in such a manner that the subsoil always contains sufficient moisture 

 seldom fail to produce good corn crops. The greater portion of the 

 corn-growing area, however, is dependent directly upon the rainfall 

 for its water supply, and it is for this reason that the absorption and 

 retention of water are so important. 



After the soil and subsoil have become well supplied with mois- 

 ture by the rains of fall, winter, and spring, the next important con- 

 sideration is the means by which it can be retained in the soil con- 

 stantly within reach of the growing crop. The effect of sunshine and 

 wind is to cause the moisture to pass rapidly from the soil directly 

 into the atmosphere, and unless cultural methods are employed to 

 lessen evaporation much of the soil moisture will pass into the air 

 without benefiting the crop except in a very slight and indirect way. 

 For the good of the crop as much of the soil moisture as possible 

 should pass into the atmosphere through the plants. In this way it 

 will carry the soluble plant food into the plants, whereas if allowed to 

 evaporate from the surface of the soil it will leave the soluble plant 

 food deposited on or near the surface, where it will be inaccessible to 

 the roots until it is cultivated deeper into the soil or washed there by 

 succeeding rains. 



As the moisture from the surface evaporates it is replaced by 

 moisture drawn from greater depths by capillary attraction, just as 

 oil is drawn through the wick of a lamp to replace that which is con- 

 sumed by the flame. The rapidity with wnich moisture will evapo- 

 rate from the ground depends upon the condition of the capillary 

 tubes or pores that connect the surface with the deeper soil. Any dry 

 'blanket that can be placed between the atmosphere and the damp soil 

 will check this evaporation. The most practical protection is a cover- 

 ing of finely pulverized dry soil 2 or 3 inches deep. By thoroughly 

 loosening the surface layer the soil particles are disarranged so that 

 the capillary tubes are not continuous. In this condition the surface 

 soil becomes quite dry and remains so without absorbing moisture 

 from below, thus acting as a mulch and retaining the moisture within 

 reach of the plant roots. It is necessary that this soil mulch be fine, 

 for if it is composed of clods air circulates between them and causes 

 evaporation to take place from the soil below the surface. A rain, 

 however, will wet the surface, causing the soil to run together and 

 crust, thus restoring capillarity. This makes another cultivation 

 necessary in order to renew the blanket of fine, loose soil. 



Fertilizers and Crop Rotation. A soil lacking in fertility can 

 be made to produce a crop of corn if the requisite amount of nitrogen, 

 potassium, and phosphorus be added and the soil kept in a good 

 physical condition; but the growing of corn on very poor land is 

 usually attended with very little or no profit. It is usually preferable 

 to buy corn rather than to raise it on impoverished soil. 



An application of commercial fertilizer may cause a soil to pro- 

 duce one good crop of legumes or other plants, and the roots and 

 foliage of this crop will usually benefit the physical condition and 

 fertility of the soil sufficiently to make other good crops possible 

 without additional applications of fertilizer. The practice to be 



