Liao Renkuan, Yang Peiling, Wu Wenyong, Ren Shumei
State Key Laboratory of Simulation and Regulation of Water Cycles in River Basins, China Institute of Water Resources and Hydropower Research, Beijing, China.
College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing, China.
PLoS One. 2016 Aug 9;11(8):e0159936. doi: 10.1371/journal.pone.0159936. eCollection 2016.
The widespread use of superabsorbent polymers (SAPs) in arid regions improves the efficiency of local land and water use. However, SAPs' repeated absorption and release of water has periodic and unstable effects on both soil's physical and chemical properties and on the growth of plant roots, which complicates modeling of water movement in SAP-treated soils. In this paper, we proposea model of soil water movement for SAP-treated soils. The residence time of SAP in the soil and the duration of the experiment were considered as the same parameter t. This simplifies previously proposed models in which the residence time of SAP in the soil and the experiment's duration were considered as two independent parameters. Numerical testing was carried out on the inverse method of estimating the source/sink term of root water uptake in the model of soil water movement under the effect of SAP. The test results show that time interval, hydraulic parameters, test error, and instrument precision had a significant influence on the stability of the inverse method, while time step, layering of soil, and boundary conditions had relatively smaller effects. A comprehensive analysis of the method's stability, calculation, and accuracy suggests that the proposed inverse method applies if the following conditions are satisfied: the time interval is between 5 d and 17 d; the time step is between 1000 and 10000; the test error is ≥ 0.9; the instrument precision is ≤ 0.03; and the rate of soil surface evaporation is ≤ 0.6 mm/d.
高吸水性聚合物（SAPs）在干旱地区的广泛应用提高了当地土地和水资源的利用效率。然而，SAPs反复吸水和释水对土壤物理化学性质以及植物根系生长具有周期性和不稳定的影响，这使得模拟经SAP处理土壤中的水分运动变得复杂。在本文中，我们提出了一种经SAP处理土壤的土壤水分运动模型。将SAP在土壤中的停留时间和实验持续时间视为同一参数t。这简化了先前提出的模型，在那些模型中，SAP在土壤中的停留时间和实验持续时间被视为两个独立参数。对在SAP影响下土壤水分运动模型中根系吸水源/汇项估计的反演方法进行了数值测试。测试结果表明，时间间隔、水力参数、测试误差和仪器精度对反演方法的稳定性有显著影响，而时间步长、土壤分层和边界条件的影响相对较小。对该方法的稳定性、计算和准确性进行综合分析表明，若满足以下条件，则所提出的反演方法适用：时间间隔在5天至17天之间；时间步长在1000至10000之间；测试误差≥0.9；仪器精度≤0.03；土壤表面蒸发速率≤0.6毫米/天。
