Effects of Soil Physical Properties and Slope Gradient on the Growth Performance of Hybrid Maize (ADF Ruby)

Abstract

The expansion of corn cultivation to dryland areas in the highlands increases the risk of soil degradation due to slope gradients, which can alter soil physical properties, increase erosion, and reduce crop productivity. This study aims to analyze the effect of slope gradient on the physical and chemical properties of soil, erosion potential, and the growth and yield of the hybrid corn (Zea mays L.) variety ADF Ruby in the highlands of Bima Regency, Indonesia. The study employed a field survey method across three slope gradient classes (8–15%, 15–25%, and >25%). Erosion potential was predicted using the Universal Soil Loss Equation (USLE), while data were analyzed using ANOVA, Pearson’s correlation, and simple linear regression. The results showed that an increase in slope gradient did not significantly alter soil particle density, bulk density, and porosity, but it increased soil permeability from 3.85 to 9.03 cm h⁻¹ and predicted soil loss from 83 to 317 metric tons ha⁻¹ year⁻¹. The highest maize growth and yield were obtained on slopes of 8–15%, while soil permeability was very strongly negatively correlated with dry kernel weight (r = −0.98; R² = 0.89). The results of this study indicate that the effect of slope on corn productivity is mediated by changes in soil hydrological characteristics and an increased risk of erosion; therefore, soil and water conservation are key to the sustainable management of sloping dryland.