基于数值模拟的土壤水渗漏对降雨条件的响应

Numerical Investigation on Response of Soil Water Percolation to Rainfall Condition

为了揭示土壤水渗漏对不同降雨条件的响应规律,采用数值模拟方法模拟了不同降雨情景下土壤水渗漏量的变化,并与实际降雨条件下现场观测结果进行比较。结果表明,土壤水的渗漏率与降雨强度关系密切;在保持总降雨量不变的前提下,低频率但高强度的降雨条件下土壤水渗漏总量明显高于高频率但低强度的降雨条件下的土壤水渗漏总量。土壤水瞬时下渗率与前期降雨事件有关,短时间内多次出现的降雨事件显著增大土壤水的下渗率。本研究可为减少土壤营养物质流失以及制定合理的农田水肥管理措施提供理论依据和科学指导。

Agricultural non-point source pollution caused by nitrogen loss from farmland soil has been becoming increasingly serious in recent years. This problem has attracted great attentions in the academic community. Soil nitrogen loss is highly relevant to the soil water leakage and percolation, and soil water percolation is further driven by the rainfall condition at the soil surface. colation to different rainfall conditions, this paper employed In order to reveal the response of soil water pera numerical model to simulate the soil water percolation rates under different rainfall scenarios. The model was first calibrated using field observed data. Results indicated that soil water percolation rate is highly correlated to the rainfall intensity. For the same total volume of rainfall, the volume of soil water percolation under rainfall events of low frequency and high intensity is greater than the volume under rainfall events of high frequency and low intensity. On the other hand, the percolation rate is relevant to the preceding rainfall events. Multiple rainfall events in a relatively short period will result in a peak percolation rate. The findings in this paper may provide theoretical basis and scientific evidence in formulating more rational management strategies of watering and fertilizing in an attempt to reduce the loss of soil nutrients.