SOIL COVER IS STRATEGIC TO REMEDY EROSION IN SANDY SOILS

ABSTRACT Sandy-textured soils are naturally more vulnerable to the erosion process and their exploitation, although possible, is often performed inappropriately, favoring its degradation. In this context, this study aimed to classify the rainfall erosivity in a region of sandy soils to identify critical situations of soil and water loss and also correlate it with rainfall data to assess whether there is temporal dependence of this variable using geostatistical techniques. The potential for alternative and sustainable production systems to be used in regions with sandy soils was also analyzed. Historical data of precipitation in the study region were analyzed to determine the average monthly and annual erosivity indices, which were classified and its temporal dependence was assessed by applying geostatistics. NDVI data from satellite images were used to investigate the soil cover pattern in different production systems. Geostatistics was adequate for the analysis of rainfall erosivity, which showed moderate to strong temporal dependence. It was classified between strong and very strong and was highly dependent on precipitation, with events of higher erosion potential between October and March in the studied region. The vicious circle of degradation of sandy soils, such as those of the Bolsão region of Mato Grosso do Sul, Brazil, can be modified by adopting alternative and sustainable production systems that value the maximization of soil cover.摘要：砂质土壤天然更易遭受侵蚀作用，尽管其可被开发利用，但开发方式往往失当，反而加剧土壤退化。在此背景下，本研究旨在对某砂质土壤区域的降雨侵蚀力进行分级，以识别水土流失的临界状况；同时结合降雨数据，采用地质统计学方法评估该变量是否存在时间依赖性。此外，本研究还分析了适用于砂质土壤区域的替代型可持续生产体系的应用潜力。本研究对研究区域的历史降水数据进行分析，以计算月均与年均侵蚀力指数，随后对指数进行分级，并通过地质统计学方法评估其时间依赖性。本研究利用卫星影像获取的归一化植被指数（NDVI, Normalized Difference Vegetation Index）数据，探究不同生产体系下的土壤覆盖格局。结果显示，地质统计学方法适用于降雨侵蚀力的分析，该变量呈现中等至强的时间依赖性。该区域的降雨侵蚀力被划分为强至极强等级，且高度依赖降水，研究区域内侵蚀潜力较高的降雨事件多集中于10月至次年3月。巴西南马托格罗索州博尔桑（Bolsão）区域的砂质土壤退化恶性循环，可通过采用重视土壤覆盖最大化的替代型可持续生产体系加以改善。