Implementing small scale processes at the soil-plant interface - the role of root architectures for calculating root water uptake profiles
Implementing small scale processes at the soil-plant interface - the role of root architectures for calculating root water uptake profiles
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DOI：
10.5194/hess-14-279-2010
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发表时间：
2010-01-01
影响因子：
6.3
通讯作者：
Hildebrandt, A.
中科院分区：
文献类型：
--
作者：
Schneider, C. L.;Attinger, S.;Hildebrandt, A.
在本文中，我们提出了一个独立的根系水分吸收模型aRoot，该模型计算了考虑根系网络内部和周围水流的任何散装土壤水流模型的汇项。模型的边界条件为大气需水量和土壤体积含水量。决定植物吸水调节的变量是土壤-根界面的土壤水势。在当前版本中，我们提出了一个与3d Richards模型耦合的aRoot实现。应用耦合模型研究了根系构型对根系吸水性空间分布的影响。为此，我们对同一物种（一个月龄高粱）根系的整体（50个实现）根系的吸收进行了建模。调查分为两种情况，一种是根径向阻力较高(A)，一种是根径向阻力较低(B)。我们将两个aRoot情景的结果与使用传统Feddes模型计算的根系吸水量进行了比较。所生成根系的垂直密度分布相似。与此相反，不同个体之间的垂直吸水曲线差异很大，在情景B中比在情景a中差异更大。此外，不同模型个体在不同的土壤体积湿度下出现吸水限制，特别是在情景a中。此外，aRoot模型模拟显示，随着时间的推移，吸水从根密度较高的土层向根密度较低的土层重新分布。这种行为与观测结果一致，但federes模型没有重现。
In this paper, we present a stand alone root water uptake model called aRoot, which calculates the sink term for any bulk soil water flow model taking into account water flow within and around a root network. The boundary conditions for the model are the atmospheric water demand and the bulk soil water content. The variable determining the plant regulation for water uptake is the soil water potential at the soil-root interface. In the current version, we present an implementation of aRoot coupled to a 3-D Richards model. The coupled model is applied to investigate the role of root architecture on the spatial distribution of root water uptake. For this, we modeled root water uptake for an ensemble (50 realizations) of root systems generated for the same species (one month old Sorghum). The investigation was divided into two Scenarios for aRoot, one with comparatively high (A) and one with low (B) root radial resistance. We compared the results of both aRoot Scenarios with root water uptake calculated using the traditional Feddes model. The vertical rooting density profiles of the generated root systems were similar. In contrast the vertical water uptake profiles differed considerably between individuals, and more so for Scenario B than A. Also, limitation of water uptake occurred at different bulk soil moisture for different modeled individuals, in particular for Scenario A. Moreover, the aRoot model simulations show a redistribution of water uptake from more densely to less densely rooted layers with time. This behavior is in agreement with observation, but was not reproduced by the Feddes model.