Empirical models for predicting the erosion-reducing effects of plant roots during concentrated flow erosion
Empirical models for predicting the erosion-reducing effects of plant roots during concentrated flow erosion
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DOI：
10.1016/j.geomorph.2010.02.011
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发表时间：
2010-06-01
期刊：
影响因子：
3.9
通讯作者：
Poesen, J.
中科院分区：
文献类型：
--
作者：
De Baets, S.;Poesen, J.
最近的研究表明，植物根系可以显着降低土壤侵蚀率在集中流。早期的研究揭示了植物根系在受控实验室条件下的减蚀作用，并提出了一些仅适用于试验土壤和水流条件的方程。虽然试图解开不同的环境，植物和流动特性的影响，在集中径流的植物根系减少侵蚀的潜力，显着的影响是很难证明，因为数据的数量很少。因此，本研究的目的是汇集不同的数据集（共384个数据收集在标准化的实验条件下）一起构建基于几何模型预测（1）裸露和根渗透表土的土壤剥离率和（2）在集中流侵蚀过程中植物根系的侵蚀减少潜力。该模型，最好的预测绝对土壤剥离率从裸露和根渗透粉土或桑迪壤土表土（ASD）需要根密度，表土含水量之前，集中流侵蚀，容重和平均底流剪切应力的信息。虽然所有这些变量对ASD的预测都有很大的贡献，但验证结果表明数据仍然存在很大的分散性。特别是对于小的脱离率，该模型往往高估了观察值。另一个模型预测减少根渗透表土的剥离率相比，裸露的（RSD）也没有显示出良好的验证结果。然而，须根系统的模型被认为是非常有前途的。该模型仅使用根系密度和土壤质地信息解释了79%的变异，验证结果表明，该模型解释了验证数据集中69%的变异。然而，对于主根系统渗透的表土，模型结果并不令人满意。只有10%的变异，在验证数据集可以解释的模型，使用根密度和平均根直径作为输入变量。我们的结论是，渗透与须根的表土的侵蚀减少效果可以很好地预测，而相对侵蚀率为龙头根渗透表土仍然很难预测与研究的变量。需要更多的过程为基础的知识，以区分侵蚀减少的影响，从侵蚀加速的影响，主根渗透表土。(C)2010 Elsevier B.V.保留所有权利。
Recent research indicates that plant roots can reduce soil erosion rates during concentrated flow significantly. Earlier studies revealed the erosion-reducing effects of plant roots under controlled laboratory conditions and presented some equations applicable to the tested soil and flow conditions only. Although an attempt was made to unravel the impact of different environmental, plant and flow properties on the erosion-reducing potential of plant roots during concentrated runoff, significant effects were hard to demonstrate because of the small number of data. Therefore, the objective of this study is to pool different datasets (384 data collected under standardized experimental conditions in total) together for constructing empirically-based models predicting (1) soil detachment rates for both bare and root-permeated topsoils and (2) the erosion-reducing potential of plant roots during concentrated flow erosion. The model that best predicts absolute soil detachment rates from bare and root-permeated silt or sandy loam topsoils (ASD) requires information on root density, topsoil moisture content prior to concentrated flow erosion, bulk density and mean bottom flow shear stress. Although all these variables contribute significantly to the prediction of ASD, the validation results indicate that there is still a large scatter on the data. Especially for small detachment rates, the model tends to overestimate the observed values. Another model predicting the reduction in detachment rates of root-permeated topsoils compared to bare ones (RSD) does not show good validation results either. However, the model for fibrous root systems was found to be very promising. This model explains 79% of the variation using only root density and soil texture information and the validation results show that 69% of the variation in the validation dataset is accounted for by the model. For topsoils permeated with tap root systems, however, the model results were not satisfactory. Only 10% of the variation in the validation dataset could be explained by a model using root density and mean root diameter as input variables. We conclude that the erosion-reducing effect of topsoils permeated with fibrous roots can be predicted very well, whereas relative erosion rates for tap root-permeated topsoils still remain difficult to predict with the studied variables only. More process-based knowledge is needed to distinguish erosion-reducing effects from erosion-accelerating effects for tap root-permeated topsoils. (C) 2010 Elsevier B.V. All rights reserved.