230 



NITEIFICATION 



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 l)y 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 



