RESULTS OF THE STUDY OF DIFFERENT TILLAGE SYSTEMS IN GRAIN-FALLOW CROP ROTATION ON CHERNOZEMS OF THE MIDDLE VOLGA REGION

Abstract

The studies were conducted at the Federal State Budgetary Scientific Institution of the Ulyanovsk Research Institute of Agriculture in 2011-2017, located in the forest-steppe zone with an annual rainfall of 360-500 mm. The soil of the experimental plot was represented by weakly leached heavy loamy chernozem with a humus content of 5,8%. The crops were placed in a grain-fallow rotation: bare fallow – winter wheat – spring wheat – peas – winter wheat – barley. We studied 4 tillage systems. The moldboard system included plowing for all crop rotation crops to a depth of 20-22 cm; the combined system of tillage at a variable depth covered subsurface surface tillage for winter crops, deep plowing under peas and subsurface tillage to a depth of 20-22 cm for other crops; surface tillage by 10-12 cm and zero tillage for all crop rotation crops. The arable soil layer was characterized by favorable agrophysical properties, which were practically independent on the tillage systems: so, the lumpy-granular macrostructure with aggregate size from 0,25 to 10 mm was 75,2% for plowing, 75,6-76,5% for non-cultivating variants. On all tillage systems, the soil density corresponded to the optimal value for the growth and development of cultivated plants (1,22-1,25 g/cm³). The number of water-resistant units with a diameter greater than 0,25 mm was high and did not fall below 76%. On the zero, surface and combined cultivations, the average crop rotation content of the productive moisture was 115,3; 119,1 and 121,5 mm, which was at the control level of 115,4 mm. A larger grain harvest from 1 hectare of crop rotation area was provided by the combined tillage system (2,71 tons). When moldboard, minimal and zero tillage, we yielded, respectively, 2,65; 2,62 and 2,56 tons/hectare.