Influence of agrometeorological conditions growing season and overwintering plants on yield of winter whead in central part of Republic of Mordovia

The results of forty years of paired observations in the central part of the Republic of Mordovia on the impact of agro-meteorological parameters (precipitation, hydro-thermic factor of the growing season, the depth of soil freezing, snow cover) on the yield of winter wheat (Triticum aestivum L.) of Mironovskaya 808 breed. Research has shown that, under conditions of almost unchanging farming techniques, significant fluctuations in the productivity of wheat are mainly associated with the regime of moistening the growing season and overwintering conditions for plants. Winter wheat yield is mainly determined by precipitation of May. The highest productivity is marked with the amount of precipitation of 50-60 mm. By increasing the amount of precipitation (60 mm) or decrease (less than 50 mm), winter wheat decreases. The dependence of grain productivity of winter wheat from hydrothermic factor of the growing season is also significant. Hydrothermic factor equal to 1.4 to 1.6 formed its highest yield, which corresponds to the year with sufficient moisture (climatic norm of 1.1). The main meteorological factors of overwintering for winter wheat are soil freezing and the snow depth. When the soil is freezing for more than 50 cm, the yeald is reduced since frozen soil and snow cover have a direct impact on the soil temperature at a depth of tillering node. Snow depth of 40-50 cm allows to obtain high yields of winter wheat, but a further increase reduces the showings of the yield, as thick snow layer leads to damping-off of plants. It is shown that the winter wheat grain yield in the cultivation of it at a dead fallow under the favorable weather conditions and with an advanced cultivation techniques reaches 4.0-4.5 t/ha and more, even without fertilization. Phenology of winter wheat is submitted.