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首页> 外文期刊>Hydrology and Earth System Sciences >Sensitivity of water stress in a two-layered sandy grassland soil tovariations in groundwater depth and soil hydraulic parameters
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Sensitivity of water stress in a two-layered sandy grassland soil tovariations in groundwater depth and soil hydraulic parameters

机译：两层沙质草地土壤水分胁迫对地下水深度和土壤水力参数变化的敏感性

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摘要

Monitoring and modelling tools may improve irrigation strategies in precisionagriculture. We used non-invasive soil moisture monitoring, a crop growthand a soil hydrological model to predict soil water content fluctuations andcrop yield in a heterogeneous sandy grassland soil under supplementaryirrigation. The sensitivity of the soil hydrological model to hydraulicparameters, water stress, crop yield and lower boundary conditions wasassessed after integrating models. Free drainage and incremental constanthead conditions were implemented in a lower boundary sensitivity analysis. Atime-dependent sensitivity analysis of the hydraulic parameters showed thatchanges in soil water content are mainly affected by the soil saturatedhydraulic conductivity Ks and the Mualem–van Genuchten retention curveshape parameters n and α. Results further showed that differentparameter optimization strategies (two-, three-, four- or six-parameteroptimizations) did not affect the calculated water stress and water contentas significantly as does the bottom boundary. In this case, a two-parameterscenario, where Ks was optimized for each layer under the condition of a constant groundwater depth at 135–140 cm, performed best. A larger yieldreduction, and a larger number and longer duration of stress conditionsoccurred in the free drainage condition as compared to constant boundaryconditions. Numerical results showed that optimal irrigation schedulingusing the aforementioned water stress calculations can save up to 12–22 %irrigation water as compared to the current irrigation regime. This resultedin a yield increase of 4.5–6.5 %, simulated by the crop growth model.
机译：监测和建模工具可以改善精密农业的灌溉策略。我们使用非侵入性土壤湿度监测，作物生长和土壤水文模型来预测补充灌溉条件下非均质砂质草地土壤中的水分波动和作物产量。整合模型后，评估了土壤水文模型对水力参数，水分胁迫，作物产量和下边界条件的敏感性。在较低的边界敏感性分析中实施了自由排水和增量恒压条件。水力参数随时间变化的敏感性分析表明，土壤含水量的变化主要受土壤饱和水力传导率 K s 和Mualem-van Genuchten保留曲线形状参数 n 和α。结果进一步表明，不同的参数优化策略（两个，三个，四个或六个参数优化）对水应力和含水量的影响不如底部边界显着。在这种情况下，在地下水深度恒定在135-140 cm的条件下，针对每层优化 K s 的两参数方案效果最佳。与恒定边界条件相比，在自由排水条件下会出现更大的减产，以及更大数量和更长的应力条件持续时间。数值结果表明，与当前的灌溉制度相比，使用上述水应力计算得出的最优灌溉调度可节省高达12-22％的灌溉水。通过作物生长模型模拟，这导致单产提高4.5-6.5％。

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