A temporal and spatial simulation of the sediment input in an agricultural basin in the municipality of Fernandópolis, São Paulo, Brazil

ABSTRACT The characterization of sediment input in watersheds is an important tool for projects that support soil conservation and watershed management. A spatial and temporal analysis of the sediment input in an agricultural watershed tributary of Santa Rita River was performed by means of a geoprocessing simulation in the municipality of Fernandópolis, São Paulo, Brazil. In order to accomplish this, there was a simulation of sediment delivery using the Modified Universal Soil Loss Equation (MUSLE) method for basins, from October 2012 to September 2013. There was a total of 433.87 t of sediments contributed in the period evaluated, resulting in an average soil loss of 3,635 t.ha-1.yr-1. The period with the greatest amount of sediment input was from December 2012 to March 2013. 65.1% of all the sediments were produced at that time. In the most critical month of sediment input, February 2013, about 15% of the total basin area showed sediment contributions ranging from 2 to 15 t.ha-1.yr-1. Sugarcane contributed the most sediment, accounting for 92% of the total, and an average of 6,343 t.ha-1.yr-1.

摘要 流域沉积物输入特征表征是支撑土壤侵蚀防治与流域管理相关项目的重要技术手段。本研究以巴西圣保罗州费尔南多波利斯市境内圣丽塔河支流的农业流域为研究对象，通过地理过程模拟方法开展沉积物输入的时空特征分析。为完成该分析，研究采用修正通用土壤流失方程（Modified Universal Soil Loss Equation，MUSLE）对流域产沙量进行模拟，模拟时段为2012年10月至2013年9月。评估时段内流域总产沙量为433.87吨，流域年均土壤侵蚀模数为3635 t·ha⁻¹·yr⁻¹。产沙量最高的时段为2012年12月至2013年3月，该时段产沙量占总产沙量的65.1%。在产沙量最高的月份——2013年2月，流域内约15%的区域产沙量介于2~15 t·ha⁻¹·yr⁻¹之间。其中甘蔗种植用地贡献的沉积物占比最高，达总产沙量的92%，对应平均产沙模数为6343 t·ha⁻¹·yr⁻¹。