赣北第四纪红壤坡地降雨侵蚀力的计算与分析

Analysis of rainfall erosivity on sloping land of Quaternary Red Earth in North Jiangxi Province

降雨侵蚀力是建立土壤侵蚀预报模型的基础。为探讨赣北第四纪红壤坡地降雨侵蚀力的最佳组合形式、时间变异特征及其简易估算方法,通过赣北典型的第四纪红壤坡地区2001—2005年的实测资料,对各种降雨参数的单因子、复合因子与土壤流失量进行统计分析,对降雨侵蚀力的时间变异特征进行初步探讨,并对降雨侵蚀力和降雨量进行相关分析。结果表明:∑EI30可作为试验区降雨侵蚀力的最佳组合形式;降雨侵蚀力年际分布不均匀,年内分配主要集中在4—9月(占91.66%),总体上降雨侵蚀力与降雨量的年际和月际变化基本一致;次降雨的降雨侵蚀力与降雨量之间的相关系数为0.838,达到极显著水平。据此可建立基于降雨量的降雨侵蚀力简易模型,对无降雨过程资料地区的降雨侵蚀力计算具有参考价值。

Rainfall erosivity is necessary to develop the soil erosion model. To study the law of rainfall erosivity on sloping land of quaternary red earth, an experimental spot was estabished on the representative area to investigate rainfall and sediment from 2001 to 2005. The relations between rainfall parameters and sediment amount were analyzed. Then, rainfall erosivity was calculated and its distribution regular in time was studied. At last, the relation between rainfall erosivity and precipitation was analyzed for easy caculation. It is suggested that ∑ EI30 can represent commendably rainfall erosivity in the study area. Rainfall erosivity is variabile in yearly and monthly distribution, and mainly distributes between April and September, accounting for 91.66 percent among that in one year. It is also shown that rainfall erosivity has similar trendency in time distribution with precipitation, and their correlation coefficient is 0. 838. The prediction equation of rainfall erosivity is important to estimate rainfall erosivity when the continuous record of rainfall is lack.