Crop residue is an important factor affecting soil wind erosion. Few studies have tested the effects of crop residue on threshold friction velocities (U*t) which not only controls the initiation of wind erosion events but also the frequency and intensity of erosion events and thus the rate of land degradation. This study measured the threshold friction velocity (U*t) and aerodynamic roughness length (Z ₀) in the presence of winter wheat (Triticum aestivum L.), canola (Brassica napus L.), and garbanzo (Cicer arietinum) standing residue arrays to identify the sheltering capability against wind erosion of these different vegetation patterns. The influence of crop residue density and lateral cover (total roughness frontal area to soil surface area) on U*t and Z ₀ was tested in a wind‐tunnel. The results indicated U*t increased linearly with residue density for the three residue types and a similar trend was found for Z ₀. However, U*t and Z ₀ varied among crop residue types at the same residue density or frontal area index (λ). Based on the slope of regression analysis, U*t and Z ₀ of garbanzo were 40 and 25% higher than winter wheat and 43 and 119% higher than canola. This study suggested that crop residue type is important in determining U*t and Z ₀ when modeling wind erosion.

中文翻译：

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美国内陆西北太平洋内作物残留对阈值摩擦速度的影响

作物残渣是影响土壤风蚀的重要因素。很少有研究测试农作物残渣对阈值摩擦速度（U * t）的影响，该速度不仅控制风蚀事件的发生，而且还控制风蚀事件的频率和强度，从而控制土地退化的速度。本研究测量了存在冬小麦（Triticum aestivum L.），低芥酸菜子（Brassica napus L.）和鹰嘴豆（Cicer arietinum）时的阈值摩擦速度（U * t）和空气动力学粗糙度长度（Z ₀） ）站立的残留物阵列，以识别这些不同植被模式对风蚀的防护能力。在风洞中测试了农作物残渣密度和侧向覆盖度（总粗度锋面面积对土壤表面积）对U * t和Z _0的影响。结果表明，三种残渣类型的U * t随残渣密度线性增加，Z _0的趋势相似。但是，U * t和Z ₀在相同残渣密度或额叶面积指数（λ）的作物残渣类型之间变化。基于回归分析的斜率，U * t和Z ₀ 鹰嘴豆分别比冬小麦高40％和25％，比低芥酸菜籽高43和119％。这项研究表明，在模拟风蚀时，农作物残渣类型对于确定U * t和Z ₀非常重要。