STRUCTURE AND WATER STABILITY OF SOIL AGGREGATES OF TYPICAL CHERNOZEM UNDER SUNFLOWER IN THE LANDSCAPE CONDITIONS OF THE CENTRAL CHERNOZEM REGION
The aim of the study was to identify the optimal combination of organic fertilizers and basic tillage methods, contributing to the increase of erosion resistance of soils in the cultivation of sunflower on the slope of 3-5° North exposure, which will pull weight to the effective use of such lands in the landscape agricultural systems. As a result of research it was established that in the most erosion dangerous in Chernozem Region spring period the sites of different steepness didn't have essential differences in a share of agronomically valuable soil aggregates, but they defined the direction of influence of the soil tillage methods and organic fertilizers. During the sowing period the excellent structure of the top ten-centimeter layer of soil, having important value in relation to erosion, on the flatland site was formed due to using organic fertilizers under the tillage, no matter plowing or subsurface tillage (K=1,7 to 1,9), and on the slope plot - also due to organic fertilizers application, to a greater extent, green manure, with No-till (K=1,6-1,8). To improve the water stability of the soil structural aggregates on the flat area should also use deep loosening or plowing in combination with straw-litter compost (54%), in the slope relief - preference should be given to No-till (53%). The use of No-till was also due to the increase in water stability of the soil in the summer-autumn period (58%), the erosion danger of which is associated with heavy rainfall. Some positive effect of green manure at the time of sunflower harvesting was revealed if it had been embedded in the soil during its main tillage, on the slope of 3-5° - only with subsur-face tillage.