Impact of conservation tillage on runoff, soil loss, and soil properties on acrisols and ferralsols in central Benin

Abstract

The present study is aimed at assessing the impact of different tillage practices and mulch input rates on soil erosion and soil properties in Central Benin. The experiment was carried out at two sites (Dan and Za-zounmè) using a randomized complete block design. The effect of three tillage practices: contour ridging (CR), slope ridging (SR), and no-tillage (NT) and four mulch input rates (0, 3, 5, and 7 t·ha−1) was investigated. The runoff, the soil, and nutrients losses were measured during the major rainy seasons of 2018 and 2019. Bulk density, gravimetric moisture, and water infiltration were collected in 2019. The effect of the interaction between tillage practices and mulch input rates was significant on runoff amount, runoff coefficient, soil loss, N, P, and K losses, and soil moisture. Over the investigated seasons, CR + 7M decreased runoff amount, runoff coefficient, soil loss, and N, P, and K losses by 100% compared to the treatments. NT was found to be effective in runoff and soil erosion controlling when combined with a mulch quantity greater than 3 t·ha−1, and NT + 5M and NT + 7M reduced the soil loss, respectively, by more than 30% compared to the farmer’s practice (SR + 0M) at both sites. Contour ridge treatments yielded more soil moisture than NT and slope ridge treatments. Whatever the tillage practice, the greatest gravimetric moisture was recorded on 5 and 7 t·ha−1 plots (i.e., CR + 7M, NT + 7M, and SR + 7M). This study provides decision makers with requisite information for effective soil erosion management in Benin where mechanization aids are limited.