论文部分内容阅读
喀斯特二元结构发育,地表水大量漏失,养分表现出快速流失的特点,然而养分流失的途径和机制尚不清楚.本研究从喀斯特关键带三维空间的视角,通过监测喀斯特灌丛坡地雨季典型降雨产流和氮素流失特征,基于氢氧稳定同位素技术对主要水文路径“新旧水”比例进行划分,并探讨氮素流失的主要途径和机制.结果表明:深层渗漏和壤中流是喀斯特灌丛坡地主要水文路径,两者分别占降雨量的71%和9%,地表径流仅占2%;深层渗漏、壤中流均以“旧水”为主,“旧水”比例分别为85%、61%;硝态氮浓度在深层渗漏中最高(1.97 mg·L~(-1)),铵态氮浓度在壤中流中最高(1.18 mg·L~(-1)),深层渗漏对氮素流失的贡献率达89.4%,显著高于地表径流和壤中流;“旧水”比例与硝态氮、铵态氮浓度和流失总量均表现出显著正相关关系,“旧水”可能是喀斯特坡地土壤-表层岩溶带系统携带氮素迁移的主要介质.以上研究能够为西南喀斯特地区坡地水资源合理配置和养分流失阻控技术研发提供理论支撑.
The development of karst dual structure, the large loss of surface water and the rapid loss of nutrients, however, the ways and mechanism of nutrient loss are not clear.In this study, from the perspective of three-dimensional space of karst key zone, Runoff and nitrogen loss, the main hydrological pathway “old and new water” was divided based on the stable oxygen and oxygen isotope techniques, and the main ways and mechanism of nitrogen loss were discussed.The results showed that the deep seepage and the soil middle flow were the karst The main hydrological path of the slope on the shrubbery are 71% and 9% of the rainfall and 2% of the surface runoff respectively. The deep seepage and the soil inflow are dominated by “old water” and “old water” (1.97 mg · L -1), the highest concentration of ammonium nitrogen (1.18 mg · L -1) in soil middle stream, ). The contribution rate of deep seepage to nitrogen loss was 89.4%, which was significantly higher than that of surface runoff and middle soil flow. The ratio of “old water” and nitrate nitrogen, ammonium nitrogen concentration and total loss showed significant positive Correlation, “old water ” may be the main slope of karst soil - surface karst system carrying nitrogen migration Quality above can study the rational allocation and nutrient loss resistance control technology research and development to provide theoretical support for the southwest slope of water resources in karst region.