摘要
以2013年陕北富县"7·21"特大暴雨滑坡侵蚀灾害为对象,通过调查暴雨侵蚀区典型小流域植被条件及滑坡特征,测定滑坡壁不同土层的根系重量、土壤孔隙度、土壤容重等指标,研究子午岭林区暴雨滑坡侵蚀与植被根系的关系。根据不同类型植被根系深度和滑坡侵蚀特征(侵蚀深度、滑动面宽度及长度,滑坡体体积、滑动距离等),可将林区暴雨滑坡侵蚀划分为三类:以草本植被为主的A类滑坡,以灌丛植被为主的B类滑坡,以乔本植被为主的C类滑坡。结果表明,三类滑坡侵蚀的侵蚀深度与其对应植被类型的根系深度相近,且植被及其根系会加剧滑坡侵蚀的发生。在此次暴雨滑坡侵蚀中,滑坡侵蚀强度受植物根系重量、土壤孔隙度、土壤容重等因素的共同影响,但根系重量对滑坡侵蚀强度的影响占主导作用,通过建立二者之间的关系式发现,根系对滑坡侵蚀的贡献率超过80%。不同植被类型的滑坡侵蚀深度不同,且滑坡侵蚀强度也存在差异,表明植被根系不仅具有塑造滑坡侵蚀特征的作用,而且会影响滑坡侵蚀的强弱程度。在强降水基础上,特别是当降水量达到诱发滑坡灾害发生的临界值时,植被及其根系会加剧滑坡侵蚀的发生。在今后工作中,要因地制宜合理配置各类植被,同时结合其它措施,以便提高植被防治水土流失的作用,更好地发挥植被的水土保持效益。
To clarify the relationship between surface landslide and vegetation, a case study of the ＂7 ~ 21 ＂ rainstorm disaster in Fuxian County, northern Shaanxi Province, was conducted. A typical small watershed in the Ziwuling forest area was selected as the research site. The study investigated the vegetation conditions and landslide characteristics and simultaneously collected soil samples （ root weight, soil bulk density, and saturated water content） from different soil layers of the landslide cliff. According to different vegetation conditions （i.e., vegetation type, dominant species, root depth） and shallow landslide characteristics （i. e., erosion depth, width and length of sliding surface, landslide volume, sliding distance） , 37 surface landslides were grouped into three types （A, B, and C）. The dominant vegetation of types A, B, and C were mainly herbage, shrub, and arbor, respectively. The scale of the landslides was in the order of type A 〈 B 〈 C.The average erosion depth was 45, 63, and 96 cm, and the landslide volume was about 100-500, 300-700, and 500- 1500 m3, respectively, for types A, B, and C. Some landslide materials accumulated at the bottom of the slope of types B and C slides, and some landslide materials were even deposited at the gully bed of type C. The results showed that the different types of surface landslide presented unique landslide erosion depths and that these depths were normally equal to the root depth. Moreover, landslide erosion intensity increased with vegetation root weight. Surface landslide was aggravated by vegetation and its roots. We also found that shallow landslide intensity was affected mainly by three factors, root weight, soil porosity, and soil bulk density, and that the heavy rainstorm was the triggering factor in this surface landslide erosion. However, soil porosity and soil bulk density were both affected by root weight, and a linear regression analysis indicated that only root weight made a positive contribution to landslide erosion intensi
出处
《生态学报》
CAS
CSCD
北大核心
2016年第15期4635-4643,共9页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(41271299)
