红壤坡地降雨入渗、产流及土壤水分分配规律研究

选取农作区和荒草区两个不同利用模式下的红壤坡地，研究了降雨的入渗、产流及对土壤水分分布的影响。结果表明：（1）农作区和荒草区的径流系数都随着年限的延长而降低并达到稳定。降雨量成为影响径流量的唯一主导因素；农作区的径流系数显著高于荒草区（r〈0．05）。（2）农作区的入渗比率（入渗量／降雨量）低于荒草区；在持续降雨的情况下。农作区60cm以上土壤蓄水增量降低，但渗漏量保持不变．因此使入渗比率降低，而荒草区则在60cm以上土壤蓄水增量降低时，通过提高土壤的渗漏量保持较高的入渗比率。（3）降雨对土壤水分分布的影响受土壤初始含水量和垫面的影响。土壤初始含水量越低，降雨使土壤水分含量增量越大。在同等降雨置下，农作区只有40cm以上的土壤水分含量增加，而荒草区则为90cm以上。

Study on Rainfall Infiltration, Runoff and Soil Water Redistribution on Sloping Lands of Red Soil

Rainfall infiltration,runoff and soil water redistribution were studied in farming and grass slope lands of red soil in standard runoff observation field.The results showed that:(1) Runoff ratio in farming and grass slope lands were decreased with year;Rainfall was the most important factor to affect runoff;The runoff ratio of farming land was higher than that of grass land significantly(P<0.05).(2)The infiltration ratio of farming land was lower than that of grass land;The increase of water conservation amount in soil above 60 cm had a limit in farming and grass lands.The leakage of grass land would increase to keep the higher infiltration ratio under continuous rainfall,however the infiltration ratio would decrease due to no change in its leakage and lower water conservation increasing.(3)The effect of rainfall on soil water redistribution was affected by soil initial water content and slope land utilization pattern.Rainfall made soil increase more water if the initial soil water content lower.Water content in soil above 40 cm would increase due to rainfall in farming land,while rainfall would make water content increase in soil above 90 cm in grass land