204 



Agricultural Chemistry. 



lie compared a virgin soil of that province with one that had 

 been continuously cultivated to cereal grains or fallow for 20 

 years. The cultivated soil contained 0.253 per cent of nitrogen 

 (to a depth of 8 inches) and the virgin soil contained 0.371 per 

 cent. This difference represented a loss of 2200 pounds of nitro- 

 gen per acre by the system of cultivation practiced. Investi- 

 gating the possibility of restoring nitrogen to the soil, Shutt grew 

 common red clover upon a poor sandy soil, cutting the crop twice 

 yearly and leaving it upon the soil. At the end of each second 

 season the crop was turned in and the plot re-sown the next 

 spring. In five years of this treatment the soil gained over 300 

 pounds of nitrogen per acre to a depth of four inches, despite 

 inevitable losses by nitrification and leaching. 



The effect of the growth of clover on succeeding crops was 

 demonstrated by Shutt in field experiments. Two series of plots 

 were used, on one of which clover was compared with wheat, 

 while on the other oats and clover were compared with oate. 

 The first series will be described. On one plot, clover was sown 

 alone and one cutting made and removed. The crop was turned 

 under in the following spring. On the other plot, wheat was 

 grown and harvested as usual. The effect of this treatment was 

 observed on grain and root crops for three succeeding years, with 

 the following resultant data: 



Increase of Crop Due to Growth of Clover. 



