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.