50 



Samples collected at the same date from the unmanured alternate 

 wheat and fallow plots showed to the same depth : — 



lbs. 



After fallow 33-7 



After wheat 2 G 



Diifercnce 31 '1 



Lastly, two fields which had been manured and cropped in the 



ordinary course of the farm, and had been fallowed since the previous 



autumn, showed, according to determinations in samples collected in 



October 1881, the following amounts of nitrogen as nitric acid per 



acre to the depth of 27 inches : — 



lbs. 



Claycroft field 58-8 



Foster's field 5G '5 



Thus there was very much less nitrogen as nitric acid found in the 

 soils to the depths examined, after the growth of the leguminous crop 

 beans, as well '^er that of the gramineous crop wheat, than in the 

 correspond' .w soils; indicating, therefore, a like source of 



some, r ' . jc;, of the nitrogen of both crops. 



It oe seen, however, that even in the cases of the soils 



receiving nitrogenous manure, the amuunt of nitric acid found to the 

 depths examined, is very far from sufficient to account for so large 

 an accumulation in the crop, and in the surface soil, as the figures 

 relating to the nitrogen in the produce of the clover, and in the clover 

 and barley soils, would indicate had been accumulated. 



The amounts of nitric acid formed, or remaining, within a limited 

 depth from the surface, at any one time, is, it is true, as already 

 intimated, dependent on so many temporary circumstances, that it is 



* The manures are applied every fourth year, for the root-crop commencing 

 each course of — roots, bp- ^ey, leguminous crop or fallow, and wheat. 



