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Effects of Pinus tabulaeformis litter cover on the sediment transport capacity of overland flow
Soil and Tillage Research ( IF 6.1 ) Pub Date : 2020-07-20 , DOI: 10.1016/j.still.2020.104685
Lin Ding , Suhua Fu , Baoyuan Liu , Bofu Yu , Guanghui Zhang , Hui Zhao

Sediment transport capacity (Tc) plays a pivotal role in process-based soil erosion models. Surface cover is an important factor that affects Tc; investigation into the potential effect of litter cover on Tc is limited. The objectives of this study were to quantify the effects of Pinus tabulaeformis litter cover on Tc; to explore various relationships between hydraulic variables, litter cover, and Tc; and to compare the similarities and differences of the effect of litter and stem cover on Tc. Experiments were conducted in a 5×0.38 m flume. The unit flow discharge varied from 1.316 × 10−3 to 3.947 × 10−3 m2 s−1, and the slope gradient varied from 8.8 to 26.8 %. Pine needles of Pinus tabulaeformis were selected to simulate litter cover. Seven levels of litter cover were considered: 0%, 5%, 10 %, 20 %, 30 %, 50 %, and 70 %. The median diameter of the test sediment was 0.35 mm. The results showed that Tc decreased exponentially as litter cover increased. Measured Tc could be predicted adequately (R2 = 0.96) by unit flow discharge, slope gradient and litter cover, or the stream power and litter cover. Flow velocity or unit stream power could predict the Tc equally well (R2 = 0.95) without including the cover term because the effect of litter cover on the Tc manifests itself in the increased resistance and reduced flow velocity. Tc is most sensitive to the slope gradient when the level of cover is low. The effect of litter cover on Tc could be greater than the unit flow discharge and slope gradient in relative terms when the level of cover exceeded 38 % and 81 %, respectively. The effect of stem cover on Tc is greater than that of litter cover, other variables being the same.



中文翻译:

的影响油松对坡面流的挟沙能力垃圾盖

在基于过程的土壤侵蚀模型中,泥沙输送能力(Tc)起着关键作用。表面覆盖是影响Tc的重要因素; 关于猫砂覆盖物对Tc的潜在影响的研究非常有限。本研究的目的是量化油松凋落物覆盖对Tc的影响; 探索水力变量,垫料覆盖率和Tc之间的各种关系;并比较凋落物和茎秆覆盖对Tc的影响的异同。实验是在5×0.38 m的水槽中进行的。单位流量排放量从1.316×10 -3到3.947×10 -3 m2 s -1,并且斜率梯度从8.8%变化到26.8%。选择油松的松针来模拟垫料覆盖。垃圾覆盖率分为七个级别:0%,5%,10%,20%,30%,50%和70%。测试沉积物的中值直径为0.35毫米。结果表明,随着凋落物覆盖率的增加,Tc呈指数下降。可以通过单位流量排放,坡度梯度和垃圾覆盖物或水流功率和垃圾覆盖物来适当地预测测得的TcR 2 = 0.96)。流速或单位流功率可以很好地预测TcR 2= 0.95),不包括覆盖项,因为垃圾覆盖对Tc的影响表现为阻力增加和流速降低。当覆盖水平较低时,Tc对斜率梯度最敏感。相对而言,当覆盖物水平分别超过38%和81%时,垃圾覆盖物对Tc的影响可能大于单位流量排放和坡度梯度。在其他变量相同的情况下,茎秆覆盖对Tc的影响大于垫料覆盖。

更新日期:2020-07-20
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