CHAPTER XI 



RELATION OF TYPE OF FARMING TO SOIL FERTILITY 



The increase of stock and the improvement of the land are two events 

 that must go hand in hand, and of which the one can nowhere much outrun 

 the other. ADAM SMITH in "Wealth of Nations" 



142. Returning the fertility removed in crops. No system 

 of agriculture is permanent that does not return to the soil 

 as much plant food as is removed by the crops grown. From 

 the results of the experiments conducted by the Illinois and 

 Missouri experiment stations it was seen that under a good 

 cropping system the productiveness of the land was main- 

 tained on a much higher plane than where corn was grown 

 continuously. The experiments also showed that where manure 

 was added to the rotation, much larger yields were obtained. 



Crop rotation, then, is only one of the steps necessary in 

 maintaining the productiveness of soils ; and the proper use of 

 manures or fertilizers is just as important. It is true that if the 

 supply of organic matter and nitrogen is maintained by green 

 manures and by crop residues, it will require many years for 

 good soils to show a material decrease in fertility. But in the 

 end any system of farming that does not provide for the return 

 to the soil of as much plant food as is removed by the crops 

 will deplete the fertility of the soil. 



143. Feeding the crops to live stock. One very practical way 

 of returning to the soil a large part of the plant food removed 

 in the crops is to feed the crops to live stock, taking care that 



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