Influence of sowing time on the yield of spring wheat in Northern Kazakhstan

Abstract

The research was carried out in order to determine the most optimal terms of sowing spring wheat when cultivating on a stubble precursor in the conditions of southern chernozems of the Kostanay region. The terms of sowing of spring wheat of the «Omskaya 18» variety were studied: May 15 (control), May 18, May 22, May 25, May 27, May 30 and June 05 in the fields of the 4-field grain-steam (steam – wheat – wheat – wheat) crop rotation.Soil cultivation technology- No-till.Records and observations were carried out according to the standard generally accepted methodology. An agrochemical survey at the experimental site showed that before sowing, the soil supply with nitrate nitrogen was characterized as low, mobile phosphorus – average, and exchange potassium – very high. On average, for the 2018-2020 years of research, the reserves of productive moisture in the soil during the sowing of spring wheat were characterized as good. It was found that the low  on average 1.47t/ha,  yield of spring wheat at the early sowing date of May 15, 2020, was primarily due to the lack of productive precipitation and high temperatures, which fell on a critical phase of development for the crop, affecting the grain filling. For the period of 2018-2020 years yield apparently were increased. As a matter of fact results get up to +0,43 t/ha for per hectare from 25^th may and  get up to 1,90-1,99 tons for per hectare in average. It was revealed that the sowing dates are reflected on the quality. So, an early date decreases the full-scale grain weight, meanwhile sowing, from 22th May till the 5th June formed the grains of the second class.