PROBLEMS AND DIRECTIONS FOR IMPROVING THE METHODOLOGY FOR ASSESSING THE IMPACT OF CLIMATE RISKS ON THE SUSTAINABILITY OF MELIORATIVE AGRICULTURE

Global climate change drives aridization and instability of soil-moisture conditions, which threatens sustainable development in agriculture and creates preconditions for accounting for these changes in the design of irrigation and drainage (land reclamation) systems and their operating regimes. Existing methods for designing irrigation and drainage often do not account for current climate trends (seasonal shifts, increased duration of rainless periods, changes in temperature regime), which creates a need for their systematic improvement. The article presents an approach to assessing the impact of climate risks on irrigated agriculture that integrates up-to-date indicators (moisture-supply deficit, reference evapotranspiration, crop coefficients, soil water-holding capacity and field capacity, the frequency and intensity of droughts, heat waves and precipitation intensity) with scenario analysis to forecast different moisture regimes under expected climate conditions. The concept of a methodology adapted to the regional diversity of Ukraine is outlined. For testing, pilot regions with contrasting climate-soil characteristics are proposed: the arid South, the moderately arid Center (periodic temperature stress, high inter-annual variability of precipitation), and the West, which is excessively humid in spring and slightly arid in summer (risks of waterlogging, the need for effective drainage at the beginning of the growing season and additional moisture supply during the rest of the period). A monitoring and validation program is proposed, including regular collection of meteorological data (daily temperatures, precipitation, radiation, wind, humidity), biometric indicators of plant growth and development (development stages, leaf-area indices, actual yield), soil characteristics (moisture, structure, nutrient content), as well as performance indicators of irrigation and drainage networks. Based on these data, crop coefficients and modelling parameters are refined, which makes it possible to perform hourly–daily calculations of water deficit, to develop adaptive irrigation and moisture-supply schedules, and to test SSP-based climate scenarios. The use of modern digital and automated tools (local weather stations, soil-moisture sensors, etc.) forms the basis for the digitalization of irrigation and water-regulation management in line with impact indicators. The improved methodology will make it possible to increase water-use efficiency in existing reclamation systems, incorporate updated climate parameters into new designs, reduce the vulnerability of agro-systems to droughts and other extreme weather events, minimize yield losses, and ensure production stability under climate change. An additional advantage is the possibility of ranking investment options according to economic efficiency indicators.