482 FI£]Llj Chul-b 



Live-stock farming aids in conserving these elements, for 

 live-stock products remove much less of them than grains, 

 hay, and cotton. If the manure is pfroperly handled and 

 returned to the land, the exhaustion of the soil will be very 

 slow, but it will be constantly taking place. The products 

 which are sold will remove some of the potassium and phos- 



Figure 154. — Good plowing is essential to the production of good crops. 



phorus, while there will also be a considerable loss by leach- 

 ing from the soil and from the manure. Some phosphorus 

 and potassium should occasionally be added from outside 

 sources in the form of purchased feeds or of fertilizers in 

 order to maintain or to increase the fertility of the soil. 



WHAT A ROTATION SHOULD CONTAIN 



661. Classes of Crops in a Rotation. So far as their 

 arrangement in a rotation is concerned, field crops may be 

 divided into grass, grain, and intertilled, or "fallow,'* crops. 

 Grass crops include all the plants which are grown in meadows 

 and pastures, such as the perenaial forags gra«;;eftj clovers, 



