Effect of Tillage Systems on the Density of Typical Chernozem in the Trans-Volga Region
Under conditions of the steppe trans-Volga region in 1975-2010 the investigations were carried out in order to determine the influence of tillage methods, a modern technological system of tillage and crops of field cultures with biological methods of reproduction of soil fertility on the density of typical chernozem and its correlation with the productivity of cultures studied. Long-term use of various tillage methods, technological systems for soil cultivation and field crops sowing does not lead to over-compaction of typical chernozem. The density of the arable layer of the soil during the growing season was within the optimal values for the cultivation of field crops in the region (1.0-1.3 g/cm3). Its values in spring were the most dependent on spring precipitation: r = 0.30-0.61* (spring cereals) and air temperature in September-April: r = 0.41-0.69* (winter wheat). The use of direct sowing of spring cereals (1999-2010) with the biological methods of reproduction of soil fertility (straw, crop residues) ensured more rational decomposition of organic materials and soil decompaction compared with other options by 0.02-0.05 g/cm3 (1.9-4.9 %) during the spring period. The density of the soil was differentiated in layers. In the variants with the main tillage the most compacted layer was 20-30 cm (1.09-1.16 g/cm3). In direct sowing the density in the layers 10-20 and 20-30 cm was 1.07-1.08 g/cm3, which indicates the decompaction in the untreated layers and the possibility of using technological systems, including direct sowing, without deterioration of agrophysical properties of typical chernozem in the steppe trans-Volga region and without the decrease in the yield of the main field crops.