230 



NITRIFICATION 



Neither the percolation nor the total quantity of nitrogen 

 removed differ much for the 40-inch and the 60-inch gauges ; but 

 owing to the greater amount of water retained by the deeper 



Jan. Feb Mar. April May June July Aug Sept. Oct. Nov. Dec. 



FIG. 45. Rainfall, Percolation, and Nitrogen as Nitrate in Drainage through 

 20 inches of Soil. Rothamsted. 26 years (1878-1903). 



soil the drainage from the 60 -inch gauge is more uniform in 

 concentration throughout the year, the main discharge also 

 comes a little later in the year. 



Inspection of the curves shows how great is the variation 



