Numerical analysis of soil water dynamics under leaf vegetable cultivated in a sandy soil with an artificial capillary barrier
Numerical analysis of soil water dynamics under leaf vegetable cultivated in a sandy soil with an artificial capillary barrier
复制标题
人工毛细管屏障沙土中叶类蔬菜土壤水分动态的数值分析
DOI：
10.1111/sum.12423
复制
发表时间：
2018
影响因子：
3.8
通讯作者：
and J. Simunek
中科院分区：
文献类型：
--
作者：
5.Wongkaew;A.;H. Saito;H. Fujimaki;and J. Simunek
采用由两层砾石和粗砂组成的人工毛细管屏障（CB）来提高沙质土壤根区的土壤保水能力，用于种植日本菠菜（Brassica rapavar.perviridis）。 CB 在特定条件下的性能可以使用数值模拟进行评估。然而，分析作物生长过程中CB系统土壤水动态的数值研究相对较少。本研究的目的是 (i) 评估 CB 在以不同流量灌溉的日本菠菜栽培过程中的性能，以及 (ii) 研究灌溉计划对根部吸水的影响。确定CB材料的土壤水力特性后，使用HYDRUS-1D进行数值分析。在大多数情况下，当描述土壤水力特性的双孔隙度模型用于砾石和粗砂时，HYDRUS-1D 结果与实验土壤含水量数据吻合得很好，无需任何校准。我们发现，双孔隙度模型能够减弱单孔隙度模型预测的不饱和导水率不切实际的急剧下降。数值模拟还表明，CB 在维持根区植物可用水同时最大化水分利用效率方面发挥着重要作用。数值模拟表明，设置CB层后，生育前期灌溉次数可减少一半，水分利用效率显着提高。
An artificial capillary barrier (CB), which consists of two layers of gravel and coarse sand, was used to improve the soil water retention capacity of the root zone of sandy soil for the cultivation of Japanese spinach (Brassica rapavar.perviridis). The performance of a CB under specific conditions can be evaluated using numerical simulations. However, there have been relatively few numerical studies analyzing soil water dynamics in CB systems during crop growth. The objectives of this study were (i) to evaluate the performance of a CB during the cultivation of Japanese spinach irrigated at different rates and (ii) to investigate the effect of the irrigation schedule on root water uptake. Numerical analysis was performed using HYDRUS‐1D after the soil hydraulic properties of the CB materials were determined. In most cases, the HYDRUS‐1D results agreed well with the experimental soil water content data without any calibration when the dual‐porosity model describing soil hydraulic properties was used for gravel and coarse sand. We found that the dual‐porosity model was able to attenuate the unrealistically steep reduction in the unsaturated hydraulic conductivity predicted by the single‐porosity model. The numerical simulations also showed that the CB played an important role in maintaining plant‐available water in the root zone while maximizing the water use efficiency. The numerical simulations revealed that the irrigation frequency could be reduced by half during the early growth stage, and the water use efficiency could be greatly improved with the CB layer installed.