Soil Organic Carbon Stocks under No-Tillage in the Middle Volga Region

Abstract

The introduction of resource-saving technologies into the practice of agriculture is one of the approaches to preserving soil fertility and increasing the reserves of organic carbon (Сorg). One of such technologies is zero tillage, which has been actively used all over the world since the middle of the twentieth century. However, there is still insufficient information about the effectiveness of this technology for the accumulation and preservation of Сorg in the agro-soils of our country. The paper estimates the rate of accumulation of Сorg by agrochernozems with zero tillage in the conditions of the Middle Volga region. On the territory of agricultural farms (Pokhvistnevsky district of the Samara region), 2 agricultural fields with 5- and 8-year zero tillage (88 and 161 hа, respectively) and a field with non-fallow plowing (42 hа) were selected. 30 study points were selected in each field, from which soil samples of the upper (0–10 cm) and lower (10–30 cm) layers of humus-accumulative and partially illuvial horizons were selected. The paper presents the main physic-chemical parameters of the soil and calculated the reserves of Сorg. A significant increase in sorghum reserves in the upper soil layer was shown at 5- and 8-year zero tillage (on average by 0.57 and 0.45 kg/m2) compared with those during plowing, but no significant differences were found for the lower layer. The total sorghum reserves for the 0–30 cm soil layer at zero tillage increased by 0.61 and 0.34 kg/m2 relative to those during plowing. Consequently, as a result of the application of zero processing, the rate of accumulation of Сorg reserves in the agrochernozems of the Middle Volga region can reach 1.22 and 0.43 t/ha per year, which is 1.3–41 times more than the recommended program “4 ppm” for agricultural lands of our country (from 0.03 to 0.33 t/ha per year).