Generalization of scientific experience and modern aspects of its use to ensure the effective functioning of water-regulating systems in the Left Bank Forest Steppe of Ukraine

The experience of agricultural production on drained lands indicates that the existing scientific justification for land reclamation does not meet the requirements of today. This also applies to the use of drained lands of the Left Bank Forest-Steppe. The goal of the research is to generalize many-year scientific research (on the drainage-irrigation system "Romen") and determine the modern aspects of its use to ensure the effective functioning of water-regulating systems in the Left Bank Forest-Steppe in a changing climate. To summarize, we used the results of many-year research for the period of 1935–2019, which were obtained on the drainage-irrigation system "Romen". The research methods are based on systematic analysis and knowledge generalization on long-term research in the area of the Left Bank Forest-Steppe. It was established that in the conditions of the Left-Bank Forest-Steppe (on the drainage-irrigation system "Romen") a considerable number of scientific developments on the technologies of crop cultivation on the drained lands was obtained, the most productive cultivars of crops were selected and optimum norms of fertilizers for their application were calculated. The methods of basic tillage were studied taking into account the cultivation degree of soils, new designs of reclamation systems were developed (combined water-regulating systems with inclined and low-slope drains and water control units; local contour-water storage systems), which were tested in the production conditions and resource-saving water regulation technology, which is based on the use of small irrigation rates. For today, to scientifically ensure the effective functioning of water- regulating systems and the use of drained lands in the Left Bank Forest-Steppe in a changing climate, it is important to use the experience gained on agronomic measures for growing crops on drained lands, improving water supply of reclamation systems (application of contour water-absorbing constructions made of local filtration materials), resource-saving technologies of water regime regulation, which are based on applying small irrigation rates. Currently, in the context of climate change, which has led to the deterioration of water supply conditions on water-regulating systems, the research is underway to improve the efficiency of water-regulating systems and the use of drained lands, taking into account the features of their agricultural use. The technology of accumulation of water and drainage runoff in the accumulating tank was developed. The results of its approbation showed that in the conditions of climate change, growing deficit of water resources it is possible to provide effective water regulation on drained lands by creating reserve water volumes in the reclaimed areas and increase the yield of crops. According to the results of regional experimental studies on the cultivation of promising and highly productive fodder crops (barnyard grass, amaranth and fodder beans) a technology for growing them on different types of drained soils was developed, which is based on optimal water regulation and takes into account the supply of essential nutrients, the degree of soil acidity and modern climate change.