SOIL CONDITION AND NITRIFICATION 



419 



ing been converted into the form of nitric acid, it im- 

 mediately combines with available bases in the soil* 

 forming salts, all of which are very easily soluble, and 

 which are carried in solution by the soil water. In a 

 region of large rainfall, the removal of nitrates in the 

 drainage water is very rapid. Hall states that nitrates 

 formed during the summer or autumn of one year are 

 practically all removed from the soil of the Rotham- 



Fig. 113. The modern, small, eight-shovel riding cultivator. 



sted fields before the crops of the following year have 

 advanced sufficiently to utilize them. It was formerly 

 customary to fertilize with ammonium salts in the 

 autumn, but the drainage water showed on analysis 

 such a large quantity of nitrates during the months 

 intervening between the time of fertilizing and the 

 opening of the growing season that the practice was 

 discontinued. 



In regions of less rainfall or of greater surface 

 evaporation, the loss in this way is less, reaching a 



