FORMATION OF THE WATER REGIME OF THE SOIL ON DRAINED LANDS IN MODERN CLIMATE CONDITIONS

Abstract

The results of analytical and field studies of the influence of modern climatic conditions on the formation of the soil water regime on drained lands are presented. It has been determined that an increase in air temperature and uneven distribution, changes in the nature, intensity, and structure of precipitation, and an increase in the number of cases of heavy rainfall, which are local during the warm period of the year, do not allow for the effective accumulation of moisture in the soil. The formation of new conditions for the cultivation of crops and changes in the directions of the use of drained lands requires expanding the functional tasks of drainage systems and improving the efficiency of water regulation on drained lands. Due to the discrepancy between the technological integrity embedded in the existing drainage systems at the stage of their design, the technical and technological capabilities of the systems, and the modern infrastructure of the users of drained lands, operational management of the technological processes of water regulation and maintenance of the optimal water regime of the soil is not ensured today. Studies at production sites on drainage systems typical for the drainage reclamation zone have established that carrying out a set of works to restore the channels of the open and collector-drainage network to design indicators, repairing and equipping hydraulic structures, the presence on the drainage systems of the possibility of water accumulation and the use of irrigation systems (drum-type sprinkler), made it possible to regulate the water regime of the soil and maintain humidity in the active soil layer within the limits close to optimal during the growing season. By regulating the groundwater level, the increase in the yield of crops was: spring wheat - by 19,8%, oats - by 26,5%, corn for grain - by 24,6%, and soybeans - by 48,0%. The cost of the increase in yield obtained by the water regime regulation during the study period averaged: spring wheat – 5,1 thousand UAH, oats – 4,8 thousand UAH, corn for grain – 12,9 thousand UAH, soybeans – 16,0 thousand UAH for 1 hectare. Information materials on the influence of modern climatic conditions on the formation of the soil water regime on reclaimed lands were obtained, which serve as the basis for the development of a methodology for substantiating the parameters for managing the soil water regime on reclaimed lands, taking into account the peculiarities of its formation under modern economic conditions and climate change.