The purpose of research is the study of surface melt water runoff formation from the loose and compacted arable land, depending on tillage methods on ordinary chernozems in Rostov region. Conducting field research, analysis of soil and water samples, monitoring and recording were carried out on south-facing waterrdivide type of agricultural landscape with a soil surface gradient of 1.5–2.0 % in accordance with the procedures for the development of adaptive-landscape farming systems, the surface runoff recording and soil loss by water erosion study. Field studies of surface runoff lasted from 1970 to 2015. Methodology studies have provided observations on the stationary runoff areas by size 270 × 30 m to determine the melt and rain water runoff in triplicate. The influence of water reserves in snow before snowmelt + rainfall during the melting, soil freezing depth, topsoil moisture (0–30 cm), water permeability on snowmelt runoff indicators was studied in 2000–2015 on the same sites. Studies have allowed to established that snowmelt runoff from loose arable land (fall plowing, plowing) is observed every three years (probability 30 %, yrs), with a compacted arable land (winter wheat and perennial grass planting) – two times in three years (probability 65 %, yrs). Water reserves in snow + rain precipitation during melting, are on average 43.4 mm on loose arable land and 48.6 mm on compacted arable land. The average flow is consequently 7.3 and 16.3 mm, ie runoff increases by 2.2 times on compacted arable land in comparison with loose arable land, where moisture gets absorbed into soil to a greater extent. The aquired equations and the dependence of the melt water runoff and runoff coefficient on water reserves in the snow, the water soil permeability during snowmelting, the top layer moisture and depth of soil freezing can be used for program development and simulation of the processes of runoff and soil erosion by meltwater.
Keywords: runoff, runoff coefficient, surface runoff, snowmelt water, compacted arable land, loose arable land, fall plowing.
