VIII.] 



NITRATES IN DRAINAGE WATER 



227 



plot received no mineral manures, and therefore grew 

 but a scanty crop. The losses during the winter months 

 are more nearly the same for all plots, and represent to 

 a large degree the nitrification of the organic residues in 

 the soil. The losses from the plots receiving minerals 

 and varying amounts of ammonium salts (5, 6, and 7) 

 increase with each application of nitrogen : the losses 



Nitric Nitrogen in Drainage Water.— Lbs. per Acre. 



Plot. 



3 



5 

 6 



7 

 9 

 10 

 11 

 12 

 13 

 14 

 15 



Manuring, per Acre. 



Unmanured 



Minerals only 



Minerals + 200 lbs. Ammonium Salts 

 „ +400 „ „ 



>» +55° i) Nitrate of Soda 



400 lbs. Ammonium Salts alone 

 Do. do. + Superphosphate 



Do. do. 4-Sulph. Soda 



Do. do. 4-Sulph. Potash . 



Do. do. 4-Sulph. Mag. 



Minerals 4- 400 lbs. Ammonium Salts 

 in Autumn 



Estimated Drainage — inches 



from the plots receiving ammonia and various mineral 

 manures diminish as the mineral manure becomes a 

 more complete plant food, because the greater growth of 

 crop thus secured more completely removes the nitrates 

 as they are formed, besides hindering nitrification by 

 drying the surface soil. 



The effect on nitrification of crop and surface 

 cultivation is well seen in the following table of results 



