Productivity of crop rotations on lignt chestnut soils of the Lover Volga region

Abstract

Recently the orientation on fertilizers of agrogenous origin (leies, straw, crop residue) is significantly expanding. As the main agricultural instrument, ensuring the achievement of these goals, scientifically based crop rotation is adopted as a method for regulating the receipt and quality of organic matter into the soil and the speed of its transformation. In this regard, our research is aimed at developing the optimal structure of field and crop rotations for a developing situation. The cultivation technology of crops was generally accepted for the research area. Placing options were: (A) sequential and (B) blocks in three tiers. The main soil cultivation in the experiment was beardless plowing by stilt SibPME to a depth of 25–27 cm. Regionalized varieties of agricultural crops were cultivated. The counts and observations were carried out according to the recommendations. For the period July — August, the largest amount of precipitation fell in 2016 — 119.0 mm; the smallest in 2017 — 6.0 mm, in other years this indicator was in the range of 32.8–86.0 mm. On average, over the years of research, the greatest accumulation of crop residues, straw and roots was in a 4-field crop rotation with black fallow — 3.4 t/ha. The highest amount of nitrogen entering the soil with straw, crop residues was noted in an 8-field crop rotation — 49.8 kg/ha. The largest amount of biological nitrogen (according to Trepachev’s method) was accumulated under alfalfa crops — 34.4 kg/ha. Analysis of soil samples for the content of humus over the years of research did not reveal significant changes. The best predecessor for winter wheat is black fallow. After perennial grasses, peas, the grain yield of winter wheat in some years decreases by 4–12 c/ha. Analysis of the correlation dependence of the productivity of crop rotations has shown that the highest dependence with atmospheric precipitation for May — June is t = +0.50 for grain and fodder units and slightly less — for protein (t = + 0.26–0.50).