Crop rotation in relation to the agriculture of the corn belt

The same basic principles of crop rotation apply in the corn belt as on other soils in other localities. Alternation of crops, including legumes at frequent intervals, is fundamental to the maintenance of a profitable agriculture. Continuous corn or corn and other grain growing, with little return of plant food in manure or fertilizer, has greatly reduced the fertility of the soil on many if not most corn belt farms. The most important losses in fertility have occurred in the reduction of the effective organic matter and nitrogen content of the soil. These constituents are especially important because the production of corn, the most important crop, uses them up in large amounts. Corn is the principle crop of the corn belt and must be recognized as such and provided for in any systems of crop rotation proposed for general use in this region. The large proportion of corn demanded by the farmer makes the arrangement of rotations that will satisfactorily maintain soil fertility unusually difficult. The greatest problem in the agriculture of the corn belt, so far as crop production is concerned, is the maintenance of adequate supplies of organic matter and nitrogen in the soil. The climatic conditions of this region are highly favorable to rapid decomposition and nitrification and the tillage operations required in corn culture greatly enhance these processes. To meet the heavy requirements of organic matter and nitrogen, crop rotations must be so arranged and managed as to bring in the rank-growing legumes as frequently as possible, either as full crops or as inter-crops, while at the same time maintaining a large proportion of corn in the cropping system. To do this satisfactorily, the acid soils must be limed and manures and fertilizers, especially phosphate, must be utilized much more extensively.