Relevance of research. In order to ensure energy independence and food security of the state in the context of current climate change trends, the importance of reclaimed territories is increasing. By objectively assessing the agro-resource potential of individual regions and developing a strategy for its rational use, it is possible to significantly improve the productivity, stability, environmental balance and economic efficiency of agro-ecosystems. Objective of research. The objective of the research is to assess the water supply of the territory of Ukraine under changing climate and establish the mechanism of its influence on the bioproductivity of agricultural lands, theoretically substantiate and elaborate perspective options for the development of bioenergy reclaimed agroecosystems and specify the research areas on the reassessment of rational use of water resources in optimal combination with other components of agricultural production in a rapidly changing climate. Research methodology. The estimation and forecasting of the conditions of water supply were carried out on the basis of the climate water balance (CWB). Spatial analysis of climate data and crop yields was performed by IDW interpolation using QGIS3 software. To determine the promising areas for the development of agricultural production systems the results of stationary field experiments were used, which were processed by conventional methods of system analysis. Promising scenarios for the development of reclaimed agroecosystems were created using multivariate computer simulation in the “Agroecosystem” software package. Research results and main conclusions. It was established that, compared to 1961-1990, the area with a water supply shortage increased from 56 to 60%, and the area of sufficient and excessive humidity, on the contrary, decreased from 33 to 24%. Provided that the general trend of increasing temperature in the territory of Ukraine continues, the share of agricultural lands with scarce water balance by 2050 may increase up to 67%, and by 2100 – up to 80% of their total area. It was found that grain production remains at the level of 1990 in the steppe zone due to almost annual lack of moisture while in the forest-steppe and Polissia regions it increased up to 80-90%. It is important that, even in the humid zone, the risks of adverse water and air conditions for soils increased significantly, particularly as regards the soils of light texture. Consequently, sustainable high-yield agriculture without the development and implementation of effective regional measures on improving water supply is becoming problematic in most of Ukraine. Based on computer simulation, it was proved that the transition of domestic agricultural production to the principles of balanced organic food production, industrial raw materials and bioenergy resources will dramatically increase the profitability of agricultural enterprises, improve the ecological state of the environment and create a comfortable living environment for rural population and substantially strengthen the food security and energy independence of the state. Prospects. To achieve high efficiency and competitiveness of the agroindustrial complex of Ukraine, it is necessary to carry out a comprehensive study on the reassessment of rational use of water resources in optimal combination with other components of agricultural production under rapidly changing climate. On this scientific basis, it is advisable to create a unified system of water management for the effective use of the state's land fund, in particular the reclaimed areas.

Relevance of research. Due to ongoing climate change, almost the entire territory of the Steppe of Ukraine by annual humidity factor belongs to the dry and very dry zones, the relative area of ​​which has increased by 13.2% of the total area of ​​the country compared to the 1960-1990s. At the same time, for today in Ukraine only about 500 thousand hectares are actually irrigated, that is 19% of the potential area. Purpose of research. To determine the patterns and trends of climate change in the western part of the dry Steppe of Ukraine and analyze the economic indicators of production activity in the region as to the variable weather conditions. Research methodology. Climate change was estimated on the basis of Climate Water Balance (CWB) and Hydrothermal Coefficient (HTC) values. The analysis of the economic efficiency of agricultural production was carried out by analyzing the statistical data for Odessa region and for the chosen agricultural enterprise. Research results and conclusions. The use of significant heat supply in the dry Steppe zone is limited by insufficient water supply conditions. In the years of 1991-2016 the average annual rainfall was 480 mm and since the early 2000s there has been a slight increase in that. However, even having 500-550 mm of average annual rainfall that has been observed over the past five years, it is not enough for providing high-yield agricultural production. High thermal regime couses high evaporation that in turn, leads to water supply deficit, which at the end of the growing season amounts to 336-436 mm. According to the HTC index in the region 80% of cases show severe and moderately arid vegetation conditions. At the same time, irrigation area in the region has decreased to a minimum, which has led to the domination of winter cereals and sunflower in the cropping system. Under variable weather conditions, winter wheat yields ranged from 19.4 to 38.5 c/ ha (31.4 c/ha on average) and sunflower - from 12.2 to 21.4 c/ha (17.4 c/ha on average), winter rape - from 13.1 to 20.9 c/ha (18.2 c/ha). It was proved a close direct relationship between the sale price of products of all studied crops and their cost price, as well as the inverse relationship of these indicators with the crop yield. The profitability of winter wheat from 2011 till 2016 ranged from 17 to 153 USD/ha with an average value of 86 USD/ha, winter rape - from 39 to 273 USD/ha with an average value of 166 USD ha and sunflower - from 116 to 315 USD/ha with an average value of 192 USD/ha. Corn and soybeans have proven to be unprofitable in some years, which obviously explains rather small areas under these crops in the region. Above mentioned demonstrates the high economic instability of agricultural production in changing weather conditions, which is accompanied by significant risks for producers, especially when attracting credits. This situation, in turn, leads to a limited use of intensification means, in particular mineral fertilizers, which promotes agrochemical soil degradation. Under unstable water supply, the magnitude of net profit variation per hectare of arable land in Odessa region is 33-188 USD/ha (111 USD/ha on average). It is possible to increase these indicators by increasing the share of winter rape in the cropping system. With the optimization of the water and air soil regimes as well as crop rotation factor, the profitability of agricultural production in the region can be increased up to 580-600 USD/ha. Similar results were obtained after analyzing the statistical data from the southern regions within the dry steppe zone.

The analysis of information support in the agricultural production has been done. IWPLR is developing now a «System of information support for agriculture», which has a two-level structure of decision-making and contains a database. At the level of «economy» the system, taking into account both the economic priorities and the wishes of the farms as well as soil-climatic and environmental constraints helps the agricultural producers (the users of the system) to define a set of priority crops using a subsystem «crop rotation». At the level of «field» the system, using the database helps the users to calculate the flow process charts for identified priority crops. The database of the system consists of five sections: «agriculture», «agri-resource potential» «reclamation», «mechanization and processing», «animal production» and provides some background information for agricultural producers.

Modern climatic changes, namely significant warming in the northern Forest-Steppe and Polissia zones of Ukraine, provide opportunities for the cultivation of a number of grain and leguminous crops (maize for grain, soybeans, sunflower, and others), previously uncharacteristic of this region. Among the above-mentioned crops, corn has the greatest grain yield potential, therefore it is one of the most common crops in world agriculture. If 10-15 years ago corn was not grown for grain in the Polissia zone, then in recent years its sown areas have grown significantly, and the yield in some years is not inferior to the regions of the Forest Steppe and Steppe, which are traditional for this crop. The results of experimental studies of the station showed that under favorable conditions on the most fertile slopes of the drained sod-podzolic soils of the Western Polissia zone, with intensive technologies, it is possible to obtain more than 10-12 t/ha of corn grain. The analysis of hydrothermal indicators shows that with the current indicators of heat supply of the growing season in the zone of Western Polissia on mineral soils, it is possible to achieve not only early-ripening, but even medium-early hybrids of corn with FAO up to 280-300. Drained peat soils, due to their high nitrogen content and sufficient amount of moisture, have sufficient potential for obtaining a high yield of corn grain. However, its indicators over the years of research vary greatly and depend to a large extent on the agro-meteorological conditions of the growing season. It has been established that the main limiting factors for achieving a high yield of corn grain on peat soils are less favorable microclimatic features (less amount of active heat, shorter growing season and frost-free period, etc.) compared to adjacent sod-podzolic soils located nearby on dry land. It has been experimentally established that under conditions of minimum duration without a frost period, only the most early-ripening hybrids of corn with FAO up to 220-240 will have time to form a full-fledged crop of grain on drained peat soils in the Western Polissia zone. By choosing late-ripening hybrids, there is a risk of a significant shortfall in the harvest due to the premature termination of vegetation caused by early autumn frosts. It was established that the highest yield of corn per grain, both on sod-podzolic and peat soils, was provided by the organo-mineral fertilization system, which was based on the application of complete mineral fertilizer at the rate of N₉₀Р₉₀К₉₀ on turf-podzolic soils and N₃₅Р₆₀K₁₂₀ on peat soils in combination with phosphorus mobilizing drug Rice Pi. The use of the organo-mineral fertilization system (N₉₀Р₉₀К₉₀ + phosphorus mobilizing drug Rice Pi) ensured an increase in the yield of corn on sod-podzolic soils by 30,2 ct/ha compared to the basic fertilization system (N₃₀Р₃₀К₃₀). The use of the organo-mineral fertilization system (N₃₅Р₆₀K₁₂₀ + phosphorus mobilizing drug Rice Pi) ensured an increase in the yield of corn on peatlands by 56.8 ct/ha compared to the natural background of fertility.

The article presents the results of long-term experimental studies on the effect of different methods of main tillage on soil fertility and crop productivity when applying different degrees of fertilization. Field research was conducted during 2013-2020 on the lands of the Poltava Research Station of the Institute of Pig Breeding and Agro-Industrial Production of the National Academy of Agricultural Sciences. It has been established that the systematic use of organic and organic and-mineral fertilization systems improves the nutrient regime of typical black soil with differentiation of the arable layer by the amount of phosphorus and potassium when applying long-term minimal loosening. There is a tendency towards an increase in density in the layers of 20-40 and 40-60 cm when applying systematic shallow tillage, where this indicator exceeds the upper limit of the optimal range of 1,0-1,3 g/cm3. Application of manure and mineral fertilizers compared to surface loosening makes it possible to additionally annually sequester 0,3-0,4 t/ha of carbon, which is equivalent to 1,2-1,6 t of carbon dioxide. By the average multi-year yield of corn per silage, shallow loosening is inferior to combined tillage by an average of 10%. Tendencies to a decrease in the average long-term productivity of soybean, spring barley, and pea crops when using minimal tillage compared to the combined one are manifested only in certain fertilizer options. Under optimal conditions of heat and moisture supply, the ratio of grain and straw in soybeans decreases. On winter wheat, after peas, there is a tendency towards the preference of shallow loosening. The ratio of wheat grain to straw increases significantly under favorable conditions. Corn responds better to the combined tillage system, which prevails shallow loosening in terms of grain yield by the fertilizer options by 6-10%. Under favorable conditions, the ratio of stems to grain increases significantly, especially on fertilized grounds. From the studied crops, the productivity of sugar beets fluctuates to a greater extent to the conditions of the year, and to a lesser extent - winter wheat, grown after peas and corn for grain. By the average long-term crop productivity, shallow tillage is inferior to combined tillage by 4-8% having a confidence level of 5%. When applying manure, it is advisable to use a combined system of soil tillage, for plant-oriented agrarian production, it is economically advisable to use surface loosening for all crops.

The article presents the results of research on the assessment of modern climate change and the impact of weather conditions on the yield of main field crops when using different feeding systems and tillage. It was established that during 1991-2020 the average annual air temperature in the region increased by 1,1oC, and the annual precipitation decreased by 5%. Under such conditions, the frequency of recurrence of highly and moderately arid conditions of the growing season increased from 47% in 1961-1990 to 61% in 1991-2020, however the probability of forming a sufficient moisture supply decreased by half. Based on the results of the Climate Water Balance (CWB) assessment, it was specified that in the western part of the Left-Bank Forest-Steppe, according to average long-term data a negative WBC has been formed since June, and by the end of August its deficit reaches over 140 mm or 1,400 m3 / ha. In general, by the end of the period for 1991-2020, the deficit of WBC increased by 82 mm. Based on the information database made on the results of long-term stationary field experiment at Poltava Research Station of the Institute of Pig Farming and Agroindustrial Production of NAAS, the yield potential of main crops and the productivity of typical chernozem subject to the optimization of crop rotation and nutrient and water-air regimes, were evaluated. It was determined that optimization of crop rotations increases plant productivity by 19%, fertilizer systems - by 19-36%, irrigation - by 94%, irrigation and fertilization - by 130-153%, and a comprehensive combination of all agronomic measures - by 200% and more. It was also established that the total productivity of crop rotation under different systems of basic tillage remains virtually unchanged and enables to obtain average by year 3.6-3.8 t kd / ha against the background of natural soil fertility. From the organic fertilizer systems, the efficiency of using crop by-products as fertilizers is 10% higher than using manure and practically does not concede to organomineral fertilizer systems. As a result of research it was found that in the region in recent decades there is a tendency of deteriorating growing conditions of main field crops, which is reflected in the formation of low yields and poorer crop rotation productivity, significant variation of these factors in terms of weather, especially when having high soil fertility.