Parameter Estimation of a Root Water Uptake Model under Salinity Stress
Parameter Estimation of a Root Water Uptake Model under Salinity Stress
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DOI：
10.2136/vzj2007.0025
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发表时间：
2008-02
影响因子：
2.8
通讯作者：
H. Fujimaki;Y. Ando;Yibin Cui;M. Inoue
中科院分区：
文献类型：
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作者：
H. Fujimaki;Y. Ando;Yibin Cui;M. Inoue
盐碱胁迫下根系水分吸收的准确预测有助于干旱半干旱地区有效的水分管理。我们提出了一种成本有效且可靠的方法来确定广泛使用的宏观根系吸水模型中的参数值。以大豆[Glycine max (L.]稳定。在温室里。使用了六根柱子，每根柱子上有一株植物：三根在盐度胁迫下，其他的提供潜在的蒸腾作用。在三根色谱柱中分别插入三个时域反射探针来观察水的含量和电导率。在白天，土壤表面被覆盖以防止蒸发。人工测量柱的重量以获得每日蒸腾。应力期结束后，拆柱得到根密度分布。两个参数值是通过最小化观测值与计算值之间的平方差和而反向确定的。通过将线性插值的渗透势代入应力响应函数，计算了各深度和时间的吸水量。优化后的日蒸腾量与观测值吻合较好。此外，在中低应力下，优化后的三个响应函数偏差较小，表明了方法的可靠性。
Accurate prediction of root water uptake under salinity stress contributes to efficient water management in arid and semiarid lands. We present a cost‐effective and reliable method to determine parameter values in a widely used macroscopic root water uptake model. We conducted column experiments using soybean [Glycine max (L.) Merr.] in a greenhouse. Six columns with one plant each were used: three were under salinity stress, the others provided potential transpiration. Three time‐domain reflectometry probes were inserted into each of the three columns to observe water content and electrical conductivity. In the daytime, the soil surface was covered to prevent evaporation. Weight of the columns was manually measured to obtain daily transpiration. After the stress period, root density distributions were obtained by dismantling the columns. Two parameter values were inversely determined by minimizing the sum of square difference between observed and calculated daily transpiration rates. Water uptake at each depth and time was calculated by substituting linearly interpolated osmotic potential into a stress response function. Optimized daily transpiration agreed well with the observations. In Addition, deviation in the three optimized response functions was small at low‐to‐moderate stress, indicating the reliability of the method.