Simulated Runoff and Erosion on Soils from Wheat Agroecosystems with Different Water Management Systems, Iran.

In developing countries, the demand for food has increased with significant increases in population. Greater demands are therefore being placed on the agricultural sector to increase production. This has led to increased soil erosion, especially in arid and semi-arid regions. The aim of this study was to simulate runoff and erosion on soils of three different wheat agroecosystems (rainfed farming, traditional irrigation, and industrial irrigation systems). The effect of variations in soil texture, slopes (1, 3 and 5%) and rainfall intensity (10, 25 and 40 mm h⁻¹) on runoff volume, runoff coefficient, sediment concentrations, and sediment loss (soil erosion) were recorded for soils from each management system. Soil chemical properties (pH, EC) and organic matter were not significantly related to soil erosion. Analysis of variance showed significant differences in soil erosion and runoff coefficients when slopes were increased from 1 to 5 percent. The highest soil erosion was recorded on a slope of 5% with a rainfall intensity of 40 mm h⁻¹, and the lowest on a slope of 1% with a rainfall intensity of 10 mm h⁻¹. Of the three management systems, the highest runoff volume, runoff coefficient, sediment concentration and soil erosion occurred on soils from the traditional irrigation treatment, with a soil texture of sandy loam, slopes of 5% and rainfall intensity of 40 mm h⁻¹. Results of the study indicated that the influence of slope and rainfall intensity on runoff volume, runoff coefficient, sediment concentration and soil erosion varies with soil texture and agroecosystem. These results can be usefully applied to agricultural land use planning and water management systems for reducing soil erosion at regional and on-farm levels. [ABSTRACT FROM AUTHOR]