Assessing the Interaction between Water Erosion and SOC Storage in a Small Mexican Watershed

Water erosion is a significant issue that impacts a substantial portion of Mexico. The purpose of this study is to establish a connection between soil erosion and soil organic carbon (SOC) reserves. This work was conducted within a small watershed in the Mixteca Alta region of Oaxaca, in order to examine the correlation between erosion intensity, determined via the revised universal soil loss equation (RUSLE), and SOC storage, calculated using spatial models. The results reveal erosion values between 0.19 and 266.99 Mg ha-1 year-1, with 305 693 t of erosion in the micro-watershed. The erosion patterns are closely linked to land use categories. The average SOC values (​​in Mg ha-1) were associated with erosion, which was reclassified as null (31.79), light (22.36), moderate (16.19), and high (5.22). Kendall's tau coefficient showed a negative correlation of -0.39 between erosion and SOC. This inverse relationship can be attributed to the influence of erosive processes on the transport and exposure of SOC, the later replacement of carbon in the vegetation, and a reduced decomposition in deposition areas. Therefore, conservation practices, particularly terracing, have the potential to improve carbon storage.