The Soil: Its Use and Abuse 



^3^5 



PRACTICES AVAILABLE FOR SOIL IMPROVEMENT 



We see, then, that by drainage, irrigation, tillage, manures, and fer- 

 tilizers (including lime), the farmer endeavors to modify the soil. To 

 these he may and should add two other practices essential to the highest 

 financial results. These are crop rotation and crop adaptation. 



a. Crop rotation. — Nature rotates her crops, and there must therefore 

 be a fundamental reason for the practice. In the forest, oak follows pine 

 and pine may follow oak. On the farm, corn after com and wheat after 





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Fig. 13. 



-Potatoes grow best on a fine sandy toam soil. Both the yield and the quality are 



best on this kind of soil 



wheat soon results in small crops, whereas a succession of crops, properly 

 adjusted, gives a larger total production. It is evident, therefore, that 

 there is created by a one-crop system some soil condition not conducive 

 to the best results. A succession of different crops periodically repeated 

 gives better results: it gives better yields, in the first place; it keeps the 

 soil in better physical and chemical condition; it conserves food, keeps 

 down weeds, reduces disease and insect attacks, and incidentally, although 

 not necessarily, saves labor. A good crop rotation is recognized as an 

 essential part of a good system of crop production. 



Many systems of rotation have been devised. They must be adapted 

 to the soil and to the market conditions, or to the type of farming followed. 



