华北山前平原农田关键带观测研究平台（栾城关键带观测平台）

Functions and Applications of Critical Zone Observatory of Luancheng Agro-Ecosystem Experimental Station, Chinese Academy of Sciences (Luancheng Critical Zone Observatory)

        沈彦俊(中国科学院遗传与发育生物学研究所农业资源研究中心 石家庄 050021;中国科学院栾城农业生态系统试验站 石家庄 050021)
        闵雷雷(中国科学院遗传与发育生物学研究所农业资源研究中心 石家庄 050021;中国科学院栾城农业生态系统试验站 石家庄 050021)
        吴林(中国科学院遗传与发育生物学研究所农业资源研究中心 石家庄 050021;中国科学院栾城农业生态系统试验站 石家庄 050021;中国科学院大学 现代农业科学学院 北京 100049)
        沈彦军(中国科学院遗传与发育生物学研究所农业资源研究中心 石家庄 050021;中国科学院栾城农业生态系统试验站 石家庄 050021)
        李红军(中国科学院遗传与发育生物学研究所农业资源研究中心 石家庄 050021;中国科学院栾城农业生态系统试验站 石家庄 050021)
        张广录(中国科学院遗传与发育生物学研究所农业资源研究中心 石家庄 050021;中国科学院栾城农业生态系统试验站 石家庄 050021)

         观测竖井;农田关键带;水-氮迁移过程;地下水量质管理

        observation caisson;agricultural critical zone;water-nitrogen transport;groundwater quantity and quality management (GQQM)

        中国科学院栾城农业生态系统试验站（以下简称“栾城站”）位于华北太行山前冲洪积平原的中段，是地下水灌区高产农业生态类型的典型代表。由于近几十年来大规模、高强度的农业生产，区域地下水超采严重，地下水污染风险加剧。然而，人类活动影响下的地表生态系统与地下含水层被厚包气带隔开，地表农业生产活动对地下水水量和水质的影响机理尚不明确。目前，开展贯穿整个包气带的原位监测试验，是揭示这一过程机理的唯一途径。因此，建立大型农田关键带观测平台，是开展农业与地下水关系研究的重要需求。在中国科学院野外站网络重点科技基础设施建设项目的支持下，栾城站建设的“栾城关键带观测平台”，通过对作物根系层—深层包气带—饱和带的土壤水、热、溶质等关键要素和变量的监测，可开展水分、溶质和污染物在厚包气带内的运移、转化规律研究，揭示饱和—非饱和过渡带水文过程及其与地下水补给关系，阐明农田生产活动的水肥迁移、转化及其对地下水量质变化的影响机制，为回答地表过程对地下水量质演化影响机理提供实验平台支持。

        The Luancheng Agro-Ecosystem Experimental Station, the Chinese Academy of Sciences, is located in the piedmont plain area of North China Plain and the middle section of the Taihang Mountain alluvial plain. It is a typical representative of the high-yield agricultural eco-system in the groundwater irrigation area. Due to the large-scale and high-intensity agricultural production in recent decades, the regional groundwater has been seriously over exploited, and the risk of groundwater pollution has increased. However, the surface agro-ecosystem and aquifer are separated by thick vadose zones, hence the mechanism of the impact of surface agricultural activities on the quantity and quality of groundwater is still unclear. The in-situ monitoring throughout the entire vadose zone is the only method to reveal the mechanism of this process. Therefore, the establishment of a large-scale critical zone observatory is the most important requisite for conducting research on the relationship between agriculture and groundwater. With the support of the cornerstone research infrastructure project for the field station network of the Chinese Academy of Sciences, Luancheng Station began to construct the “Water and Solute Cycle Observation Platform in Groundwater-Soil-Crop System” in 2016, and the construction was completed in November 2020. An observatory caisson with a depth of 48 m and an inner diameter of 2.8 m has been built. The platform was officially named ‘Luancheng Critical Zone Observatory' (LC-CZO). LC-CZO can measure the key variables such as soil water content, matric potential, soil temperature, and solute concentration in the root zone-deep vadose zone-saturated zone. The monitoring results enable the study on the patterns of the transport and transformation of water, solutes and pollutants in the thick vadose zone reveal the hydrological process of the saturated-unsaturated transition zone and its relationship with groundwater replenishment, explain the migration and transformation of nitrogen applied in farmland and its impact on groundwater quality, and provide experimental platform support for exploring the impact mechanism of land surface process on the groundwater quantity and quality.