TECHNICAL IMPROVEMENT OF THE DESIGN OF RICE IRRIGATION SYSTEMS

Abstract

The article presents the results of many years of research aimed at technical improvement and efficiency of rice irrigation systems in the Southern region of Ukraine. The aim of the study was to determine the technical, economic and environmental reclamation efficiency in the long-term operation of the world's first in irrigation science and practice of rice irrigation system with reverse cycle of water use – closed check irrigation system (ZCHZS-M) design of a famous domestic scientist. Makovsky V.Y. An urgent problem in rice cultivation in the south of Ukraine is that this technological process requires significant amounts of irrigation water. Significant water supply raises the issue of large volumes of unproductive technological discharges of water (which may exceed 50% of water supply), which, in turn, negatively affects the environmental situation in the region and the economic efficiency of the RZS. The scheme of operation of ZCHZS-M differs from the known schemes of RZS that in order to reduce capital and energy costs, precinct and distribution pipelines, combining the functions of supply and discharge of water from two adjacent areas, are eventually connected by a pumping station and drainage. the collector network performs the function of drainage only. Research has identified the main technological indicators of ZCHZS-M in the operational period (production mode): irrigation rates of rice – 13–14 thousand m3/ha, related crops – 2,4 thousand m3/ha; drainage runoff – 2,5–3,0 thousand m3/ha; the regime of groundwater in the non-vegetation period is semi-hydromorphic, in the vegetation period it is hydromorphic, which is characteristic of rice irrigation systems with a favorable ecological and reclamation condition. ZCHZS-M provides a reduction in the level of groundwater at the beginning of the growing season to a depth of 1,8–2,2 m, relatively stable mineralization of groundwater 2,1–2,6 g/dm3 and the type of their chemical composition – sulfate-bicarbonate, magnesium – sodium. The accumulation of salt reserves in the aeration zone for the period 1990–2021 has not been determined. The total salinity of the soils of the aeration zone did not exceed 0,2%, the type of salinity of chloride-sulfate soils did not change significantly. ZCHZS-M provides operational management of ecological and reclamation regime of agrolandscapes, first of all, soils. In the course of many years of production research, the technology of operation of ZCHZS-M was tested. The established high level of technical, economic and ecological-ameliorative efficiency of ZCHZS-M allows to recommend it at reconstruction of rice irrigation systems on poorly drained and drainless lands of coastal lowlands in the Southern region of Ukraine.