LOSS OF SOIL NITROGEN 



327 



Hall has estimated the loss of nitrogen from certain 

 drained plats, of the Rothamsted Experiment Station. 

 This estimate is based upon the concentration of the 

 drainage from the different plats, of which there was 

 no record of total flow, but for which the measurements 

 of flow from the lysimeter draining 60 inches of soil 

 were taken, and the total loss of nitrates calculated 

 on this basis. Estimated in this way, the effects of sev- 

 eral different methods of manuring are shown in the 

 accompanying table. 



Table XLVIII 

 Pounds per Acre Nitric Nitrogen in Drainage Water 



Treatment 



Unmanured 



Mineral fertilizers only 



Minerals + 400 pounds amnion, salts . . 

 Minerals + 550 pounds nitrate of soda . 

 Minerals + 400 pounds ammon. salts 



applied in autumn 



400 pounds ammon. salts alone 



400 pounds ammon. salts + sulfate of 



potash 



Estimated drainage in inches 



1879-80 



Spring 

 sowing 



to 

 harvest 



1.7 



1.6 

 18.3 

 45.0 



9.6 



42.9 



19.0 

 11.1 



Harvest 



to 

 spring 

 sowing 



10.8 

 13.3 

 12.6 

 15.6 



59.9 

 14.3 



16.4 



4.7 



1880-81 



Spring 

 sowing 



to 

 harvest 



0.6 



0.7 



4.3 



15.0 



3.4 

 7.4 



3.7 



Harvest 



to 

 spring 

 sowing 



17.1 

 17.7 

 21.4 

 41.0 



74.9 

 35.2 



25.3 



18.8 



This table, in addition to confirming the statements 

 already made in regard to the loss of nitrogen in drain- 

 age waters, also shows how closely the supply of avail- 

 able nitrogen was used by the crops on those plats, 



