重庆四面山林下典型植被对水分截留的影响

为探究西南地区林下植被与水分运移的定量关系,研究林下植被对水分截留的影响,在重庆四面山选取草珊瑚(Sarcandra glabra Nakai)、杜茎山(Maesa japonica Moritzi)、常山(Orixa japonica Thunb)3种典型常见灌木,采用人工模拟降雨方法分别研究了单株灌木、枯落物截留特征以及灌木和枯落物组合结构的截留特征。结果表明:(1)单株灌木、枯落物、灌木和枯落物组合结构对降雨的截留过程大致分为3个阶段,即快速截留阶段、饱和稳定阶段和降雨结束滞后冠滴雨阶段;(2)3种典型灌木草珊瑚、杜茎山、常山的截留量均随降雨强度的增大呈先增大后减小的规律;(3)枯落物最大截留量与降雨强度呈正相关关系,枯落物单位面积质量与枯落物平均最大、最小截留量间呈正相关关系;(4)与单株灌木和枯落物各自截留状况相比,灌木和枯落物组合结构最大截留量与降雨强度呈正相关关系,且快速截留阶段历时较长、最大截留量也较大。在雨强为35mm/h时,草珊瑚、杜茎山和其枯落物组合结构最大截留量大于灌木和枯落物各自最大截留量之和,常山和其枯落物组合结构最大截留量小于常山和其枯落物各自的最大截留量之和,在雨强为70,95mm/h时各组合结构最大截留量小于单株灌木和枯落物单独的最大截留量之和。林下灌木和枯落物在水分运移过程中均扮演了重要角色,其中枯落物对水分截留的贡献更大。因此,合理进行林下植被构建与配置能有效截留水分,对减少林地土壤侵蚀有一定的积极作用。

Effects of Undergrowth Typical Vegetation on Water Interception in the Simian Mountain of Chongqing

In order to explore the quantitative relationship between different undergrowth vegetation and moisture migration in Southwest China, and the impact of different undergrowth vegetation on water retention, three common shrubs, Sarcandra glabra Nakai, Maesa japonica Moritzi and Orixa japonica Thunb, were selected in the Simian Mountain. And the artificial rainfall method was used to study the interception characteristics of single shrubs and litters under different rainfall intensities, and the interception characteristics of compound structure. The results showed that:(1) The interception of single shrubs, the interception of litter and the interception of shrubs and litter assemblages were all divided into three stages, its were rapid trapping phase, saturated and stable phase, and a post-rainfall drainage phase. (2) The maximum and minimum interception rates of the studied three typical shrubs increased first and then decreased with the increase of rainfall intensity. (3) There was a positive correlation between the maximum interception of litter and rainfall intensity. The unit area quality of the litter with the mean maximum and minimum interception of the litter also showed a positive correlation. (4) Compared with single shrubs and litter alone test, the maximum interception of composite structure showed a positive correlation with rainfall intensity, and gave the longer rapid trapping phase and the larger maximum interception. When the rainfall intensity was 35 mm/h, the maximum interception of the composite structure of Sarcandra glabra Nakai and Maesa japonica Moritzi were larger than the sum of maximum interception of single experiment, but the maximum interception of the composite structure of Orixa japonica Thunb was less than the sum of maximum interception of single experiment. And the maximum interception of all the composite structure were less than the sum of the maximum interception of individual shrubs and litters when the rainfall intensity was 70 and 95 mm/h. Undergrowth shrubs and litters all played an important role in the process of water transport. Litters had a greater contribution to water interception. Therefore, rationally constructing and arranging the undergrowth vegetation could effectively retain water, which had a certain positive effect on reducing soil erosion in forest land.