The article highlights the research results on the assessment of natural moisture supply in Ukraine, the state of water resources and agricultural production in the face of modern climate change taking into account the forecast for the medium and long term prospects. It was established that the rate of air temperature growth for the period of 1975-2019 in Ukraine ranges from 0.61 to 0.82oC, while in neighboring post-Soviet countries (Russia, Moldova, Belarus) – this figure is 0.47 - 0.59oC, and in the northern hemisphere and Europe – it is 0.34 and 0.47oC respectively. These data show that the rate of air temperature rise in Ukraine is much higher compared to European countries and the whole world. The rapid rise in average annual temperature in Ukraine is not accompanied by a significant increase in precipitation. Its amount in Ukraine as well as in some other regions remains virtually unchanged. Due to the steady increase in temperature, the area of ​​Ukraine with a significant deficit of natural moisture supply for the period of 1990-2015 increased by 7%, and with excessive and sufficient natural moisture supply, on the contrary, decreased by 10%. If the current warming rates are kept until 2050 and 2100, the territory of the country with insufficient humidity will increase up to 56 and 71%, respectively. As a result of such changes, there is a high probability of medium and long-term prospects of increasing arable land with insufficient natural moisture supply up to 20.6 million hectares (67%) and up to 24.9 million hectares (80%) with a simultaneous decrease in arable land with sufficient natural moisture supply up to 5.5 - 1.8 million hectares. At present, the potential total evaporation is 40-45 km3/year higher than in 1990. As a result, despite the decrease in water consumption, the total amount of water consumption taken from the territory of Ukraine is 20-25 km3 higher. Further climate change will lead to an increase in the volume of additional water consumption till 2050 by 80 km3, and till 2100 - by almost 150 km3 compared to 1990. Modern climate change has significantly affected the cropping systems and their productivity at regional level. The average yield of grain and legumes in the Forest-Steppe and Polissya compared to 1990 increased by 46-61%, and in the Steppe it decreased by 10%. A similar trend is observed with regard to the changes in the productivity of other major cereals, except corn, the yield of which increased in all areas, but in the Forest-Steppe and Polissya by 71-82%, and in the Steppe - only by 9%. The general increase in the production of grain and legumes in the country for the last years was only due to more humid regions - Polissya and Forest-Steppe. Climate change, which has already taken place, proved to be favorable for the spread of the most economically profitable crops in the north of the country, while limiting their production in the south. Thus, in the face of climate change, the conditions of moisture supply in the territory of Ukraine are the main limiting factor that limits not only the level of crop productivity, but also the use of natural and anthropogenic potential of agriculture.

The necessity and the basic directions of the scientific vision of further reforming the systems of water resources and land reclamation management are determined. The need for such a reform is dictated by the fact that, despite the adoption on October 4, 2016, by the Verkhovna Rada of Ukraine of the Law "On Amendments to Certain Legislative Acts of Ukraine on Implementing Integrated Approaches to Basin Management" and a number of by-laws, the system of water management and land reclamation management in Ukraine still remains virtually unreformed since post-Soviet times as two mutually exclusive functions remain in this system: the water management function and the land reclamation management function. Moreover, the statutory grounds for the introduction of integrated basin management have been deliberately used to eliminate economic entities which managed reclamation infrastructure, which has made it much more difficult to separate the above-mentioned functions, as required by Directive 2000/60/EC of the European Parliament and the Council of Europe “On establishing a framework for Community action in the field of water policy”, the implementation of which into Ukrainian law is a mandatory task under the Association Agreement with the EU. Recent adoption (on February 17, 2022) by the Verkhovna Rada of Ukraine of the Law “On Organization of Water Users and Stimulation of Hydrotechnical Land Reclamation” was confirmed by the President of Ukraine on May 6, 2022. It is an important step towards reforming the water management as for the first time in Ukraine the law introduces a new organizational and legal form for the management of reclamation systems, namely water user organizations. But this Law does not address the main issue of the reform - the separation of the above-mentioned functions. Therefore, the success of further reforming of the systems of water resources and land reclamation management will directly depend not on the speed of development and adoption of bylaws to the Law “On Organization of Water Users and Stimulation of Hydrotechnical Land Reclamation”. It will depend on the earliest possible adoption of the “Concept of reforming the water management system of Ukraine” by the Government of Ukraine, the project of which was prepared and approved by all interested ministries and departments in 2019, but was deliberately blocked by then leaders of the Ministry of Ecology and Natural Resources of Ukraine. Therefore, the work on reforming the systems of water resources and land reclamation management is unsystematic and, in many cases, the practical steps being implemented, especially in improving the structure of the State Agency Water Resources of Ukraine, are mostly destructive. Minimizing their negative impact will require considerable efforts and time. This article aims at scientific substantiation of the list and sequence of measures, including at the legislative level, the implementation of which will bring the systems of water resources and land reclamation management in Ukraine in line with European water legislation, and thus ensure full implementation of the provisions of integrated management on the basin principle not only formally but also in the spirit.

Climate change has caused rapid soil dehydration in Ukraine; therefore sustainable agriculture will only be possible applying throughout irrigation or water regulation. Meanwhile, the use of the irrigation and drainage systems potential remains extremely unsatisfactory. In 2019, 532,000 ha were actually irrigated, and water regulation was performed on less than 300,000 ha. The purpose of the research. To analyze the existing state and substantiate the areas of the irrigation and drainage sector development to ensure the sustainable agriculture in the face of a changing climate. Materials and methods of the research. In the work, a set of methods was used: analytical, expert evaluations, surveys, comparisons and analogues, experimental. Observation data from the state meteorological stations network were used to evaluate hydrothermal conditions and the data from the network of hydrological posts of Ukrhydrometcentre were used to evaluate the river condition. To assess the technical condition of the engineering infrastructure, methodological approaches were used in accordance with the requirements of the international and European standards and the normative documents currently in force in Ukraine. To identify the possible ways and mechanisms to restore the irrigation and drainage systems potential, the reasons of the existing state were analyzed and it was determined that the uncompleted land and economic reforms, imperfections in the existing legislation and state support mechanisms, especially in the sector management, caused the long-year underfunding of irrigation and drainage facilities operation and restoration and resulted in the crisis situation in the sector. Conclusions. Based on the study of the world experience and the carried out research, it was established that the restoration and development of irrigation and drainage in Ukraine are possible only along with the implementation of a legal and institutional reform to introduce decentralization, improvement of the existing legislation, modernization of irrigation and drainage systems through the development and implementation of investment projects for restoration and development of irrigation and drainage systems, creation of attractive investment environments, development and introduction of a financing mechanism to cover management, operation and maintenance costs based on a new tariff formation system, introduction of the scientific support and staffing system for the land reclamation sector. The basis for the deployment of irrigation and drainage restoration should be the "Irrigation and Drainage Strategy in Ukraine until 2030", and the appropriate plan of measures, formed on the basis of fundamentally new institutional, scientific, technical and technological, economic, organizational, social and environmental approaches, should become a tool for achieving the goals of the "Strategy ...". Successful implementation of the goals of irrigation and drainage restoration in Ukraine will create the conditions to sustainable and profitable agricultural production in the face of climate change, to restore irrigation on the area of about 1,0 to 1,2 mln. ha and drainage on the area of 1,0 mln. ha and to additionally get up to 10 mln. tons of grain, 8-10 mln. tons of fruit, berries and vegetables annually.

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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.