Особливості вирощування гречки в післяукісних посівах

Abstract

Досліджено вплив доз внесення мінеральних добрив на фоні поверхневого обробітку ґрунту і оранки на урожайність гречки сорту Любава в післяукісних посівах. Кращою дозою внесення мінеральних добрив під післяукісні посіви гречки виявилась N90Р60, але найбільша окупність добрив приростом зерна і найменша його собівартість була за внесення N60Р30. Вивчено закономірності росту і розвитку рослин гречки під впливом обробітку ґрунту, удобрення, способів сівби, норм висіву насіння. Розроблено технологію вирощування гречки в післяукісних посівах в умовах північного Степу. Встановлено, що в неполивних умовах північного Степу України можливо вирощувати післяукісну гречку на зерно після жита озимого на зелений корм і культур, які рано звільняють поле. Висівати гречку доцільно на фоні поверхневого обробітку ґрунту з міжряддями 45 або 70 см – норма висіву 2,0 млн схожих насінин/га. Норма висіву при сівбі з міжряддями 15 см сівалкою СЗС-2,1 – 2,5 млн схожих насінин/га. The influence of mineral fertilizer norms on the background of surface cultivation of soil and plowing on the crop yield of buckwheat variety Liubava in post-harvest crops, as well as the reaction of crop on seeding methods and seeding rates, was investigated. Field experiments on fertilizing and soil cultivating were laid in the farm holding "Victoria" of the Magdalynivka district of the Dnipropetrovs’k region. The studies of the sowing methods and the seeding rates of the buckwheat were carried out in LLC "Svitanok" of Novomoskovs’k district of the Dnipropetrovs’k region. Soil of experimental plots – ordinary chernozem, middle loamy. The content of humus in the arable layer of soil is 4.0–4.2 %, mobile nitrogen – 1.6–1.8 mg, P2O5 – 10.3–10.5 %, exchangeable potassium – 12.4–13.5 mg per 100 g of soil. After harvesting the rye for the green feed, the soil was cultivated with a heavy harrow to a depth of 8–10 cm, and the separate plots were plowed to a depth of 20–22 cm. Under the pre-sowing cultivation, the mineral fertilizers were applied according to the experimental scheme. Buckwheat seeding was carried out with a seed drill SZ-3.6 with a seeding rate of 2.5 million of germinated grains per hectare. After sowing, the field was pressed with cross-kill rollers. Buckwheat was harvested in a two-phase way when browning of 75 % grains. In the Steppe, in the post-tipped period, an average of 142 mm of precipitation falls, which is sufficient to maintain optimum soil moisture for growth and development of buckwheat plants. In 40 % of years their number may decrease to 107–124 mm or increase to 178–210 mm. During the years of our research, the buckwheat moisture content was satisfactory. The results of the research showed that increasing the seed rate and the widening spaces between rows, decreases the plant nutrition, increases the unevenness of their placement, decreases their moisture content, nutrition and illumination, which leads to the reduction of agrophytocenosis of buckwheat due to the loss of weaker plants. In ordinary crops with row spacings of 15 cm and direct sowing with seed drill SZS-2.1 in plants due to less branching-out than in wide-rowed, a smaller number of inflorescences and grains were formed, which reduced their productivity and crop yield, despite a larger number of plants per hectare. Within the ordinary and wide-rowed crops by productivity the plants differed a little. With thickening of plants in all sowing methods, the productivity of buckwheat naturally decreased. Thus, if the seed is sown at a rate of 1.0 million per hectare on average for 2013–2015 at ordinary sowing (15 cm), the weight of the grains from the plant was 0.63 g, at wide-rowed (45 cm) – 0.80 g, then at a rate of 3.5 million/ha – 0.23 and 0.33 g, respectively. The most favorable ratio of the number of plants on the area and their productivity was formed at sowing using the wide-rowed method (45 cm) and the seeding rate of 2.0 million /ha, which provided the highest crop yield (1.08 t/ha) with minimal energy consumption. The crop yield of buckwheat grain was reduced by 0.06 t/ha at the sowing with spacing between rows of 70 cm, by 0.17 t/ha – at direct sowing with a seed drill SZS-2.1 and by 0.18 t/ha – in an ordinary sowing crop. The optimum seeding rates for buckwheat at wide-row sowing manner (45, 70 cm) are 2.0 million ha/ha, and ordinary (15, 22.5 cm) – 2.5 million/ha. Substantially influenced on growth of buckwheat plants and their branching-out the soil cultivation and fertilization. The best rate for mineral fertilizer application for post-topped buckwheat was N90P60, but the highest payback of fertilization with grain increments and its lowest cost was observed when introducing N60P30. In most years of researches, plowing did not have the advantage over the surface soil cultivation, and due to more cost, its holding proved to be an economically disadvantageous agro-investment in the technology of growing post-harvested buckwheat.