喀斯特槽谷区生态退化与修复专题导读

在国家重点研发计划项目——"喀斯特槽谷区土地石漠化过程及综合治理技术研发与示范(2016YFC0502300)"的支持下,经过项目组全体成员三年的共同努力,在喀斯特槽谷区生态退化与修复方面取得了一些重要进展。主要有:(1)2000—2015年槽谷区土壤侵蚀总量逐年减少,年平均侵蚀模数逐年降低,槽谷区植被覆盖明显提高;(2)拉巴豆地埂篱根土复合体不仅能有效提高喀斯特土壤的粒径大小和增强土体的抗剪/冲性能,并且能够利用大气N_2合成植物生长所需的氮肥,从而提高土壤肥力,可望实现石漠化治理中生态效应和经济效应的双赢;(3)喀斯特槽谷区隧道建设改变了地下水流场并降低了地下水位,进而降低了土壤微生物丰度和多样性,而增加了适应干旱的微生物种群,并导致土壤质量的降低;隧道建设加速了坡面产流和土壤流失,加剧了土地石漠化,从而导致生态退化;(4)随着槽谷区退化生态系统的恢复,生态系统的生态服务功能得到提升。

The Eco-degradation and restoration in Karst Trough Valley Area: An introduction

Supported by the national key research and development program of China, entitled "Research and development of comprehensive rehabilitation measures for land rocky desertification in karst trough valley area (2016YFC0502300)", some important progress has been made in ecological degradation and restoration in karst trough valley area after three years'' joint efforts of all members of the project team. The most important progress includes:(1) From 2000 to 2015, the total amount of soil erosion and the annual average erosion modulus decreased year by year, meanwhile the vegetation coverage increased significantly in the trough valley area; (2) Root and root-soil matrix of Dolichos lablab L. hedgerows can not only effectively improve the particle size of karst soil, soil anti-scourability and soil shear strength, but also Dolichos lablab L. can use the atmospheric N₂ to synthesize nitrogen fertilizer for plant growth and then improve soil fertility, which is expected to achieve a win-win situation of ecological and economic effects during the rocky desertification rehabilitation; (3) Tunnels excavation in karst trough valley area altered the natural hydrogeological flow system and lowered groundwater level, and consequently reduced the relative abundance and diversity of soil microbial species, but increased the microbial population adapted to drought, leading to the decrease of soil quality. Tunnel construction also accelerated slope runoff and soil erosion, leading to aggravate land rocky desertification, and consequently led to ecological degradation in karst trough valley area; (4) With the restoration of degraded karst ecosystem, the ecological service functions of karst ecosystem have been improved in karst trough valley area.