CROP YIELDS OF WINTER WHEAT IN SOUTH-EASTERN AREAS OF WESTERN SIBERIA DEPENDING ON SEEDING RATES AND PERIODS
The aim of the study was to find out the dependence of productivity of varieties of soft winter wheat from planting dates and seeding rates, its relationship with the dynamics of hydrothermal conditions of autumn-winter-spring period in the conditions of Northern forest-steppe zone of the foothills South-East of Western Siberia (Kemerovo region). The results of 2010-2013 research of soft winter wheat yield dependency on seeding rates and seeding periods are shown, as well as the correlation of yield with hydrothermal conditions of the autumn-winter-spring crop seasons, carried out in northern forest-steppe foothill areas of South-eastern areas of Western Siberia. Three seeding periods were investigated, they are: early (2 <sup>nd</sup> ten-day period of August), medium (3 <sup>rd</sup> ten-day period of August), late (1 <sup>st</sup> ten-day period of September) with three seeding rates: 5,5; 6,0 and 6,5 mln germinating seeds per hectare, four germinating soft winter wheat varieties: Omskaya 4, Omskaya Ozimaya, Novosibirskaya 40 and Novosibirskaya 51. The highest yields were shown when the seeding period fell on the 3 <sup>rd</sup> ten-day period of August and at the seeding rate of 6 mln germinating seeds per hectare. Seeding time and seeding rate had no significant impact on the interplay between yields and meteorological conditions during the autumn-winter-spring season. Yields were limited by ambient temperatures in October, December, March (r = - 0, 69 to 0, 93), February (r = 0, 85 to 0, 90); by the amount of precipitation in October, November, February (r = 0, 52 to 0, 90), by the height of snow cover during November - April (r = 0, 67 to 0, 90).