THE EFFECTIVENESS OF ENVIRONMENTALLY SAFE PREPARATIONS OF COMBINED ACTION ON THE PRODUCTIVITY OF HELIANTHUS ANNUUS L. AT DIFFERENT DENSITIES OF THE CENOSIS

Abstract

The purpose of the article is to establish the effectiveness of foliar treatment of plants with environmentally safe drugs of combined action on the productivity of new sunflower hybrids under non-irrigated conditions of the Steppe zone of Ukraine. Materials and methods. The field experiments were carried out during 2021- 2022 at the experimental field of the Mykolayiv DSDS IKOSG of the National Academy of Sciences in nonirrigated conditions on southern chernozem. The content of humus in the arable layer of the soil is 2.90%, the depth of the humus layer is 0-30 cm, the depth of the transitional layer is 30-60 cm. Climatic conditions of the place of research are continental, characterized by sharp and frequent fluctuations in annual and monthly air temperatures, the harsh GTK of the observation area. The average annual precipitation is 360-380 mm, during the period of spring-summer vegetation of winter crops - 170 mm. The study was carried out by establishing a three-factor field experiment, where factor A is the sunflower hybrids selected by the Institute of Plant Breeding. V.Ya. Yuryeva National Academy of Sciences – Yarylo,Vyriy, Bright, Blysk and Epicurus; factor B – different plant densities (30, 40 and 50 thousand/ ha) and factor C – treatment of vegetative plants in the budding phase with biological preparations (Helafit Combi, Organic Balance and Biocomplex BTU). Processing of sunflower plants according to the research scheme was carried out using a knapsack sprayer. The repetition of the experiment is three times, the sown area of the plot of the first order is 168 m2, the accounting area is 120 m2. The field experiment is located along the predecessor of winter wheat. Fertilizers were applied under the main tillage in a dose of N30P30K30. Sowing is carried out with a row spacing of 70 cm in the last decade of April. Formation of plant stand density was carried out manually to a given density in each row. Accounting for yield and assessment of crop structure was carried out by manual threshing of plants selected from the accounting area of experimental plots and conversion to 8% seed moisture. The actual yield was calculated based on the basic moisture content (8%) and taking into account the presence of impurities. The results. From the results of observations, it was established that thinning, or vice versa, thickening of sowing did not have a significant effect on the flow of the main interphase periods of culture development throughout the entire growing season of sunflower plants. the treatment of sunflower plants with biological preparations contributed to the extension of the vegetation period of all studied hybrids in the interphase period of flowering - full maturity. This prolongation of the generative period in 2021 was more effective, which is explained by favorable weather conditions during the growing season. In the areas where foliar treatment of plants with Helafit Combi and Organic Balance was carried out, the prolongation of the seed ripening period by 8-10 days in 2021 and by 2-7 days in 2022 was recorded on average for hybrids. Research has established that the hybrids were close in terms of resistance to pathogens of the main diseases, but the Yarylo and Epicurus hybrids had a slightly lower percentage of plants affected by fomosis compared to the Blysk, Bright and Vyrii hybrids. Biological preparations also had a positive effect on the productivity of the studied agrocenoses. Conclusions. Foliar treatment of sunflower plants with ecologically safe drugs of combined action contributed to the prolongation of interphase periods in the second half of the growing season of all studied hybrids. Treatment of plants with environmentally safe drugs contributed to the reduction of the level of lesions of all hybrids by pathogenic microflora, the most fungicidal effectiveness was achieved by Helafit Combi and Organic Balance. All hybrids formed the highest yield at a density of 40,000 pieces/ha. Thickened crops up to 50,000 units/ha were inferior in terms of yield to options with a stand density of 40,000 units/ha and were almost at the same level as options with 30,000 units/ha. Hybrids Yarylo, Epicurus and Bright were significantly inferior in productivity, however, their foliar treatment also had a related tendency to increase their productivity.