cruciferous crop has not 

 occupied the land oftener than, say, once in 

 eight or ten years. 



Against these advantages of bare fall ow- 

 ing, apart from the loss of nitrates, are to be 

 put the heavy expenses which, with cultiva- 

 tions, rent, and rates, often amount to 5 or 

 more per acre. No single wheat crop could 

 bear this outlay, in addition to its own costs, 

 but, of course, the effects of a bare fallow 

 are not confined to the crop immediately 

 following, but are shared by several. 



CHAPTER V 



THE PRINCIPLES OF MANURING THE 



NITROGENOUS MANURES 



ON tillage and grass farms alike, the 

 selection and application of fertilizing sub- 

 stances is one of the most important matters 

 that demand the farmer's attention. Nowa- 

 days there are but few farms, with any 

 considerable amount of land under the 

 plough, where artificial manures are not 

 employed to a greater or less extent. It is 

 only on purely pastoral hill farms that 



D 2 



