Water need formation on the drained lands in the variable climatic, agricultural and ameliorative conditions

Relevance of research. At both global and regional levels, climate change has become an indisputable fact, the presence of which has posed to humanity the challenge of solving a number of extremely important and complex tasks related to the development and implementation of a strategy for their practical continued existence. Data base on evaporation and water needs for agricultural crops in the different periods of their growing, depending on the climatic conditions, are the basis for the development of design and formation of operational regimes of water regulation carried out by justifying the necessary methods of water regulation, types, structures and modes of operation of hydro-reclamation systems and calculation of their parameters. Aim of the study is to estimate the changes in water needs during crop cultivation on the drained lands of the Western Polissya in Ukraine in the variable climatic, agricultural and ameliorative conditions for the substantiation of appropriate adaptive decisions to it. To achieve this goal, the authors evaluated the weather and climate conditions in the Western Polissya in Ukraine and calculated the evaporation in the studied conditions, planned and carried out a large-scale computer experiment, based on a complex of predictive-simulation models concerning the basic regimes and technological variables of the hydro-reclamation system parameters, climate conditions, water regime, water regulation technologies and the productivity of drained lands for the schematized natural, agricultural and ameliorative conditions. Research methods. The research methods were based on the application of system theory along with the systematic approach, system analysis and modeling oriented on widespread use of computers and related software in developing modern approaches to the substantiation of technical and technological solutions for water regulation on the drained lands in the conditions of climate change. The object of the study is the drainage system “Birky” in Rivne region, typical for the region in relation to the natural land reclamation conditions.   Results of the study and the main conclusions. It was established the needs for additional irrigation of cultivated crops on the drained lands of the Western Polissya in Ukraine in the current weather and climatic conditions. Based on the long-term forecast the vegetative values of the total evaporation and the formation of water needs for the drained lands in the variable climatic, agricultural land reclamation conditions were determined. The technological efficiency of different technologies of the irrigation on the drained lands was evaluated.  This approach to the estimation of changes in water needs during crop cultivation in the variable climatic, agricultural and ameliorative conditions allows determining the best technology of water regulation for growing a particular crop under the studied conditions in terms of the most rational use of water resources and the efficiency of system functioning. Prospects. The obtained results can be effectively used for justification of regime and technological decisions in the projects of construction and reconstruction of hydro-reclamation systems of the Western Polissya in Ukraine in the variable climate conditions and developing hydro-technical adaptive measures to the predicted climate change in the region.