The interrelation between the productivity of winter wheat and weather conditions in autumn and early spring periods in the Northern Steppe of Ukraine

The main objective of the study was to create scientific and methodological bases for the development, implementation and correction of ecologically adaptive technologies of winter wheat growing in the northern Steppe of Ukraine, depending on the terms of the cessation of vegetation in autumn and its recovery in spring. Winter wheat was sown after black fallow and corn for silage at different dates of sowing from August 25 to October 2, at the intervals of 6-7 days. It has been proved that the terms of the end of autumn vegetation of winter wheat in the northern Steppe of Ukraine influences crops productivity. Higher productivity is formed when growing winter wheat after black fallow and maize for silage in the years when the autumn vegetation ends in the third decade of November. The productivity is respectively 5.67 and 5.58 t/ha. Earlier and later cessation of vegetation causes a decrease in the productivity of winter wheat. The lowest productivity after the two predecessors is formed in the years when the autumn vegetation ends in the first decade of November. For all periods of the autumn vegetation cessation the highest productivity after black fallow is provided by the crops that are sown on September Only in the years with the very early cessation of autumn vegetation winter wheat sown on September 2 is more productive than that sown on October 2. The productivity is respectively 5.17 and 4.68 t/ha. In all years, with the later cessation of autumn vegetation, late crops form higher productivity than early crops sown on September 2. When winter wheat is sown after the maize for silage, in the years with the very early and late cessation of autumn vegetation, the crops sown on October 2 have higher productivity than the crops sown on September 17. The later the vegetation is recovered, the less productivity occurs. In the case of early vegetation recovery (the 3rd decade of February), the productivity of uneven-aged crops is almost the same and ranges from 6.44 to 6.96 t/ha. At the case of late vegetation recovery (early April) the crops sown from 10 to 25 of September, form higher productivity. The average productivity over the years of research was 3.86 – 3.91 t/ha. The productivity of crops sown on September 2 and October 2 is almost the same and is respectively 2.99 and 2.88 t/ha, but it is much higher than the productivity of crops sown on August 25.