Erosion rates depending on slope and exposition of cropped chestnut soils

Abstract

The surface runoff erosion of dark and light chestnut soils (Kastanozems) in the Ile Alatau foothills in the Zhambyl/Karasai administrative area and in the western part of Chemolgan near Almaty/Kazakhstan was analysed for use in devising adaptive landscape agricultural systems. 1:25,000 scale maps were modelled by combining geo-information techniques, field work and laboratory analytics. Rain and snowmelt activity depending on exposure on southern and northern slopes of agricultural land was differentiated. Single parameters were measured as snowmelt erosion and water erosion; a runoff coefficient was then calculated to determine the level of soil erosion from the intensity of the erosion processes. The results reveal that dark and light chestnut soils on northern slopes are more resistant to water erosion than those on southern slopes. It was also found that soil erosion processes induced by erosive rain are more intensive than snowmelt erosion. For chestnut soils, water erosion rates ranged from 1.4 to 30.8 t/ha induced by rainfall and from 0.7 to 3.5 t/ha induced by snowmelt, depending on slope inclination and exposure. Greater erosion was detected on southern slopes. No clear differentiation was found when comparing the erosion rates of dark and light chestnut soils.