三种水土保持措施下红壤坡地径流产沙特性

为了给红壤区选取、布设水土保持措施提供有效依据,基于连续两年试验区降雨资料,分析不同水土保持措施与对照处理径流小区的减流减沙效益,研究降雨与径流产沙的相关性。结果表明:有效侵蚀性降雨发生在春夏两季的比例较大,4—5月降雨量占全年降雨总量比例达38.7%~43.2%;相对于对照小区,植被措施及工程措施的年均减流率均大于90%,减沙率大于99%,耕作措施减流率及减沙率分别为79.6%和93.4%;按照侵蚀强度分级标准,对照小区两年均为剧烈侵蚀,植被措施、工程措施小区为微度侵蚀,而耕作措施分别达到极强度侵蚀和轻度侵蚀,从减流减沙效果而言,植被措施及工程措施较耕作措施的效果更显著;相关性分析结果表明,不同处理下的径流量与降雨量相关性最密切,对照小区与植被措施小区的侵蚀量与径流量呈极显著的相关性。

Study on runoff and sediment yield characteristics of red-soil slope land under three water-soil conservation measures

In order to lay an effective basis for selecting and laying out water-soil conservation measures in red-soil area, the runoff and sediment reduction benefits from different water-soil conservation measures and the runoff plots treated for comparison are analyzed in accordance with the rainfall data of the experimental plots for two consecutive years, and then the correlation between rainfall and the runoff and sediment yield is studied as well. The result shows that the proportion of the occurrence of the effective erosive rainfall in spring and summer is larger, while the proportions of the precipitations in April and May reach 38. 7% 43. 2% of the total annual precipitation. Compared with the check plot, the annual average runoff reduction ratio is larger than90% and the sediment reduction ratio is larger than 99% for both the plots with vegetation measure and engineering measures, while the runoff reduction ratio and the sediment reduction ratio are 79. 6% and 93. 4% respectively for the plot with tillage measure. According to the erosion intensity classification standard, the erosion intensity of the check plot for two years belongs to severe erosion and the erosion intensities of both the plots with vegetation measure and engineering measure are the slight erosions, while plot with tillage measure reaches the most intensified erosion and slight erosion respectively. From the aspect of the effect of runoff and sediment reduction, the effects of the vegetation measure and engineering measure are more significant than that of the tillage measure. The correlative analysis result shows that the runoff is most closely correlated with the precipitation under the conditions of different treatments and a significant correlation is there between the erosion and runoff of both the check plot and the plot with vegetation measure.