The influence of minimized tillage on grain crop productivity
The paper deals with the studying the possibility to reduce tillage ways in a stationary experiment on the gray forest rough-loamy soils of the Middle Urals. The experiment was carried out in 2007 in the system of grain-grass crop rotation and is currently undergoing the second five-year rotation. Instead of plowing as variants of minimizing the tillage with a heavy cultivator (15-16 cm) and disking (8-10 cm depth) being used, the replacement of plowing by heavy cultivating did not cause significant changes of the physical properties of the soil and the complete absence of tillage resulted in increased density during the following years up to 1.5 times. Deep autumn tillage compared with surface cultivation, or leaving the stubble favoured the increase of spring moisture reserves in the 0-50 cm layer up to 11-19 mm. The content of available nitrogen in the upper soil layer in the variant without autumn tillage declined by 9-23% in comparison with the loosening at the depth of 20 cm. This is due to the soil compaction which causes unfavorable conditions for nitrification. Clover application in the rotation process for green manure made it possible to neutralize the negative effects of zero tillage in autumn. In the first rotation the 2-times plowing per rotation, combined with resource-saving methods of tillage did not reduce crop yields and the crop rotation productivity in whole. With zero tillage in the yield of barley significantly decreases up to 0.3 t/ha. The overall positive economic effect of minimized tillage in grain-grass crop rotation is possible due to the following three components of the potential productivity: the use of protection means, the use of clover for green manure, applying for grain crops 30 kg/ha NPK. (30 кг д.в./га NPK)