基于降水-地表水-地下水相互作用的岩溶石漠化地区土壤地表流失-地下漏失机理及防治方法研究

Rocky desertification is a severe problem that threatens the ecological environment of karst areas in China, restricting regional economic and social development meanwhile. Soil erosion in the desertification area is not only manifested as surface loss, but also the underground leakage. The essence of the reason leading to surface-underground soil erosion is the dual structure of the karst system and rainfall is the main external factor. Besides, the circulation and interaction of Precipitation, surface water and groundwater is the key issue of researching the direction and the trend of surface-underground soil erosion. This application will complete four parts. First, it is proposed to carry out the typical small watershed scale hydrogeological survey in Guizhou Plateau National Rock Desertification Control Demonstration Zone and the Sustainable Development Experimental Zone, using hydrogeochemical analysis, tracer test, field test, SWAT numerical simulation, to analyze the interaction of precipitation, surface water and groundwater comprehensively in different grade of rocky desertification area. Second, the indoor scale test of water-soil (rock) interaction in epi-karst zones and karst pipelines is carried out to analyze the mechanism of surface-underground soil erosion. Third, in view of the difference of rock desertification mechanism in limestone and dolomite area, the difference of surface-underground soil erosion in different lithological areas was analyzed. Finally, the local methods of prevention and control soil erosion are explored according to the different rocky desertification level.

石漠化是威胁我国岩溶地区生态环境安全、制约区域经济社会发展的重大瓶颈和突出问题。石漠化地区的土壤流失不仅表现为地表流失，而且存在着地下漏失现象。岩溶系统的二元结构是导致地表-地下土壤流失的实质，降雨是土壤流失的主要外营力，降水-地表水-地下水“三水”循环过程和相互作用是土壤地表流失-地下漏失方向和趋势的关键性问题。本项申请拟结合贵州高原国家石漠化治理示范区和可持续发展实验区，开展典型小流域尺度水文地质调查，利用水文地球化学分析、示踪试验、野外试验、SWAT数值模拟，综合分析不同等级石漠化地区降水-地表水-地下水相互作用；在此基础上，开展表层岩溶裂隙带和岩溶管道中水-土（岩）相互作用的室内模拟试验，据以分析土壤地表流失和地下漏失的机理；特别针对石灰岩和白云岩地区石漠化的差异性，分析不同岩性地区土壤地表流失和地下漏失的差异；根据不同岩性和石漠化等级，形成因地制宜的土壤流失防治方法。

围绕国家石漠化工程治理长期演进急需解决的关键科学技术问题，以贵州岩溶高原中强度石漠化地区贞丰关岭-花江、轻度石漠化地区毕节撒拉溪、潜在石漠化地区施秉、无石漠化地区荔波为研究区域，通过野外调查和监测、室内模拟实验、数值模拟和数据分析等手段，凝练出岩溶地区土壤地表流失/地下漏失的关键性指标为降雨、坡度、裂隙、基岩裸露率、植被覆盖率，揭示了石漠化地区大气降水-地表水-地下水“三水”转化机理及其驱动下的水土地表流失/地下漏失规律，定量计算了重点区域贞丰关岭-花江的三水转化量和水土流失量，比较了石灰岩和白云岩地区水土流失和石漠化演化的差异性。研发了适用于岩溶地区坡面尺度的野外水土流失监测技术和室内表层岩溶裂隙带土壤地表流失/地下漏失模拟技术，提高了岩溶地区水土流失监测精准度；建立了适用于典型岩溶高原流域尺度的分布式水文模型和水土流失预测方法，并提出水土流失防治的重点区域规划和因地制宜的防治措施与建议。研究成果为项目合作单位在贵州石漠化地区进行火龙果与适生牧草优化配置技术“果-草模式”、花椒矮化密植与水肥一体化技术示范提供重要的技术支撑。.目前相关成果已发表或录用标注论文11篇，已受理发明专利1项，依托本项目培养中国科协青年托举工程人才1名和硕博士研究生7名，组织和参与了13次国内外地质环境相关的学术大会和学术交流。项目均按计划实施，已经完成研究目标。