Consolidation effects on relationships among soil erosion properties and soil physical quality indicators
Consolidation effects on relationships among soil erosion properties and soil physical quality indicators
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DOI：
10.1016/j.still.2019.104550
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发表时间：
2020-04
影响因子：
6.5
通讯作者：
G. Wilson;Tianyu Zhang;R. Wells;Baoyuan Liu
中科院分区：
文献类型：
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作者：
G. Wilson;Tianyu Zhang;R. Wells;Baoyuan Liu
耕作后土壤的干湿循环会迅速改变土壤的物理性质，但对这些变化如何影响土壤侵蚀却知之甚少。根据土壤容重、饱和导水率、含水量、土壤渗透强度和表面抗剪强度随干湿循环的变化，建立了预测土壤可蚀性（Kd）和固结临界剪应力（τc）的方程。将来自四个对比土壤系列的风干土壤松散地填充到20个土壤圆柱体（总共80个）中以模拟新耕作条件。土壤物理和侵蚀特性，确定在6个时间段（0，1，3，5，7，10天）后，每天模拟降雨量为33毫米h-1的1小时和24小时的排水/干燥。喷射试验装置用于测定Kd和τc。由于模拟降水事件后的固结，堆积密度随时间增加，其中最大增加（总量的50- 100%）发生在第一次润湿/干燥循环后。Onstad固结模型倾向于过度预测这一初始表面容重的增加，而指数模型更好地代表了四种土壤测试的表面和深度平均容重的变化。剪切强度和土壤渗透阻力显着增加后的第一个湿/干循环，然后下降到一个相当稳定的值，在随后的湿/干循环。饱和导水率Ks随累积降雨量的增加而迅速下降，指数衰减模型不能与Ksas土壤固结的下降相匹配。累积降雨量、土壤容重、饱和导水率和1.3cm土层渗透阻力是土壤可蚀性对固结的最佳响应指标。临界剪切力的最佳指标是累积降雨量、1.3cm处土壤渗透阻力和饱和导水率。由于这些侵蚀参数的截距取决于土壤系列，因此预测耕作后土壤侵蚀随时间的变化将具有土壤特异性。
Consolidation of soil by wetting and drying cycles following tillage rapidly changes the soil physical properties but little is known about how these changes impact soil erosion. The objective of this study was to develop equations to predict soil erodibility (Kd) and critical shear stress (τc) in response to consolidation based upon changes in soil bulk density, saturated hydraulic conductivity, water content, soil penetration strength and surface shear strength following a series of wetting and drying cycles. Air-dried soil from four contrasting soil series was loosely filled into 20 soil cylinders (80 total) to simulate freshly tilled conditions. Soil physical and erosion properties were determined at six time periods (0, 1, 3, 5, 7, 10 days) following daily simulated rainfall of 33 mm h−1for 1 h and 24 h of drainage/drying. The Jet Test device was used to determine Kd, and τc.The bulk density increased with time due to consolidation following the simulated precipitation events with the largest increase (50–100 % of the total) occurring after the first wetting/drying cycle. The Onstad consolidation model tended to over-predict this initial surface bulk density increase, whereas, an exponential model better represented the surface and depth-averaged bulk density changes for the four soils tested. The shear strength and soil penetration resistance increased dramatically after the first wetting/drying cycle then decreased to a fairly stable value in response to subsequent wetting/drying cycles. The saturated hydraulic conductivity, Ks, decreased so rapidly with accumulated rainfall that an exponential decay model could not match the decrease in Ksas the soil consolidated. The best indicators of erodibility response to consolidation were accumulated rain, surface bulk density, saturated hydraulic conductivity and soil penetration resistance at the 1.3 cm depth. The best indicators of critical shear stress were accumulated rainfall, soil penetration resistance at 1.3 cm and saturated hydraulic conductivity. Because these erosion parameters had intercepts that were dependent upon the soil series, prediction of changes in soil erosion with time following tillage will be soil-specific.