THE MAINTENANCE OF SOIL FERTILITY 557 

 Table CXXIX 



ESTIMATED ADDITIONS THAT MIGHT OCCUR TO A SOIL UNDER A 



ROTATION OF MAIZE, OATS, WHEAT, AND TWO YEARS HAY. 



EXPRESSED IN POUNDS TO THE ACRE A YEAR. 



use of farm manure and a green-manure on the soil in question. 

 The green-manure is leguminous and is applied once during 

 the five-year rotation. 



Table CXXX 



FURTHER ADDITIONS THAT MIGHT BE MADE TO THE FIVE-YEAR 



ROTATION ON DUNKIRK SILTY CLAY LOAM, EXPRESSED IN 



POUNDS TO THE ACRE A YEAR. 



1 Important because of the additions of organic matter that occurs 

 thereby. 



2 It is estimated that of the crops removed and fed or used as bedding, 

 only 30 per cent, of the N, K 2 0, CaO and S0 3 , 50 per cent, of the P 2 5 

 and 25 per cent, of the organic matter reach the soil as farm manure (par. 

 294). The crops removed carried about 4000 pounds of organic matter 

 to the acre. 



3 The green-manure is estimated as 4000 pounds of air-dry matter 

 carrying 100 pounds of nitrogen, which is considered as fixed from the 

 air, This should yield 3000 pounds of soil organic matter. 



