THE DEVELOPMENT OF DRY FARMING 9 



excessive evaporation or periods of drought or other 

 cause results in moisture becoming the limiting factor. 



The precipitation zones of Western Canada are indi- 

 cated in the following chapter. The boundaries of 

 these are based upon the limited rainfall and snowfall 

 data available. They will, no doubt, be modified and 

 more accurately located as more records beaome avail- 

 able, but in the meantime they furnish us with the ap- 

 proximate boundaries of the precipitation zones. 



The areas of different evaporation cannot be mapped 

 owing to lack of data. The Chinook region, is, how- 

 ever, generally believed to have the greatest evapora- 

 tion, and the northeastern portion of the Prairie Pro- 

 vinces to have the least.^ 



Judging from the precipitation records and the data 

 for spring and fall frosts as well as from the costly ex- 

 periences of farmers, it would appear that wliile several 

 of the practices of dry farming should be applied wher- 

 ever land is tilled, the extreme practices of this system 

 should be applied in Western Canada only in the 

 Chinook belt, in a modified form they should be used 

 in the prairie area outside the Chinook belt, while in a 

 still more modified form they may be used in eastern 

 Manitoba, the park belt and the wooded areas. (See 

 "Nature's Map of the Prairie Provinces"). 



It should perhaps be emphasized here that in grow- 

 ing grain crops in places where fall frosts are more to 

 be feared than drought, less attention should be given to 

 moisture storage and more to getting crops ripe. Both 

 moisture conservation and early maturity may be de- 

 sirable but where added moisture results in too late 

 ripening it must be sacrificed in areas where crops are 

 grown for their seeds. If forage crops only are to be 



