Knowledge of the water fluxes within the soil-vegetation-atmosphere system is crucial to improve water use efficiency in irrigated land. Many studies have tried to quantify these fluxes, but they encountered difficulties in quantifying the relative contribution of evaporation and transpiration. In this study, we compared three different methods to estimate evaporation fluxes during simulated summer conditions in a grass-covered lysimeter in the laboratory. Only two of these methods can be used to partition total evaporation into transpiration, soil evaporation and interception. A water balance calculation (whereby rainfall, soil moisture and percolation were measured) was used for comparison as a benchmark. A HYDRUS-1D model and isotope measurements were used for the partitioning of total evaporation. The isotope mass balance method partitions total evaporation of 3.4 mm d?1 into 0.4 mm d?1 for soil evaporation, 0.3 mm d?1 for interception and 2.6 mm d?1 for transpiration, while the HYDRUS-1D partitions total evaporation of 3.7 mm d?1 into 1 mm d?1 for soil evaporation, 0.3 mm d?1 for interception and 2.3 mm d?1 for transpiration. From the comparison, we concluded that the isotope mass balance is better for low temporal resolution analysis than the HYDRUS-1D. On the other hand, HYDRUS-1D is better for high temporal resolution analysis than the isotope mass balance.
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机译:对土植被环境中的水量助水系统的知识至关重要,以提高灌溉土地的用水效率。许多研究试图量化这些势态,但它们遇到困难量化蒸发和蒸腾的相对贡献。在这项研究中,我们比较了三种不同的方法来估算实验室草地覆盖的液晶计中的模拟夏季条件期间蒸发通量。这些方法中只有两种方法可用于将总蒸发分配成蒸腾,土壤蒸发和拦截。使用水平衡计算(测量降雨,土壤水分和渗滤量)作为基准比较。氢气-1D模型和同位素测量用于分配总蒸发。同位素质量平衡方法将3.4mm d 2的总蒸发分配到0.4mm d 2中的蒸发,用于土壤蒸发,0.3mm d 2截取,2.6mm d 2蒸腾,而蒸腾液体蒸发总蒸发3.7 mm d?1进入1mm d 2,用于土壤蒸发,0.3mm d 2为截取,2.3mm d 2为蒸腾。从比较中,我们得出结论,同位素质量平衡比氢气-1D更低的时间分辨率分析更好。另一方面,Hydrus-1d比同位素质量平衡更好地高度的时间分辨率分析。
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