Estimates of soil losses by the erosion potential method in tropical latosols

ABSTRACT Water erosion is one of the main problems faced in coffee cultivation, as it promotes environmental degradation and crop yield decrease. Erosion estimates support the planning of conservation management practices and allowing determining the rates of soil losses. Thus, the objective of this paper was to estimate the soil loss by water erosion using the Erosion Potential Method in a sub-basin predominantly covered by coffee cultivation and then to compare the results with the Soil Loss Tolerance limits. The study area is the Coroado Stream Sub-basin, located at Alfenas Municipality, south of Minas Gerais, Brazil. The sub-basin presented an Erosion Coefficient of 0.272, indicating a predominance of low-intensity erosion. The total soil loss estimate was 1,772.01 Mg year-1 with an estimated average of 1.74 Mg ha-1 year-1. Soil Loss Tolerance limits range from 4.75 to 7.26 Mg ha-1 year-1 and, according to the Erosion Potential Method, only 1.0% of the sub-basin presented losses above the limits. The areas with the highest slopes and bare soil concentrated the highest losses rates and should be prioritized in the adoption of mitigation measures. The Erosion Potential Method estimated soil losses in tropical edaphoclimatic conditions in a fast, efficiently and at low cost, supporting the adoption of conservation management practices.

摘要 水蚀是咖啡种植面临的主要问题之一，其会加剧环境退化并导致作物产量下降。侵蚀估算可为水土保持管理措施的规划提供科学支撑，同时可用于确定土壤流失速率。为此，本研究以巴西米纳斯吉拉斯州（Minas Gerais）南部阿尔费纳斯市（Alfenas Municipality）的科罗阿多溪子流域（Coroado Stream Sub-basin）为研究对象，采用侵蚀潜力法（Erosion Potential Method）估算该以咖啡种植为主要土地覆被类型的子流域的水蚀土壤流失量，并将估算结果与土壤流失容许量（Soil Loss Tolerance）限值进行对比。
该子流域的侵蚀系数为0.272，表明其以低强度侵蚀为主。总土壤流失估算量为1772.01 Mg·年⁻¹，平均土壤流失量为1.74 Mg·公顷⁻¹·年⁻¹。研究区内土壤流失容许量限值范围为4.75至7.26 Mg·公顷⁻¹·年⁻¹，依据侵蚀潜力法的计算结果，仅有1.0%的子流域面积出现了超出容许限值的土壤流失。
坡度较高且土壤裸露的区域集中了最高的流失速率，此类区域应优先纳入水土保持减缓措施的实施范围。
本研究采用侵蚀潜力法可快速、高效且低成本地估算热带土壤气候条件下的土壤流失量，可为水土保持管理措施的落地提供科学依据。