Estimation of the detachment rate in eroding rills in flume experiments using an REE tracing method
Estimation of the detachment rate in eroding rills in flume experiments using an REE tracing method
复制标题
使用 REE 示踪方法估算水槽实验中侵蚀细沟的脱离率
DOI：
10.1016/j.geoderma.2008.07.002
复制
发表时间：
2008-09
期刊：
影响因子：
6.1
通讯作者：
Jun Zhao
中科院分区：
文献类型：
--
作者：
Qingwen Zhang;Tingwu Lei;Jun Zhao
细沟侵蚀是耕作坡地上的一个严重问题。了解侵蚀细沟的剥离过程的机理，对于发展和完善基于过程的侵蚀预报模型具有重要意义。剥蚀率是单位时间内单位面积上剥蚀的泥沙量，是大多数物理侵蚀预报模型中的一个重要参数。目前对细沟侵蚀速率的研究大多使用空间平均的土壤侵蚀数据，由于缺乏空间分布的、同期的细沟侵蚀数据，这些数据提供的土壤侵蚀动力学信息很少。本研究的目的是使用稀土元素（REE）示踪方法估计侵蚀细沟的净剥离率。用十种稀土氧化物进行了水槽实验Ho 2 O3、Tb 4 O 7、Eu 2 O3、Yb 2 O3、Dy 2 O3、Sm 2 O3、La 2 O3、Tm 2 O3、CeO 2、Nd 2 O3等10种示踪剂与土壤混合后，在5个坡面不同地段进行了不同时间点的对比试验（8.74%、17.62%、26.78%、36.38%和46.6%）暴露于三种水流速（2、4和8 L min−1）。调节水流被引入水槽的上端，8米长，0.1米宽，分为10个相等的部分，每个部分含有不同的稀土-土壤混合物。从每个细沟段的净剥离率计算侵蚀和搬运材料的稀土元素浓度。从不同的片段沿着小溪，在不同的坡度和流速的剥离率进行了比较，直接从以前的研究估计，并发现增加坡度和流速。细沟净剥离率随含沙量的增加呈线性下降，随细沟长度的增加呈指数下降。REE的剥离数据及其与含沙量的关系与WEPP模型中使用的剥离函数一致，有助于理解细沟侵蚀过程。利用稀土元素追踪连续细沟中的剥蚀率是估算细沟剥蚀率空间分布的一种有效而有利的技术。
Rill erosion can be a serious problem on cultivated slopes. Understanding the mechanisms of the detachment process in eroding rills is important in developing and improving process-based erosion prediction models. The detachment rate, defined as the sediment amount detached from a unit area in a unit time, is a crucial parameter in most physical erosion prediction models. Most current studies on rill detachment rates use spatially averaged soil erosion data, which provides little information about soil erosion dynamics due to the lack of spatially distributed, contemporaneous rill erosion data. The objective of this study was to estimate the net detachment rate in eroding rills using a rare earth element (REE) tracing method. Flume experiments were conducted with ten REE oxides (Ho2O3, Tb4O7, Eu2O3, Yb2O3, Dy2O3, Sm2O3, La2O3, Tm2O3, CeO2, and Nd2O3) as tracers mixed with soil in different sections of five slopes (8.74%, 17.62%, 26.78%, 36.38%, and 46.6%) exposed to three water flow rates (2, 4, and 8 L min−1). Regulated water flow was introduced to the upper end of flumes, 8 m long and 0.1 m wide, which were divided into 10 equal segments, each containing a different REE–soil mixture. The net detachment rate from each rill segment was calculated from the REE concentrations in the eroded and transported material. The detachment rates from different segments along the rills, at different slope gradients and flow rates, were compared with those estimated directly from previous studies, and were found to increase with increasing slope gradient and flow rate. Results also showed that the net rill detachment rates decreased linearly with an increase in sediment concentration, and decreased exponentially with an increase in rill length. The REE-derived detachment data and their relationship with sediment concentrations are consistent with the detachment function used in the WEPP model, and are helpful in understanding the processes of rill erosion. Using REEs to trace detachment rates in continuous rills is a valid and advantageous technique for estimating the spatial distribution of the rill detachment rates.
登录
查看更多内容
影响因子：
6.5
作者：
Pu-ling Liu;Jun Tian;Peihua Zhou;Mingyi Yang;Hui Shi
通讯作者：
Pu-ling Liu;Jun Tian;Peihua Zhou;Mingyi Yang;Hui Shi
影响因子：
1.5
作者：
M. Nearing;G. R. Foster;L. Lane;S. Finkner
通讯作者：
M. Nearing;G. R. Foster;L. Lane;S. Finkner
影响因子：
2.9
作者：
Giménez, R;Govers, G
通讯作者：
Govers, G
影响因子：
2.9
作者：
X. Zhang;M. Nearing;V. Polyakov;J. Friedrich
通讯作者：
X. Zhang;M. Nearing;V. Polyakov;J. Friedrich
DOI：
10.1002/9783527612895
发表时间：
1997-02
期刊：
--
影响因子：
--
作者：
K. Lieser
通讯作者：
K. Lieser