Optimal parameters of agrocenosis, habitat-forming factors and agrotechnologies for winter wheat planting in Samara region
In the conditions of climate changing the main element of sustainable grain production in the Samara region are winter crops planting. The researches on identifying the relationship between habitat-forming factors and agricultural technologies of cultivation on the yield of winter wheat were conducted in long-term field experiment of Soil Management Department at Samara Research Institute on Agriculture. Climatic conditions during the period of researchers (2000-2010) were within the perennial average parameters (hydrothermal coefficient for the period May-June - 0,67.1,88) and advocate to crop vegetation. In 2005, 2007-2010 гг. the drought conditions occurred in spring and summer periods (hydrothermal coefficient for the period May-June - 0,13.0,50). The use of technologies with minimal and differentiated soil tillage on ordinary black soil, in comparison with traditional, didn't aggravate agrophysical and agrochemical properties of the soil and did not reduce the crop yield. The research defined a significant direct relationship between the yield of winter wheat stalks and density (r = 0,73*...0,80**), height (r = 0,63 *.0,72 *) and weight of grain per plant (r = 0,61*.0,76**). Among abiotic factors the main influence on the yield of winter wheat in all variants was provided by the temperature of the air. The highest rates was in the critical phase of plants vegetation development - tillering and booting (r = -0,79 **.0,85 **). Use of varieties with high potential productivity, adaptability to modern technology, responsive to the intensification factors of production - Candle, Turquoise, Malachite ensured the formation of winter wheat yield at the level of 4,0...5,0 t <sup>-ha</sup> along with an increase in compensation for additional costs in 1,2 - 1,5 times in comparison with standard varieties (Mironovskaya 808, Bezenchukskaya 308). These investigations have established the optimal parameters of technology and environment-forming factors for enterprises in Samara region with different resource facilities with the aim of their adaptation to climatic conditions and stabilization of winter wheat grain production.