ROTATION OF CROPS 485 



destroying them are limited. Some classes of weeds increase 

 in meadows and pastures. An intertilled crop is needed at 

 intervals to subdue weeds and to keep them from over- 

 running the land. Tillage aids in retaining the soil moisture 

 and in liberating supplies of plant food. Stirring the soil 

 allows the air to penetrate to the roots of the plants and 

 enables them to grow better than in hard, cloddy ground. 

 The aeration of the soil also improves its texture and pro- 

 vides more favorable conditions for the growth and work of 

 some of the beneficial bacteria. 



664. A Crop for Cash Returns. It is essential, if the 

 work of the farm is to be made profitable, that at least one 

 crop be grown for cash returns. It need not necessarily be 

 one which is sold in its natural state, for it may be converted 

 on the farm into animal products and then marketed. On 

 many farms, however, some crop is grown for direct sales 

 for cash or its equivalent. If no cash crop is grown, there 

 is no opportunity to increase the available funds for neces- 

 sary improvements or for the purchase of food and clothing 

 and other necessities of life which cannot be produced on 

 the farm. It might be possible to follow a rotation of crops 

 which would rapidly increase the available supply of plant 

 food by growing only such crops as clover, rye, and cowpeas 

 and continually plowing them under as green manure crops, 

 but this practice would yield no cash returns and could be 

 followed only where there was some source of income from 

 outside the farm. In general, the growing of a cash crop is 

 a necessity. Cotton, wheat, potatoes, tobacco, flax, barley, 

 and sugar beets are important crops which are grown for 

 direct sales. Hay and corn frequently become cash crops 

 indirectly by marketing them through live stock. 



665. A Crop for Feeding to Live Stock. At least one 

 crop should be included in the rotation which can be used 

 for feeding to live stock. The necessary work stock sliouid 

 be fed, as far as possible, on products grown on the farm, 



