CORN CULTURE. The profitable pro duction of corn depends upon: (1) fertility of soil; (2) conditions of climate; (3) quality of seed; (4) methods of cultivation.
Fertility of soil is the first and most im portant of these conditions. Three elements, nitrogen, phosphorus and potassium, are im portant constituents of soil fertility, and the ones which are frequently lacking in quantity in the soil's composition, or become quickly exhausted by continuous cropping without prop er rotation of crops or application of manures. In those regions where corn is most extensively grown, as in the Mississippi Valley of the United States, the fertility of the virgin soils seemed almost unlimited to the pioneer farmers, who in many instances grew crop after crop of corn, selling the product off the land without apparently diminishing the productiveness of the soil. However, after a half century of such practice, it has been found that the soil has been exhausted by this system of farming. The depleted soils are found to have an insufficient supply of the important elements necessary to render them fertile, and it has become neces sary to resupply them directly in the form of commercial fertilizers, or indirectly, through the use of barnyard or other like manures, or by the growing of green manure crops.
Methods of Restoring or Maintaining the There are several methods which are practised with economical results in the corn belt of restoring exhausted corn lands to a fertile condition, and of keeping up the fer tility of such soil under cultivation. It will be impossible to treat of many of them in detail here, so that only a few of the principal plans will be outlined.
Commercial The use of com mercial fertilizers for corn land is limited to those soils which are lacking in one or more constituents of plant food which can be bought in the market, either alone or in combination, at a reasonable cost, usually, nitrogen, phos phorus, potassium or lime. Their general use is limited from the fact that the cost of supply ing plant food in this way is so great that the returns in crops like corn do not usually justify the outlay. Nitrogen, phosphorus and potas
sium now bring a high price per pound, when purchased in artificial fertilizers. From the fact that a large quantity of these constituents are removed in a crop of corn it can be seen that it would be unprofitable to use them for the growing of a crop without having as a basis a soil naturally sufficiently supplied with one or more of these elements. In some cases it may be advisable to apply one or more of these constituents to correct some unusual soil con dition, but the large areas which are naturally rich in all necessary elements of plant food for corn, and adapted in all conditions for growing corn, preclude their general use for this pur pose by the corn growers of the United States.
Barnyard Barnyard manure con tains a large supply of plant food, and when applied to the soil not only increases its fer tility but improves the mechanical condition, or tilth, as well. The large amount of straw and vegetable matter in its composition, when de composed and assimilated by the soil, improves its condition for corn crops. In fact it has come to be a generally followed practice among our most progressive farmers to feed the corn crop to five stock, carefully conserving the manure for application to the soil. In such cases, the best plan seems to be to compost the manure, and after it has become well-rotted, to spread it on the field while the soil is frozen in winter, plowing it under to a good depth in the spring. This practice can be followed only where local conditions permit. On soils that leach or are carried off by rains it is necessary to apply the manure at the times when it will not be washed off the soil by winter or spring rains, or wasted from other causes. In such cases, the manure may be spread on grass lands or pastures in the spring or summer, the field being plowed for corn the following autumn or spring. About 10 tons of well-rotted manure per acre is considered a sufficient application for ordinary corn land.