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.
Fig. 201.
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.
In many parts of the country the cornstalks are left standing in the fields or are burned. This is a great mistake, for the stalks are worth a good deal for feeding horses, cattle, and sheep. These stalks may always be saved by the use of the husker and shredder. Corn after being matured and cut can be put in shocks and left thus until dry enough to run through the husker and shredder. This machine separates the corn from the stalk and husks it. At the same time it shreds tops, leaves, and butts into a food that is both nutritious and palatable to stock. For the amount that animals will eat, almost as much feeding value is obtained from corn stover treated in this way as from timothy hay. The practice of not using the stalks is wasteful and is fast being abandoned. The only reason that so much good food is being left to decay in the field is because so many people have not fully learned the feeding value of the stover.
EXERCISE
To show the effect of cultivation on the yield of corn, let the pupils lay off five plats in some convenient field. Each plat need consist of only two rows about twenty feet long. Treat each plat as follows:
Plat 1. No cultivation: let weeds grow.
Plat 2. Mulch with straw.