Control of the humus supply of certain important Missouri soils

Abstract

The soils of Missouri, with very few exceptions, are deficient in humus, and the continuous cropping (to corn especially) which is practiced in many parts of the state is rapidly depleting what humus there is in the soil. In many parts of the state the crop yields are rapidly decreasing as a result of this, while in other localities it is not as yet evidenced in the crop yields to a perceptible degree, but in either case it demands attention, for it is much easier to maintain a natural humus supply than it is to build one up, and in the case of the lands where it is now effecting the crop yield it must be built up or the land will soon fail to produce a remunerative crop. In order to study the effect of various crop rotations and fertilizer treatments upon the humus content of Missouri soils two lines of experiment were carried out. First, a study of the effect of crop rotation and manures upon the humus and nitrogen content of soils as evidenced in the rotation plats of the Missouri Experiment Station. And second, a study of the needs of organic matter of some of the more important soils of the state by means of the paraffine wire basket method.