Оптимізація норми висіву насіння сої залежно від групи стиглості сорту для умов Центрального Лісостепу України

Abstract

Soybean is a crop plastic to such characteristic as plant allocation on the area. Numerous studies of different varieties demonstrate this fact. That is why optimal density of soybean plants must be determined by experimentally research for each separate variety. The research aim is to establish optimal seeding rates of soybean varieties of early-ripening and fast-ripening groups. The experiment was founded in the conditions ofprivate farm “Pryorillya” Novi Sanzhary district, Poltava oblast. The farm is situated in the central forest steppe of Ukraine. This part of our country has temperate-continental climate. The research object is soybean varieties Terek, Vilshanka, Kuban and Luna. The fields of our experiment were sown by winter wheat last year. The soil is deep chernozem soil, with little humus and average humus content. The technology of soybean cultivation in the experiment was characterized by the following stages: decortication of stubble remains was donein the second decade of July, ploughingto the depth of 22-24 cm was done in the second decade of September. In spring when soil became physically mature closing of moisture was conducted. Before sowing soybean there was possibility of doing two cultivations depending on weeds growth. Pre-sowing tillage of experimented plots of land was made in the second decade of May: cultivation to the depth of 10-12 cm including harrowing to the depth of 6-8cm. Soybean was sown by drilling method with row-spacing of 15cm in the second decade of May. The depth of seed covering was 4 cm,seeding rate for each variant was applied according to the experiment scheme. Seeding material was treated with rhizotorphinbefore sowing. Weed was controlled by one pre-sowing and two post-sowing harrowing by light, spike-tooth harrow.Pre-sowing harrowing was used in five days after crop sowing. The first pre-sowing harrowing was done in the period when rows marked and the second pre-sowing harrowing was done while coming two true leaves of soybean plants. All other technological operations concerning crop cultivation for all variants of the experiment were done similarly. According to the research results during 2013-2015 yearsamong fast-ripening varieties variety Vilshanka formed the highest yield. Yield of variety Vilshanka varied from 2.26 to 2.46 t/ha. Productivity of variety Terek in 2013-2015 years was at the level of 1.91-2.34 t/ha. Depending on density of plants on sown area yield of variety Terek was the greatest ( 2.25 t/ha) on the variant with seeding rate of 900 thousand/ha. Maximal yield of variety Vilshanka of 2.43t/ha was gained on the variant with seeding rate of 900 thousand/ha. During 2013-2015 years variety Kuban produced the highest yield among early ripening varieties. Yield of variety Kuban varied from 2.28-2.64 t/ha. Variety Luna formed yield at the level of 2.26-2.44 t/ha during the same period. Depending on density of plants on sown area variety Kuban produced the greatest yield of soybean (2.57 t/ha) on the variant with seeding rate of800 thousand/ha. Seeding rate of 800 thousand/ha influenced on productivity of variety Luna in the best way. Yield of variety Luna was 2.41t/ha. Conclusions and perspectives of further researches. Impact of variety qualities and seeding rates on the level of soybeanyield has been established. Influence of weather conditions on formation of yield of soybean varieties of different ripeness group has been analyzed. It has been determined that during three research years the most favourable weather conditions for yield formation were in 2015. Early-ripening varieties produced higher yield among the groups of variety ripeness. The seeding rate of 900 thousand/ha affected yield formation of varieties of fast-ripening group in the best way. For varieties of early-ripening group optimal conditions for gaining high yield were created in agrophytocenosis with seeding rate of 800 thousand/ha. On average during three research years variety Kuban produced the highest yield at the levelof 2.57 t/ha.According to duration of vegetation periodvariety Kuban belongs to early-ripening group. Variety Vilshanka formed the highest yield at the level of 2.43 t/ha among fast-ripening varieties. Thus, it has been defined that for optimization of conditions of soybean growth and development nutrition area must be corrected according to the group of variety ripeness. That is whystudy of impact of soybean plant density for new varieties is a perspective of further research.