CHAPTER XIV 

 THE CAUSES AND CONTROL OF LOW YIELDS 



197. The Causes of Low Yields. — The major causes of 

 low yields in the West at the present time are climatic — 

 drought, frost and high winds. The many minor causes 

 are the cropping and soil management practices man em- 

 ploys or fails to employ — in the operation of his farm. 



In the final analysis all low yields trace back to one 

 or more of six fundamental things : — 



1. The purity or quality of the seed. 



2. The suitahility of the crop or the variety. 



3. The supply and availability of the plant food in 

 the soil. 



4. The moisture in the soil. 



5. The temperature of the soil and air. 



6. The amount of air in the soil. 



But while this list includes the immediate or funda- 

 mental causes of low yields, yet each of these is the direct 

 result of certain other influences or practices to which is 

 generally ascribed the cause of the decreased return. 

 The former may be regarded as the immediate or funda- 

 mental causes, the latter as the practical causes of partial 

 or complete failure. 



The fundamental cause of low yield in a certain field 

 may be lack of moisture. The practical cause may have 

 been, poor fallowing, weeds, warm winds, low precipita- 



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