Sensitivity of simulated hillslope subsurface flow to rainfall patterns, soil texture and land use
Sensitivity of simulated hillslope subsurface flow to rainfall patterns, soil texture and land use
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模拟山坡地下流对降雨模式、土壤质地和土地利用的敏感性
DOI：
10.1111/sum.12282
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发表时间：
2016
影响因子：
3.8
通讯作者：
Zhu Q.
中科院分区：
文献类型：
--
作者：
Liao K-H.;Lv L-G.;Yang G-S.;Zhu Q.
了解山坡地下流的产生对于控制农业非点养分损失非常重要。本研究使用基于物理的山坡水文模型 HYDRUS-2D 来评估模拟地下流对降水、土壤质地和土地利用之间相互作用的敏感性。利用茶园山坡上两个监测点2013年1月1日至2014年8月23日的土壤湿度数据来校准该模型的van Genuchten-Mualem水力参数。针对六种不同的质地类别（壤土、壤土、淤泥、粉砂壤土、粘壤土和粘土）和四种土地利用类型（茶园、森林、草地和裸土），对不同的降水强度（6.0、15.0、30.0、45.0、60.0 和 76.0 毫米/天）和频率（时间间隔为 1、5、 10、15、20 和 25 天）。结果表明，山坡径流以地下流为主，受降水和前期湿度条件的影响。观察到地下流启动的平均山坡土壤湿度阈值为 0.18 m3/m3。高降水强度（即 75.0 毫米/天）大大增加了所有土壤质地的地下流量。此外，裸土山坡对降雨模式的敏感性比植被（即草地、茶园和森林）山坡高两倍以上。这些发现表明，极端降水事件和土地利用变化将增加山坡地下流的风险。因此，应提出优化施肥策略和土地利用规划来控制山坡面源养分流失。
Knowledge of the generation of subsurface flow for hillslopes is important for controlling agricultural nonpoint nutrient losses. This study used a physically based hillslope hydrologic model HYDRUS‐2D to assess the sensitivity of simulated subsurface flow to the interactions between precipitation, soil texture and land use. Soil moisture data from 1 January 2013 to 23 August 2014 at two monitoring sites on a tea plantation hillslope were used to calibrate the van Genuchten–Mualem hydraulic parameters for this model. For six different textural classes (loamy sand, loam, silt, silt loam, clay loam and clay) and four land‐use types (tea garden, forest, grassland and bare soil), scenario‐based simulations were carried out for varied precipitation intensities (6.0, 15.0, 30.0, 45.0, 60.0 and 76.0 mm/day) and frequencies (time intervals of 1, 5, 10, 15, 20 and 25 days). Results indicated that the hillslope run‐off was dominated by subsurface flow, which was influenced by precipitation and antecedent moisture conditions. A threshold value of 0.18 m3/m3of mean hillslope soil moisture was observed for the initiation of subsurface flow. High precipitation intensity (i.e. 75.0 mm/day) substantially increased subsurface flow for all soil textures. In addition, the sensitivity of the bare soil hillslope to rainfall patterns was more than two times higher than that of the vegetated (i.e. grassland, tea garden and forest) hillslope. These findings suggest that extreme precipitation events and land‐use change will increase the risks of subsurface flow on hillslopes. Therefore, optimal fertilizer application strategy and land‐use planning should be proposed for controlling the hillslope nonpoint nutrient losses.