The proper time to begin the cultivation of corn is before it is planted. Plow well. A shallow, worn-out soil should not be used for corn, but for cowpeas or rye. After thorough plowing, the harrow--either the disk or spring-tooth--should be used to destroy all clods and leave the surface mellow and fine. The best results will be obtained by turning under a clover sod that has been manured from the savings of the barnyard. When manure is not available, commercial fertilizers will often prove profitable on poor lands. Careful trials will best determine how much fertilizer to an acre is necessary, and what kinds are to be used. A little study and experimenting on the farmer's part will soon enable him to find out both the kind and the amount of fertilizer that is best suited to his land. The seed for this crop should be selected according to the plan suggested in Section XIX. [Illustration: FIG. 199. CORN SHOCKED FOR THE SHREDDER] The most economical method of planting is by means of the horse planter, which, according to its adjustment, plants regularly in hills or in drills. A few days after planting, the cornfield should be harrowed with a fine-tooth harrow to loosen the top soil and to kill the grass and the weed seeds that are germinating at the surface. When the corn plants are from a half inch to an inch high, the harrow may again be used. A little work before the weeds sprout will save many days of labor during the rest of the season, and increase the yield. [Illustration: FIG. 200. THE DIFFERENCE IS DUE TO TILLAGE] Corn is a crop that needs constant cultivation, and during the growing season the soil should be stirred at least four times. This cultivation is for three reasons: 1. To destroy weeds that would take plant food and water. 2. To provide a mulch of dry soil so as to prevent the evaporation of moisture. The action of this mulch has already been explained. 3. Because "tillage is manure." Constant stirring of the soil allows the air to circulate in it, provides a more effective mulch, and helps to change unavailable plant food into the form that plants use. Deep culture of corn is not advisable. The roots in their early stages of growth are shallow feeders and spread widely only a few inches below the surface. The cultivation that destroys or disturbs the roots injures the plants and lessens the yield. We cultivate because of the three reasons given above, and not to stir the soil about the roots or to loosen it there. [Illustration: FIG. 201.]