ROTATION OF CROPS 243 



crops. Cabbage removes from the soil more water 

 than many other crops. With a good rotation it is 

 possible to earn' the water balance in the soil from 

 year to year, so that crops will be supplied in times of 

 drought. 



315. Rotation and Farm Labor. — The rotation of 

 crops should be planned so that an even distribution 

 of farm labor is secured. The importance of this 

 principle is so plain that its discussion is unnecessary. 

 It is a topic outside of the domain of chemistry, 

 but is nevertheless one of the most important to con- 

 sider in economic farming, and should not be lost 

 sight of in planning rotations. 



316. Economic Use of Manures. — Farm manure 

 should be applied to those crops which experience has 

 shown to be the most benefited by its use. At least 

 once during a five years' rotation the land should receive 

 a dressing of stable manure. If commercial fertilizers 

 are used, they should be applied to the crops which 

 require the most help in obtaining food. With the 

 growing of clover and the use of farm manures, only 

 the poorer kinds of soil will require commercial fertil- 

 izers for general crop production. It is more econom- 

 ical to reenforce the farm manures with fertilizers 

 especially adapted to the soil and crop than to purchase 

 complete fertilizers. 



317. Salable Crops. — In all farming, something 

 must be sold from the farm. It should be the aim to 



