植被格局对土壤入渗和水沙过程影响的模拟试验研究

合理的植被格局能够提高土壤入渗性能和抗冲性，有效阻蚀减沙，平衡土壤保持与土壤水分保蓄二者关系，进而促进生态环境的改善。基于径流小区人工模拟降雨，研究了多种植被格局生物量密度（0、50%、100%）和分布方式（坡上分布、坡下分布、均匀分布）的土壤入渗、产流、产沙特征以及土壤储水量变化。结果表明：使用Philip模型、Kostiakov模型、Horton模型模拟坡面入渗过程，Horton模型的拟合结果最优。不同植被格局产流率的变化趋势基本一致，大体可分为两个阶段：初期阶段迅速增长，中后期阶段增长变缓并逐渐趋于稳定状态。产沙率的变化趋势随植被格局的不同而略有差异。相较于产流过程，产沙过程变化剧烈、规律性差。总体而言，降低生物量密度能够增加降雨期间的径流量（从19.21 mm到25.44-38.09 mm再到51.79 mm）和侵蚀量（从118.97 g/m²到237.57-597.90 g/m²再到1400.29 g/m²），土壤水分得到更好的保蓄。从植被分布方式的角度来看，均匀分布的植被格局有利于更好地控制土壤侵蚀和径流，却促进了土壤水分的消耗。坡下分布的植被格局，例如植被过滤带的形式，能够最好地同时控制水土流失和土壤耗水。权衡考虑水土流失防治与土壤水分消耗，建议采用适宜密度（本研究为110 g/m²）且集中分布在出口附近的植被格局。

Simulation experiment on the influence of vegetation pattern on soil infiltration and water and sediment process

Reasonable vegetation pattern can improve soil infiltration performance and erosion resistance, effectively reduce runoff and sediment yield, balance the relationship between soil erosion prevention and soil water conservation, and then promote the improvement of the ecological environment. In the plot scale, based on artificial simulated rainfall, the soil infiltration, runoff, sediment production characteristics and soil storage of various vegetation patterns biomass density (0, 50%, 100%) and distribution methods (concentrated distribution on the upper of the slope, concentrated distribution on the lower of the slope, uniform distribution) were studied. The results show that among the Philip model, Kostiakov model, and Horton model used to simulate the slope infiltration process, the Horton model has the best fitting results. The change trend of runoff rate of different vegetation patterns is basically the same, which can be roughly divided into two stages: rapid growth in the initial stage, slower growth in the middle and later stages and gradually tending to a stable state. The variation trend of sediment yield varies slightly with the vegetation pattern. Compared with the runoff process, the sediment production process changes drastically and has poor regularity. Overall, reducing biomass density can increase runoff (from 19.21 mm to 25.44-38.09 mm to 51.79 mm) and erosion (from 118.97 g/m² to 237.57-597.90 g/m² to 1400.29 g/m²), as well as soil moisture is better preserved. The concentrated vegetation pattern under the slope, such as the form of vegetation filter belt, can best control both soil erosion and soil water consumption. Comprehensively considering soil erosion prevention and soil water consumption, it is recommended to use a vegetation pattern with appropriate density (110 g/m² in this study) and concentrated distribution near the exit.