ROTATION OF CROPS 269 



nance of fertility and to the production of maximum and 

 profitable crops. 



It is Nature's plan : she favors giving crops fresh lands 

 to grow in. Note the forest: when trees are cut, new and 

 different kinds grow in place of those removed. Note the 

 grass : timothy and clover may grow abundantly, but in 

 the end Bermuda (in the South) and blue grass drive both 

 away. Note the cultivated crop : corn does better after 

 clover or alfalfa, wheat after corn or potatoes, cotton after 

 cow peas or grass, than either crop after its own kind. 



A soil is severely injured when a cultivated crop like 

 corn or cotton is grown on it year after year. Even wheat 

 or oats, timothy or cow peas (when cultivated) bring 

 about the same ill-effect. The humus is burned out, the 

 soil hardens and deadens, the elements of plant food, 

 especially needed for these special crops, become scant. 

 Hence, the soil loses its power to successfully produce 

 the constant crop. You can correct this trouble, to a great 

 extent, by a change of crops. 



A few principles that enter into the scheme of crop 

 succession are : 



Plants place their roots differently in the soil. 



All plants exhaust the soil. 



Plants do not exhaust the soil in the same manner. 



All plants do not exhaust the soil equally. 



Some plants add nitrogen to the soil. 



Some plants act favorably to weed growth while others 

 do not. 



Plants, grown constantly on the same land, favor the 

 spread of insects and diseases. 



Feeding habits of the crop. It is well to pay attention 

 to the feeding habits of a crop. The shallow feeder ought 

 not to follow a crop having a similar nature : it ought to 

 follow a crop whose roots penetrate deeply into the 



