藏东南施工便道植被恢复对坡面水土流失的影响  

Influence of Vegetation Restoration in Construction Access Roads on Soil and Water Loss in Southeastern Xizang Autonomous Region

作　　者：冉心昊 王冠 李亚桐 肖辉杰[1] Ran Xinhao;Wang Guan;Li Yatong;Xiao Huijie(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学水土保持学院,北京100083

出　　处：《水土保持通报》2024年第4期20-32,共13页Bulletin of Soil and Water Conservation

基　　金：国家重点研发计划项目“西南高山峡谷区水土流失综合防治技术与示范”(2022YFF1302901);国铁集团科研项目“铁路建设项目水土流失智能监测技术及应用效果研究”(J2022Z001)。

摘　　要：[目的]明晰施工便道上、下边坡在植被恢复条件下的坡面产流产沙过程,揭示施工便道建设扰动后植被恢复对藏东南生态脆弱的亚高山森林灌丛区坡面尺度水土流失的影响,为施工便道工程扰动后水土流失防治和植被恢复提供理论依据。[方法]选取施工便道上、下边坡扰动后不同植被恢复条件下的典型坡面,进行室内模拟降雨试验,研究工程扰动后上、下边坡4种植被覆盖度(0%,30%,60%,90%),3种坡度(15°,30°,45°),2种雨强(30,60 mm/h)条件下的坡面产流产沙过程,明确施工便道植被恢复对水土流失的影响。[结果](1)施工便道工程扰动后,在上、下边坡裸土坡面进行植被恢复能有效延缓初始产流时间,随着植被覆盖度增加,延缓初始产流时间的效果增强,且植被的延缓产流效应在上边坡更为明显。(2)在0%~60%植被覆盖度范围内,上、下边坡稳定产流速率随植被覆盖度的增加而显著降低,60%与90%植被覆盖度的稳定产流速率接近。相比裸土坡面,60%,90%植被覆盖度的减流效益分别为59%~75%,58%~77%,表明减流作用的植被临界覆盖度为60%。(3)植被覆盖度为30%,60%时,减沙效益分别达到29%~82%,86%~96%。植被覆盖度在60%以下,当覆盖度增加,减沙作用显著增强,超过此临界覆盖度,即使增加覆盖度,其减沙效益也变化不大。(4)在相同植被覆盖度、坡度和雨强条件下,挖方形成的上边坡总产流量总是高于填方形成的下边坡,而下边坡总产沙量始终高于上边坡,反映出施工便道扰动后,挖方、填方边坡在坡面土壤侵蚀方面的显著差异。[结论]在藏东南施工便道扰动区的水土流失防治中,60%植被恢复率兼具较好的防治效益和经济可行性,且在水土保持措施布设时,挖方边坡更需要“控水”而填方边坡应偏重“阻沙”,只有充分考虑其差异才能在施工便道扰动区达到更好的水土保持效果。[Objective] We aimed to elucidate the process of runoff and sediment production on the upper and lower slopes of construction access roads under vegetation recovery conditions,reveal the impact of vegetation recovery on soil and water loss at the slope scale after the disturbance caused by the construction of access roads in an ecologically fragile subalpine forest and shrubland area of Southeastern Xizang Autonomous Region,in order to provide a theoretical basis for the prevention and control of soil and water loss and vegetation restoration after the disturbance caused by the construction road project.[Methods] Typical slopes under different vegetation recovery conditions after disturbances on the upper and lower slopes of construction access roads were selected for indoor simulated rainfall experiments.In this study,we investigated the processes of runoff and sediment production under four types of vegetation coverage(0%,30%,60%,and 90%),three slopes(15°,30°,and 45°),and two rainfall intensities(30,60 mm/h) after engineering disturbance to determine the impact of vegetation recovery in construction access roads on soil and water loss.[Results](1) After the engineering disturbance of the construction access roads,vegetation recovery on the bare upper and lower slopes effectively delayed the initial runoff time,and this effect became more pronounced with increasing vegetation coverage,especially on the upper slopes.(2) When the vegetation coverage was within the range of 0 to 60%,the stable runoff rate on both the upper and lower slopes significantly decreased with increasing vegetation coverage,wherein the stable runoff rates under 60% and 90% vegetation coverage were similar.Compared with bare slopes,the benefits of runoff reduction under 60% and 90% vegetation coverage were 59%—75% and 58%—77% respectively,indicating that the critical vegetation coverage value for runoff reduction was 60%.(3) Sediment reduction benefits under 30% and 60% vegetation coverage reached 29%—82% and 86%—96% respectively.

关 键 词：产流产沙过程 植被覆盖度 减流减沙效益 亚高山森林灌丛 施工便道 

分 类 号：S157.1[农业科学—土壤学]