In the results of research are presented the regularities of the formation of cenoses of segetal vegetation in field crops, in particular, corn for grain and soybeans, with adaptive tillage systems in the Forest-Steppe zone of Ukraine in order to develop effective, environmentally safe, resource-and energy-saving agrotechnological measures to control the level of contamination of agricultural land. The research was carried out during 2016-2020 in a stationary two – factor field experiment, which includes 5 alternative tillage systems (plowing, flat – cutting processing, differentiated – chiseling, shallow and surface – disking) and 3 fertilizer systems (without fertilizers; earning in the soil by – products of the predecessor; by-products + mineral fertilizers) in a short-term grain crop rotation (winter wheat-corn for grain-spring barley-soy) on gray large-sawn-light loamy forest soils.It was found that in agrocenoses of corn for grain and soybeans during the growing season, a small-year type of contamination is formed with a predominance of representatives of the Poaceae family, the monocotyledonous class, in particular Echinochloa crus-galli L. and Setaria glauca L.The best results in controlling of the development of segetal vegetation on experimental variants were provided by varieties of deep tillage (plow, flat-cut or chisel) against the background of an organic-mineral fertilizer system with the introduction of by-products of the predecessor into the soil and the introduction of mineral fertilizers. Such fertilizer systems decreased the contamination of crops by 38.9%.When cultivating the soil without turning the soil chunk – flat-cut and disking, against the background without fertilizers, the development of segetal vegetation was poorly controlled.Systems of minimized–shallow and surface disk treatments significantly (up to 88%) increased the abundance and (up to 91%) weight indicators of crop weed contamination in the pre-harvest period compared to multi-depth plowing and differentiated system of basic soil tilling.

The purpose of the research is to establish the effectiveness of the use of alternative sources of organic fertilizers in short-rotation grain crop rotations, the influence of the volume of by-products and root residues in combination with the application of mineral fertilizers on the formation of the nutritional regime of gray forest soil. To analyze the impact of different crop rotations saturated with leguminous and grain ear crops on the amount of plant biomass input as an alternative organic fertilizer, to determine the effectiveness of the complex application of by-products and mineral fertilizers. Methods. Research methods are field, laboratory, measuring-weighing, comparative-calculating. The research was carried out in the conditions of the Forest Steppe of Ukraine in a long-term stationary experiment of the Department of Soil Tillage and Segetal Vegetation Control of the NSC «IZ NAAN» on gray forest soil in two short-rotational crop rotations. Results. Based on the results of the research, data were obtained on the influence of different tillage systems, the use of plant by-products in the organo-mineral fertilization system of short-rotation crops on the change in the nutrient regime of gray forest light loamy soil. The level of supply of nutrients in the crop rotation depended on the method of the main tillage, the yield level of the crops of the crop rotation, the amount of plant residues and the content of the main nutrients in them. It was noted that with the long-term use of tillage, the active and loosened 0–10 cm layer of the soil is the most saturated with nutrients, both due to the mineralization of crop residues and due to the localization of the main part of the applied mineral fertilizers, while the lower, 10–40 cm layer was characterized by low security level. Conclusions. Earning by-products of crops by carrying out shelf cultivation of the soil, both in 4 and in 5 field crop rotations, contributes to the differentiation of the 0-40 cm soil layer by the content of humus and biogenic nutrients. With the combined use of by-products with mineral fertilizers, the differentiation of the treated soil layer is more pronounced, which led to an increase in the productivity of crop rotations. The use of leaf-stem mass and root residues of corn as an organic fertilizer has a significant effect on improving soil fertility, due to which the largest reserves of humus are formed in 0-40 cm of soil and recirculation of nutrients occurs.

Мета. Дослідити стан мікробіоценозу ґрунту спонтанно відновлюваного фітоценозу 21-го року самозаростання за внесення мінеральних добрив у дозі N90P40K70 і двоукісного режиму використання. Методи. Експериментально-польовий, лабораторно-аналітичний, мікробіологічні, статистичні. Результати. Оптимізація мінерального живлення відновлюваного фітоценозу сприяє збільшенню чисельності мікроорганізмів: амоніфікаторів у 2,24 раза, іммобілізаторів мінерального азоту — у 1,39, денітрифікаторів — у 3,19, нітрифікаторів — у 1,71, целюлозоруйнівних — у 1,64, актиноміцетів — у 1,17, мікроміцетів — у 1,20, мобілізаторів органофосфатів — у 1,33 раза. Внаслідок застосування двохукісного режиму використання трав’янистих ценозів чисельність мікроорганізмів більшості досліджених груп не змінюється, за винятком денітрифікаторів, целюлозоруйнівних бактерій, мікроміцетів і мобілізаторів органофосфатів. Застосування мінеральних добрив призводить до уповільнення мінералізаційних процесів у ґрунті: індекс педотрофності зменшується в 2,28 раза, коефіцієнт мінералізації сполук азоту — в 1,60, оліготрофності — в 2,25, активність мінералізації гумусу — в 1,65 раза. Відчуження рослинної біомаси несуттєво впливає на перебіг мікробіологічних процесів у ґрунті: індекс педотрофності зростає на 18,2 %, коефіцієнт оліготрофності — на 3,63 %, коефіцієнт мінералізації сполук азоту зменшується на 6,6 %, активність мінералізації гумусу — на 6,2 %. Висновки. Нестача мінеральних елементів у ґрунті перелогу провокує інтенсифікацію мінералізаційних процесів, а оптимізування мінерального живлення рослин фітоценозу сприяє їх уповільненню. Зниження сумарної біологічної активності й підвищення фітотоксичності ґрунту за двоукісного використання травостоїв свідчить про початок процесів виснаження ґрунту.

As a result of many years of research in a stationary field experiment conducted in the conditions of the northern forest-steppe on Gray forest large-sawn light loamy soil, the regularities of the influence of methods of its main cultivation, doses and terms of herbicide application on the level of contamination of crops with segetal vegetation and the competitiveness of winter wheat in short-term crop rotation were established.It was found that the competitive pressure of weeds on winter wheat both for plowing and flat–cutting loosening to a depth of 20–22 cm was minimal and amounted to 6.9–13.2%, and the crop pressure on weed cenosis was noted in the range of 81.5–84.8%. The use of a herbicide based on D. R. prosulfuron (750 g/kg) increased this indicator to 90%.With flat-cutting loosening, the potential contamination of the upper 0–5-centimeter layer of soil, from which the bulk of weeds germinate, in the crops of the studied crop was 31.3–31.8% higher compared to plowing. Indicators of potential contamination and the rate of germination of weed seeds with this method of basic tillage caused a high level of actual weediness of winter wheat crops in a short-term crop rotation. However, systematic tillage without layer turnover ensured gradual self-cleaning of the lower part of the arable soil layer from weed seeds.The highest yield of winter wheat 6.11 t/ha of grain was obtained during plowing and the autumn period of application of the herbicide based on D. R. prosulfuron (750 g/kg) at a rate of 20 g/ha in the development phase of the BBCH 11–13. The use of the herbicide in autumn compared to spring periods provided an increase in the grain yield by 0.24–0.54 t/ha for plowing and by 0.48–0.64 t/ha for non – polar cultivation.Economically, the most appropriate technology for controlling segetal vegetation in winter wheat crops is recognized, which provides for plowing to a depth of 20–22 cm as the main tillage with the introduction of N80P60K80 and earning by-products of its predecessors into the soil. To increase the effectiveness of crop contamination control in the integrated plant protection system, it is also proposed to use autumn application of a herbicide based on D. R. prosulfuron (750 g/kg) at a dose of 20 g/ha in the phase of 2–3 leaves in the culture.

The article analyzes the results of studies conducted in the stationary experiment of NSC «Institute of Agriculture NAAS» to determine the impact of different systems of basic tillage on weed agrocenosis of oats in single and mixed crops with legumes (oats + diaper). The aim of the research is to establish the influence of different systems of basic tillage on the level of weediness of crops. The technology of growing crops in the experiment is generally accepted and recommended for the research area. The obtained research results convincingly show that from the replacement of fallow plowing by 20–22 cm by autumn disc cultivation by 10–12 cm weediness of oat crops at the time of its tillering increased from 15 to 25 pieces/m2 on average during the research or 40%. It was found that sowing oat-diaper mixture with 25% bean component, regardless of the system of main tillage, is an effective phytocoenotic agro-measure of control of segetal vegetation and reduces by 9–20% weed binary crops compared to monocotyledons. The priority of application of additional agrotechnical measure of control of segetal vegetation in agrocenosis of oats by carrying out spring pre-emergence loosening of soil by non-shelf implements by 6–8 cm was proved, which allowed to significantly reduce weed infestation. In particular, the spring pre-emergence loosening against the background of fallow plowing and autumn shallow disc cultivation weed reduction of oat crops decreased by 18 and 25% and 20 and 26%, respectively.

Topicality. In the context of the economic and environmental crisis, efficient utilisation of land resources, optimisation of the structure of agricultural areas in all natural and climatic zones, considering the particular characteristics of each region, and environmental conservation are important factors for sustainable development of agricultural production. Crop rotations should be dynamic, combined and intensive, and their implementation should always be based on scientific justification. Purpose. To determine the influence of the structure, set and arrangement of field crops in various crop rotations on the total productivity, yield and seed quality of soybeans. Methods. The research was conducted in the subzone of unstable moistening of the Left-Bank Forest-Steppe of Ukraine on typical low-humus chernozem at the Panfyly Research Station of the National Research Centre "Institute of Agriculture of the NAAS of Ukraine". Soybeans were grown in 6-8-field crop rotations under an organic-mineral fertilisation system to study the influence of predecessors on productivity, yield and seed quality. The crop cultivation technology in the experiment is generally accepted and recommended for the research zone. Methods used: long-term field, laboratory-field, laboratory (chemical, physicochemical), mathematical and statistical. Results. The long-term stationary field experiment on the study of crop rotations, which was established in 2001, convincingly proves that 6–8-field crop rotations with proportion of soybeans from 12.5 to 16.7 % were highly effective in this zone over 2016–2020. The soybean seed yield, which was grown after buckwheat, winter and spring wheat as predecessors and the corresponding crop set in crop rotations, was in the range of 2.92–3.47 t/ha with oil content in seeds of 20.7–21.5 %. The economic efficiency of soybean cultivation in the structure of various crop rotations was as follows: net operating profit – 12.55–16.76 thsd UAH/ha at a level of profitability – 116–152 %. Conclusions. It was found that the most productive in the Left-Bank Forest-Steppe zone was a 6-field crop rotation with proportion of soybean of up to 16.7 % (soybean – winter wheat – sugar beet – spring barley – maize for grain – buckwheat) under the organic-mineral fertilisation system (by-products of the predecessor + N0P40K40). The yield per 1 ha of arable land was 4.79 t of fodder units and 1.01 t of digestible protein at a net operating profit of 16.76 thsd UAH/ha and a profitability of 152 %. Key words: crop, crop rotation, yield, fodder units, crude protein, oil content, profitability, net operating profit