62 DRY FARMING 



organic matter are supplied by manure and crop resi- 

 dues (including legumes used as green manure, etc.). 

 Commercial nitrogen, such as sodium nitrate, does 

 not pay under extensive systems of farming. When the 

 land is acid (sour) ground natural limestone, made from 

 crushing limestone found in natural deposits, is most 

 effectual and economical. To supply phosphorus, finely 

 ground, natural raw rock phosphate is applied, being 

 the cheapest form, and, under humid conditions when 

 applied with actively decaying organic matter, being as 

 effective as the more readily available but more expensive 

 acid phosphate. 



The practices of the more humid Corn Belt will not 

 apply in full to Western Canadian conditions. Under 

 semi-arid conditions, our soils cannot handle the amounts 

 of crop residues or manure that are turned under in the 

 humid regions. However, with the depletion of organic 

 matter and nitrogen our system must be changed. Mixed 

 farming is undoubtedly becoming more general and the 

 manure should be carefully conserved. But this will 

 never entirely supply the soil needs for organic matter 

 and nitrogen. The use of leguminous crops in the rota- 

 tion will be a big step in advance. 



It is interesting to note in the Illinois Experiment 

 that where the needs of the soil are fully 'provided for 

 (plots 6 and 7) the grain system is equal, if not slightly 

 superior, to the live stock system of farming. Thus, it 

 is possible in the Corn Belt to farm entirely without 

 live stock. The Canadian prairies may always be de- 

 voted chiefly to grain farming, and if our agriculture is 

 to be permanent and profitable, we must plan our sys- 

 tems for conditions as they actually exist. Only by long- 

 continued, carefully conducted experiments such as the 



