THE CHEMICAL COMPOSITION OF SOILS 



soil. Where the crops are systematically rotated, live 

 stock is kept, and the manure judiciously used, the 

 crop-producing power of the land is not lowered, as in 

 the case of the one-crop system. The influence of dif- 

 ferent systems of farming upon the humus content and 

 other properties of the soil may be observed in the fol- 

 lowing table : 31 



