Biological factor of humus reproduction in conditions of the steppe zone of the Southern Urals

Abstract

The paper considers a biological factor affecting the reproduction of humus and the maintenance of soil fertility in a region with unstable moisture. In the steppe zone of the Southern Urals, the humus formation process is affected by the amount of plant (stubble-root) residues entering the soil, which suggests the possibility of reducing the mineral fertilizers use. The purpose of the experiment was to determine the affecting of a set of field crops in crop rotations on the input of organic matter into the soil of the southern chernozem. The paper studies three variants of the experiment with different types of fallow. An increase of humus in the soil by 0.17% (in the percentage) was found in the crop rotation with fallow occupied by the summer sowing of Sudanese grass in comparison with grain-fallow with weed-free fallow. On average over 10 years, the largest volume of organic matter entered the soil during the cultivation of winter rye in a crop rotation with weed free-fallow (11.87 tons per 1 ha).