Soil losses in the State of Rondônia, Brazil

ABSTRACT: In the state of Rondônia, deforestation, and inadequate soil use and management have intensified the water erosion process, causing degradation of agricultural land. Modeling is a tool that can assist in the adoption of targeted and effective measures for soil and water conservation in the region. In this context, the objective of the research was to model soil losses due to water erosion in the state of Rondônia using the Revised Universal Soil Loss Equation (RUSLE). The parameters related to rain erosivity, relief, erodibility, and soil cover, as well as the conservation practices of the state of Rondônia, were considered. The modeling steps were performed with the aid of the Geographic Information System. Results were validated with data of total sediments transported with water discharge. The estimated total soil loss was about 605 million tons per year, corresponding to an average loss of 22.50 Mg ha-1 year-1. In 19% of the state, the erosion rate was higher than the soil loss tolerance(T), and these areas should be prioritized for adopting measures to mitigate the erosion process. The RUSLE underestimated the generation of sediments at 0.56 Mg ha-1 year-1, which corresponds to an error of 18.60%. Results obtained can assist in the development of different soil use and management scenarios and provide options for policymakers to encourage soil conservation in the state of Rondônia.

摘要：在朗多尼亚州，由于森林砍伐、土壤使用与管理不当，加剧了水土流失过程，导致农业用地退化。建模是一种辅助实施该地区土壤与水资源保护针对性有效措施的工具。在此背景下，本研究旨在运用修正的通用土壤侵蚀方程（RUSLE）对朗多尼亚州的土壤侵蚀损失进行建模。考虑了与降雨侵蚀力、地形、侵蚀性和土壤覆盖相关的参数，以及朗多尼亚州的保育措施。建模步骤在地理信息系统辅助下进行。结果通过总泥沙输移量数据进行了验证。估算的总土壤侵蚀量约为每年6.05亿吨，相当于平均损失22.50 Mg ha-1年-1。在该州19%的地区，侵蚀速率高于土壤侵蚀容忍度（T），这些地区应优先采取缓解侵蚀过程的措施。RUSLE低估了0.56 Mg ha-1年-1的泥沙生成量，误差率为18.60%。所得结果有助于不同土壤利用和管理情景的发展，并为政策制定者提供鼓励朗多尼亚州土壤保育的选项。