THE SOIL 



61 



for hay in both systems The residues from grain 



and legume crops may be plowed under directly, or they 



Fig. 22. — Illinois Soil Experiment. 

 Farm manure and rock phosphate applied. Average yield 51.8 bushels per 

 acre. P)iosphorus increased the yield 17.6 bushels per acre. The lessons 

 tanght are being put into practice by Illinois farmers. Figures 21 and 22 

 illustrate the result of scientific investigation, and though it should 

 not be inferred that these results will accrue from the same treatment in 

 Western Canada, the need for work of a similar nature is apparent. 

 — Courtesy Illinois Experiment Station. 



may be used as a top-dressing for the protection of winter 

 •crops and eventually turned under." 



The methods of soil enrichment illustrated by this ex- 

 periment have come into common practice in Illinois and 

 several of the adjoining states. Thus nitrogen and 



