矿区植被蒸散量估算及虚拟水量化

    Estimation of vegetation evapotranspiration and quantification of virtual water in mining areas

    • 摘要: 矿区复垦地的生态修复过程中,植被蒸散作用对水资源消耗具有重要影响。虚拟水理论为水资源管理提供了新视角,但目前针对矿区生态植被的虚拟水量化研究较少。本研究旨在估算矿区复垦地不同植被类型的蒸散量,并基于虚拟水理论量化其虚拟水含量及水足迹,分析矿区水资源的优化配置策略。本研究基于大柳塔煤矿区微生物复垦示范基地,选取沙棘、紫穗槐和樟子松为研究对象,采用热红外成像技术结合能量平衡方程计算植被蒸散量,并利用CROPWAT模型估算其需水量。同时,以沙棘为例,引入虚拟水理论进行水足迹计算,分析不同植被类型的灌溉需水量、虚拟水含量和水资源利用效率。研究结果表明,接菌处理显著增加了植被蒸散量,2014年樟子松接菌区的蒸散量最高,日蒸散量达到8.17 mm/d,而2012年樟子松对照区的日蒸散量最低,为4.94 mm/d。参照蒸散速率在2012—2021年间变化范围为2.51~3.29 mm/d,随温度和风速增加而升高,随相对湿度增加而降低。不同植被类型的需水量差异显著,其中,沙棘最大(7 469.5 mm),紫穗槐最小(4 619.4 mm)。沙棘的虚拟水含量在2012—2021年间呈先升后降趋势,2020年达到峰值(17 657.60 m3/t),且蓝水足迹占比远高于绿水足迹。此外,矿区的水资源利用效率普遍较低,最大值仅为54.80%,表明节水措施亟待优化。本研究验证了CROPWAT模型在矿区生态植被水资源评估中的适用性,并首次量化了矿区植被的虚拟水含量和水足迹。研究结果可为矿区生态恢复中的水资源优化管理提供理论依据,建议通过提高绿水利用比例、优化灌溉制度及引入耐旱植被,提高水资源利用效率,促进矿区生态系统的可持续恢复。

       

      Abstract: In the ecological restoration of mining reclamation areas, vegetation evapotranspiration plays a crucial role in water resource consumption. The virtual water theory offers a new perspective for water resource management, yet limited research has been conducted on the quantification of virtual water in ecological vegetation within mining areas. This study aims to estimate the evapotranspiration of different vegetation types in a mining reclamation area and quantify their virtual water content and water footprint based on the virtual water theory, providing insights into the optimization of water resource allocation. The study is conducted in the microbial reclamation demonstration base of the mining area, selecting Hippophae rhamnoides, Amorpha fruticosa, and Pinus sylvestris var. mongolica as research subjects. Thermal infrared imaging technology combined with the energy balance equation is employed to calculate vegetation evapotranspiration, while the CROPWAT model is used to estimate vegetation water requirements. Additionally, Hippophae rhamnoides is used as a case study to quantify virtual water and water footprint, analyzing the irrigation water demand, virtual water content, and water use efficiency of different vegetation types. The findings indicate that inoculation treatment significantly increased vegetation evapotranspiration. The highest evapotranspiration is observed in the inoculation area of Pinus sylvestris, reaching 8.17 mm/d in 2014. while the lowest is in the Pinus sylvestris var. mongolica control area in 2012 (4.94 mm/d). The reference crop evapotranspiration in the mining area varied between 2.51-3.29 mm/d from 2012 to 2021, increasing with temperature and wind speed while decreasing with relative humidity. Significant differences in water demand among vegetation types are found, with Hippophae rhamnoides requiring the highest amount of water (7 469.5 mm) and Amorpha fruticosa the lowest (4 619.4 mm). The virtual water content of Hippophae rhamnoides exhibits a rising and then declining trend, peaking in 2020 at 17 657.60 m3/t, with blue water footprint significantly surpassing green water footprint. Moreover, the overall water use efficiency in the mining area is low, with a maximum efficiency of only 54.80%, highlighting the urgent need for improved water-saving strategies. This study validates the applicability of the CROPWAT model in assessing water resource consumption of ecological vegetation in mining areas and, for the first time, quantifies the virtual water content and water footprint of vegetation in a mining reclamation site. The findings provide theoretical support for optimizing water resource management in mining ecological restoration. It is recommended to enhance the utilization of green water, optimize irrigation strategies, and introduce drought-resistant vegetation to improve water use efficiency and promote sustainable ecological recovery in mining areas.

       

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