中文摘要：

中性多聚糖（Jag S）是一种新型高聚物,研究该高聚物对黄土坡面降雨入渗的影响可对采用土壤侵蚀化学调控技术措施防治黄土坡面土壤侵蚀提供新的理论基础。通过人工模拟降雨试验,研究不同雨强（1.0、1.5、2.0 mm min-1）,不同坡度（10°、15°、20°）条件下,坡面降雨入渗及产流时间与喷施不同剂量（1、3、5 g m-2）Jag S之间的关系。结果表明：在不同坡度不同雨强下,与裸露坡面相比,喷施3种剂量的高分子化学材料Jag S均减少了前期降雨入渗率,但1及3 g m-2剂量Jag S处理能够明显提高黄土坡面入渗性能,减缓入渗在整个降雨过程的下降趋势,提高稳渗率,强化入渗效应均值分别为21.53%及9.17%,大剂量（5 g m-2）Jag S反而降低了土壤入渗性能（小雨强下除外）。喷施不同剂量Jag S的坡面其产流开始时间差异很小,但均早于裸露坡面,且表现为Jag S喷施剂量越大,坡面越早产流,大坡度大剂量对降雨产流时间影响较大。三个剂量对应产流时间提前百分比均值分别为47.26%、50.47%及66.28%。总之,Jag S在一定程度上能改善黄土坡面土壤结构,提高黄土坡面降雨入渗性能,从而降低土壤侵蚀,为采用高聚物进行水土保持提供了科学依据。

英文摘要：

[Objective ] The technology of using chemicals to control soil erosion is mainly implemented through spraying high molecular compounds over on the surface soil layer to improve its soil structure, to enhance stability of its soil aggregates, to prevent dispersion of its clays and hence to increase rain water infiltration rate and eventually to control surface runoff and soil erosion. Jag S is a kind of neutral polysaccharide and a new type of high polymer. This study on effect of the use of this high polymer on rainwater infiltration rate in loess slopes is intended to lay down a new theoretic basis for applying the technology of using chemicals to control soil erosion to the Loess Plateau in arid and semi-arid regions for erosion control and water conservation. Control of soil erosion with chemicals is a new method, which is developed on the basis of the modern chemical industry and different from the traditional soil and water conservation methods. [ Method] An indoor experiment was conducted in the Rainfall Simulation Hall at the State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau at the Institute of Soil and Water Conservation. A rainfall simulator system with side-sprinklers was used to simulate rainfall events different in intensity ranging from 0.5 to 3.5 mm min^-1. The sprinklers were 16 m high above the experimental field, providing simulated rainfall events over 80% in uniformity and raindrops 0.25 to 0.375 mm in diameter, when a rainfall event was set at 1 - 2 mm min^-1 in rainfall intensity. Kinetic energy of the raindrops striking at surface soil of the field ranged from 365 to 847 J h-1 m^-2. The indoor simulated rainfall experiment was designed to explore relationships of rain water infiltration rate and initiation time of runoff with dosage （ 1, 3 and 5 g m^-2 ） of Jag S used relative to slope gradient （ 10°, 15° and 20°） and rainfall intensity （ 1.0, 1.5 and 2.0 mm min^-1 ） . [Result] Results show that compared with the CK slope, all the slopes sprayed