Soil erosion responses of cropland uses in contrasting slope in the Abay basin, Ethiopia

Abstract

Cultivated land is the primary source of runoff and soil loss in a watershed. Quantifying the soil erosion response of dominant cereal crops at different slope gradients is vital to sustainable land use, crop management, and conservation options. This study evaluated the runoff loss (Ro), runoff coefficient (RoC), and soil loss (SL) responses of teff (Eragrostis tef), maize (Zea mays), and wheat (Triticum aestivum) cropland use under different slope conditions. During 2020 and 2021, 18 experimental erosion plots (3 m × 10 m) having 3 crops × 3 slope gradients (8%, 18%, and 32%) with two replicates were installed. Soil loss and runoff analysis were made and the significance variation among land uses and slopes was tested using ANOVA. On average, the highest Ro is recorded from teff land use (700 mm) followed by wheat (651.2 mm), and maize (570 mm) land uses. The Ro generated from the teff crop land use exceeds 18.5% and 6.9% compared to maize and wheat crop land uses (P < 0.05). The lower proportion of the rainfall was converted to runoff (RoC = 38%) under the maize crop land use, however, nearly half of the rainfall (RoC = 46.6%) became runoff in the teff crop. The average (three slope gradients) rate of SL in teff, wheat, and maize crop land uses was found to be 54.86, 45.61, and 38.27 t ha⁻¹ year⁻¹, respectively. Although the result shows high soil erosion in all cereal crops, cultivation of the teff crop in general and on steep slopes in particular leads to a high Ro and SL. Therefore, sustainable land management practice and setting land use policy are recommended, particularly for teff cultivation.