摘要
冲沟侵蚀是一种剧烈的土壤侵蚀过程,导致冲沟发育区地表形态处于显著变化的非稳定状态。通过封禁使植被自然恢复是元谋干热河谷冲沟治理的主要模式之一,但在沟道植被持续恢复与冲沟显著发育的综合作用下,沟道土壤碳氮含量的变化趋势仍有待明晰。选择元谋干热河谷1条典型冲沟,在沟内随机布设81个1 m×1 m的样方,分别在2012年和2017年的旱季初期,监测81个样方的植被指数、侵蚀/沉积过程引起的地表高程变化,以及冲沟土壤理化性质。结果表明:(1)2017年沟道内植被状况明显好于2012年,且沟床表面径流冲刷范围内的植被变化最为明显,其盖度、株数、株高分别增加313.61%,94.29%,33.33%。(2)5年间冲沟发育区以沉积为主,侵蚀样方和沉积样方的比例分别为22.22%和77.78%。随着植被盖度的增加,土壤砂粒含量呈下降趋势,粉粒含量呈增加趋势。(3)封禁期间虽然植被恢复显著,但土壤碳氮并没有明显改善。土壤碳氮不仅与植被盖度和粉粒百分比呈显著正相关,还与样方点高程变化呈显著负相关。冲沟内地形起伏的剧烈程度显著高于坡面侵蚀,并对冲沟表层土壤碳氮产生显著影响。研究有助于查明植被恢复及冲沟发育对土壤碳氮的综合影响,并为干热河谷冲沟退化生态系统的修复提供理论支持。
Gully erosion is a kind of intense soil erosion process,which leads to the surface morphology of gully development area in an unstable state of significant change.Natural restoration of vegetation through prohibition is one of the main modes of gully management in Yuanmou Dry-hot valley.However,under the comprehensive effect of continuous restoration of gully vegetation and significant development of gully,the changing trend of soil carbon and nitrogen content in gully remains to be clearly defined.In this study,a typical gully in Yuanmou Dry-hot valley was selected,and 81 samples of 1 m×1 m were randomly arranged.The vegetation index,elevation changes caused by the erosion/sedimentation process,and soil physical and chemical properties of the 81 samples were measured at the beginning of the dry season in 2012 and 2017,the results showed that:(1)The vegetation conditions in the gully in 2017 were significantly better than that in 2012,and the vegetation changes within the range of runoff erosion on the surface of the gully bed were the most obvious,and the vegetation cover,number,and height increased by 313.61%,94.29%,and 33.33%,respectively.(2)During the five years,the gully development area was dominated by sedimentation,and the proportions of erosion and sedimentation were 22.22% and 77.78%,respectively.With the increase of vegetation cover,the sand content of the soil showed a decreasing trend,and the silt content showed an increasing trend.(3)Although the vegetation recovered significantly during the period of prohibition,the soil carbon and nitrogen did not improve significantly.Soil carbon and nitrogen were not only significantly positively correlated with vegetation cover and soil particle-size,but also significantly negatively correlated with elevation changes of quadrate points.The severity of topographical changes in the gully was significantly higher than that of surface erosion,and it had a significant impact on the carbon and nitrogen of the surface soil of the gully.This study will help to identify the comprehensive effects of vegetation restoration and gully development on soil carbon and nitrogen,and provide support for the restoration of the degraded gully ecosystem in Dry-hot valley.
作者
文孝丽
董一帆
杨己
段兴武
WEN Xiaoli;DONG Yifan;YANG Ji;DUAN Xingwu(Institute of International Rivers and Eco-Security,Yunnan University,Kunming 650091)
出处
《水土保持学报》
CSCD
北大核心
2021年第4期282-288,共7页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(U2002209,41671288)
第二次青藏高原综合科学考察研究项目(2019QZKK0307)。
关键词
植被恢复
冲沟侵蚀
土壤碳氮
高程变化
干热河谷
vegetation restoration
gully erosion
soil carbon and nitrogen
elevation change
Dry-hot valley