164 



AGRICULTURE FOR BEGINNERS 



by good tillage, and by a thorough system of crop rotation. 

 Cowpeas make a most valuable crop to precede wheat, for 

 in growing they add atmospheric nitrogen to the soil ; their 

 roots loosen the root bed, thereby admitting a free circula- 

 tion of air, and adding humus to the soil. Moreover, the 



cowpea leaves the soil 



in the compact condition 

 so much desired in wheat 

 production. 



One may secure a good 

 seed bed after cotton 

 and corn as well as after 

 peas. They are summer- 

 cultivated crops, and the 

 clean culture that has 

 been given them renders 

 the surface soil mellow 

 and the undersoil firm 

 and compact. They are 

 not so good, however, as 

 cowpeas, since they add 

 no atmospheric nitrogen 

 to the soil, as all leguminous crops do. 



From one to two inches is the most satisfactory depth for 

 planting wheat. The largest number of seeds comes up 

 when planted at this depth. A mellow soil is very helpful 

 to good coming up and provides a most comfortable home 

 for the roots of the plant. A compact soil below makes a 

 moist undersoil; and this is desirable, for the soil water is 

 needed to dissolve plant food and to carry it up through 

 the plant, where it is used in building tissue. 



FIG. 154. ROOTS OF A SINGLE 

 WHEAT PLANT 



