FACTORS OF SLOPE SPRING RUNOFF ON GRAY FOREST SOILS IN THE CENTRAL FOREST-STEPPE

The results of long-term studies of several generations of scientists at the Novosilskaya zonal agroforestry and reclamation experimental station named after A.S. Kozmenko (a branch of the Federal Research Center of Agroecology of the Russian Academy of Sciences), initiated by Professor G.P. Surmach, were summarized and analyzed. The task was to assess the nature of the spring slope runoff formation and show the role of natural factors and agricultural activities. The methodological basis of the research was the method of runoff sites. As a result of a long (64 year long) study, a number of important dependencies and features of the runoff formation under different natural and climatic conditions were identified, as well as the influence of natural factors and agricultural activities on it (structure of sown areas, cultivation history, tillage methods, etc.). Scientific materials on the elements of the spring water balance give an idea of their patterns. It has been established that only three natural factors out of a large number of them have a significant impact on the slope spring runoff, i. e. the depth of soil freezing, snow reserves and humidity of the upper soil layer (down to 30 cm). Other factors almost do not affect the amount of runoff and they could be ignored in the process of calculation. The limiting levels of these three factors have been established, under which no runoff is formed. During 64 years of study, runoff was absent for 33 years, ranging from 1 to 146 mm in other years. Among anthropogenic factors, tillage methods and the state of agricultural backgrounds have a profound influence. The runoff regulatory importance of finching and the runoff forming role of perennial grasses and winter crops are discussed. On average, runoff from compacted arable land was 10 mm higher compared to loose chick; in some years the difference was significantly greater. The results of the study are necessary for the design of erosion-control adaptive landscape farming system.