250 



SOIL PHYSICS AND MANAGEMENT 



The results show that fallowing gives considerable increase over 

 continuous cropping. The longer this is continued the greater the 

 difference. Whether alternating crops with summer tillage is 

 profitable will be determined largely by local soil and climatic con- 

 ditions that influence the cost of production. 



Summer Tillage With Alternate Cropping vs. Continuous Cropping* Noith 

 Dakota Station (Bushels Per Acre) 



*Pounds. 



It will be seen from this table that summer tillage gave an 

 increase for wheat, oats and barley, but best results were obtained 

 for corn by continuous cropping. 



Crops for Dry Farming. In no kind of agriculture is the 

 adaptation of the crop to the environment of greater consequence 

 than in dry farming. In general, the crops should be sut'h that 

 a maximum growth is secured with minimum water requirements, 

 and the crops that meet this condition will be best adapted to 

 dry-land agriculture. Alfalfa is an exception, but its deep-root- 

 ing character has fitted it for securing a large amount of water. 

 Most crops have the power of adapting themselves to some extent to 

 the conditions of climate after a few years, but the dry-land farmer 

 needs a variety of crops that have been tried and developed by 

 selection so that they resist the unusual conditions to which they 

 are subjected. Upon the selection of the crop and seed may depend 

 the success or failure of his efforts. 



(a) Wheat is the principal crop for the dry-land farmer. All 

 over the arid and semi-arid regions wheat has proved to be one of 

 the best drouth -resistant crops that can be grown. In the dry-land 

 regions of other continents wheat has been grown for many cen- 

 turies, and certain varieties have been developed which are welt 



