DRY-FARMING 



districts in the West, notably in Oregon 

 and in Minnesota, where the continuous 

 cropping of wheat over periods of ten to 

 thirty years has seriously injured the 

 land. The only rational way of restoring 

 the fertility to such soils and increasing 

 the yields on these old grain lands is by 

 rotation of crops, and the use of barn- 

 yard and green manures so as to return 

 vegetable matter to the soil. One of the 

 very best crops to use for this purpose is 

 clover which has given such excellent re- 

 sults on the exhausted wheat soils of the 

 Red River Valley and southwestern 

 Minnesota. Clover is a nitrogen-gath- 

 ering crop and is unrivaled as a soil- 

 renovator. In dry-farming, commercial 

 fertilizers are of little practical use and 

 should be avoided. For they do not in- 

 crease the store of humus — vegetable 

 mold — which is so important an agent in 

 conserving the soil moisture. Further- 

 50 



