聚丙烯酰胺增加土壤降雨入渗减少侵蚀的模拟试验研究 Ⅰ.入渗

土壤 (特别是黄绵土 )在雨水作用下 ,表面会形成结皮 ,显著地降低降雨入渗率 ,聚丙烯酰胺 (PAM)能有效地抑制降雨过程中土壤结皮的形成 ,提高降雨入渗率。为了获得PAM使用量和覆盖率与入渗率之间的关系 ,进行了一系列的人工降雨模拟试验。试验采用了三个雨强 :5 0、1 0 0和 1 5 0mmh- 1,四个坡度 :8.74%、1 7.63 %、3 6.4%和 46.63 % ,及五种地表处理 :对照、秸秆覆盖和三个PAM覆盖率 (A、B和C) ,试验设三次重复。试验分Ⅰ、Ⅱ两个降雨阶段进行 ,第Ⅱ阶段在第Ⅰ阶段降雨结束土壤放置 2 4h后进行。分析建立了降雨入渗率与PAM的覆盖率间的相关关系 ,确定了PAM的覆盖率对降雨入渗的影响。

EFFECTS OF POLYACRYLAMIDE APPLICATION ON INFILTRATION AND SOIL EROSION UNDER SIMULATED RAINFALLS Ⅰ. INFILTRATION

Summary Surface crust of soil, especially Loess, formed under the impact of raindrops will significantly affect rain water infiltration rate. Polyacrylamide(PAM)can effectively prevent crust formation and improve soil structure and enhance soil permeability. To clearly relate PAM application with infiltration rate, experiments were conducted with rainfall simulator under laboratory conditions, at 3 different levels of rainfall intensity: 50 mm h -1 , 100 mm h -1 and 150 mm h -1 ; 4 slope gradients: 8.74%,17.63%, 36.4% and 46.63% and 5 surface treatments: control, straw coverage and three PAM coverages A, B, and C. Two rainstorms were simulated with a 24 h interval. Analyses were made to relate infiltration rates with PAM coverage and describe impacts of PAM application on infiltration.