THE ROTATION OF CROPS 



223 



the year and there is no crop on the land to check 

 loss of plant food from leaching and surface wash 

 during the winter. 



Because it is a weak feeder of phosphoric acid, 

 and can use only that which is in the most available 

 form. In applying fertilizer to cotton it is neces- 

 sary for best results to apply at least twice as much 

 phosphoric acid as the crop can use, because it can 

 use only that which is in the most available form 

 and the remainder is left in the soil unused. 



Continuous cotton culture then has an injurious 

 effect on all the important soil conditions necessary 

 to its best growth and development, and the result 

 is a diminishing yield or an increasing cost in main- 

 taining fertility by the use of fertilizer. 



How does continuous cotton culture affect the 

 economics of the farm? 



The injury to the soil conditions necessary to root 

 growth diminishes the yield and therefore increases 

 the cost of production. 



The poor soil conditions tend not only to dimin- 

 ish yield but also to diminish the quality of the 

 crop, which tends to lower the price received for the 

 cotton. 



Keeping the land constantly in cotton tends to in- 

 crease the insect enemies and the diseases of the 

 crop. 



The continuous, growing of cotton does not per- 

 mit the constant employment of one set of laborers 

 throughout the year. 



The continuous growing of cotton generally 



