Pedo-hydrological and sediment responses to simulated rainfall on soils of the Konya uplands (Turkey)

Abstract

Microplot experiments using a portable rainfall simulator were carried out in April 1992 on 15 Turkish soils with textures ranging from clay loam to loamy clay and slopes from 3° to 12°. In order to determine the effects of a change in land use on infiltration and erosion, pairs of sites with soils developed on identical parent material were chosen. Several physical and chemical properties of the soil were determined and related by regression analysis to various soil loss and infiltration variables. The regression equations showed that plant cover, and therefore the type of land use, was the most important factor. Plant cover influenced various important soil characteristics which determine the infiltration behaviour of the soil, namely humus, root content and macropore distribution. The slope, physical, textural, and chemical properties of the soils and aggregate stability were only of secondary importance. The shear vane test was not well-suited for measuring the surface properties of these soils, which were initially cohesionless and consisted of loose aggregates. Erosion damage mapping showed high rill erosion rates after snow melting and spring rainfalls on tilled and seedbed sites, up and down hill culture, slopes with gradients > 8 degrees, and on northwest exposed slopes. Results of the microplot tests and erosion damage mapping were in general qualitative agreement. On the catchment scale, the variations of the mesoclimate due to exposure and altitude became important.