А. Rozkov., Doctor of Agrarian Science
М. Bobro., Doctor of Agrarian Science
Т. Ryzhyk., assistant lecturer
Kharkiv National Agrarian University by V. V. Dokuchayev
Poor condition of winter crops causes an urgent need in agrotechnical and selective investigations in the direction of establishing the optimal and acceptable sowing terms. Winter crops which are sown in the optimal terms for each natural and climatic zone show the best indices of productivity and winter resistance. It is necessary to set them considering the peculiarities of the varieties, predecessors, fertilizers, soil moisture reserves and other factors.
In order to manage the processes of crop formation it is necessary to have the clear idea about the interaction of all the factors which affect the crop capacity.
The main factor of winter wheat productivity increase is to improve the sowing structure which is determined by productive stalk density that primarily depends on the seeding rate, sowing terms, field seed germination and survival of plants.
The aim of the research is to determine the impact of different variants of the sowing terms in interaction with the seeding rate on grain productivity of the soft winter wheat of Astet variety for the specific soil and climatic conditions.
The experiments were carried out in 2007-2009, 2014 at the experimental field of KhNAU by V. V. Dokuchayev in the field vapour grain cultivated crop rotation of the Plant Growing chair according to the conventional methods. Three variants of the sowing terms were studied in the experiments: the 5 – 7-th of September (the first control), the 15 – 17-th of September (the second), 25 – 27-th of September (the third) and four variants of the seeding rates: 4,0; 4,5; 5,0 and 5,5 mln. of seeds/ha. Winter wheat with the presented collection of the variants was sown after two predecessors: black vapour and buckwheat.
As the result of the research it was established that the highest grain productivity of the winter wheat of Astet variety on average for four years (2007 – 2009, 2014) – 5,60 t/ha, was achieved after black vapour during sowing on the 15 – 17-th of September with the seeding rate of 5mln. of grains/ha.
After buckwheat the choice of the sowing time to form the highest grain productivity depended from the weather conditions of the first half of the vegetation of the crops. So, the maximum level of grain productivity of plants in 2007 and 2014 on average according to the seeding rates was on the variants of the second sowing term (the 15 – 17-th of September) 5,57 and 4,89 t/ha correspondently. In 2008 and 2009 the maximum grain productivity of winter wheat on average according to the seeding rates was 5,35 and 4,07 t/ha correspondently, was gathered on the variants of sowing on the 5 – 7-th of September.