Water erosion poses a major threat to food security and the sustainability of agricultural land. It leads to the uprooting, transport, and sedimentation of eroded material, thus contributing to soil degradation. This study aims to assess the risk of erosion in the N'Zi watershed in M'Bahiakro and to provide useful tools for agricultural soil conservation. The analysis is based on the Universal Soil Loss Equation (USLE), integrated with satellite remote sensing and geographic information systems (GIS) used for modeling the main factors involved in erosive phenomena. Monthly rainfall, soil map, a 30 m digital elevation model derived from a topographic map, a land cover map produced from the supervised classification of a Land Sat image, as well as land use types and steep slope were used to determine the USLE factor values. The results reveal two main classes of erosion risk: moderate (5 to 10 t/ha/year) and high (10 to 50 t/ha/year). In 1986, moderate losses were located in the north of the basin (Tafiré, Niakara, Katiola), while the highest losses occurred in the areas of Satama Sokora, Bouaké and M’Bahiakro. The average soil loss was 9.40 t/ha/year, with a maximum of 356.61 t/ha/year. In 2002, high erosion extended to the entire basin, with the exception of the northern area (Tafiré), where losses remained moderate. The average loss reached 10.69 t/ha/year, with a maximum of 361.72 t/ha/year. In 2023, erosion is moderate in the north and south (Satama Sokora, M’Bahiakro), while the center and west of the basin are at high risk. The average loss is 6.41 t/ha/year, and the maximum recorded is 205.52 t/ha/year, a significant decrease compared to previous years. These results highlight the evolution of the erosion phenomenon and underline the urgency of implementing appropriate conservation strategies. The implementation of sustainable agricultural practices would reduce soil loss and improve agricultural land management. In addition, the method used could be applied to other watersheds to optimize soil conservation and natural resource management.

Water Erosion, Soil Loss, N'Zi Watershed, USLE Model, Water Resources, M’Bahiakro, Côte d’Ivoire