The Experts below are selected from a list of 3258 Experts worldwide ranked by ideXlab platform
Sha Wang - One of the best experts on this subject based on the ideXlab platform.
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flume experiment to verify wepp Rill Erosion equation performances using loess material
Journal of Soils and Sediments, 2016Co-Authors: Nan Shen, Zhanli Wang, Sha WangAbstract:Purpose This study aims to verify the performances of Water Erosion Prediction Project (WEPP) Rill Erosion equation using loess material by investigating the variations of soil detachment rate with sediment load by Rill flow, quantifying the response of soil detachment rate to sediment load, and comprehensively examining WEPP Rill Erosion equation, so as to provide scientific basis for the application of WEPP model on the loess plateau and to sufficiently understand the response of soil detachment rate to sediment load.
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flume experiment to verify wepp Rill Erosion equation performances using loess material
Journal of Soils and Sediments, 2016Co-Authors: Nan Shen, Zhanli Wang, Sha WangAbstract:This study aims to verify the performances of Water Erosion Prediction Project (WEPP) Rill Erosion equation using loess material by investigating the variations of soil detachment rate with sediment load by Rill flow, quantifying the response of soil detachment rate to sediment load, and comprehensively examining WEPP Rill Erosion equation, so as to provide scientific basis for the application of WEPP model on the loess plateau and to sufficiently understand the response of soil detachment rate to sediment load. The experiment was conducted in a Rill flume with a soil-feeding hopper and was specifically designed to isolate the effect of sediment load on detachment rate. Loess material was collected from a typical hilly region of the Loess Plateau, Ansai, Shaanxi, China. The test soil was quantitatively fed into Rill flow by a soil-feeding hopper to produce different sediment loads. Seven unit flow discharges (1.11, 1.56, 2.00, 2.44, 2.89, 3.33, and 3.78 × 10−3 m2 s−1) were combined with six slopes (10.51, 15.84, 21.26, 26.79, 32.49, and 38.39 %). The sediment transport capacity was measured for each combination. The detachment rate was measured for each combination under seven sediment loads, which were 0, 10, 25, 50, 75, 90, and 100 % of the sediment transport capacity. Soil detachment rate decreased with the increase of sediment load. Levels of sediment load in 0, 10, 25, 50, 75, 90, and 100 % reduced detachment rate in rates of 0, 18.93, 36.36, 56.28, 70.15, 83.42, and 92.19 %, respectively. The response relationship of detachment rate to sediment load by Rill flow was described well by a negative linear equation (R 2 range from 0.8489 to 0.9982, P < 0.01), and the vertical and horizontal intercepts of the linear equation represented the detachment and transport capacities, respectively (R 2 = 0.9955, NSE = 0.9788 for D c ; R 2 = 0.9957, NSE = 0.9635 for T c ), as expressed by the WEPP Rill Erosion equation. The WEPP Rill Erosion equation predicted the soil detachment rate very well (R 2 = 0.9667, NSE = 0.9611). Sediment load transported by Rill flow has a negative influence on soil detachment rate in Rills. Introducing sediment load as a factor in model equation of detachment is essential for developing an accepted Erosion model. The WEPP Rill Erosion equation could correctly reflect the response relationship of detachment rate to sediment load in this flume experiment and has a good applicability to loess material.
Fenli Zheng - One of the best experts on this subject based on the ideXlab platform.
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effects of sheet and Rill Erosion on soil aggregates and organic carbon losses for a mollisol hillslope under rainfall simulation
Journal of Soils and Sediments, 2019Co-Authors: Yiliang Jiang, Fenli Zheng, Leilei Wen, Haiou ShenAbstract:Characterizations of soil aggregates and soil organic carbon (SOC) losses affected by different water Erosion patterns at the hillslope scale are poorly understood. Therefore, the objective of this study was to quantify how sheet and Rill Erosion affect soil aggregates and soil organic carbon losses for a Mollisol hillslope in Northeast China under indoor simulated rainfall. The soil used in this study was a Mollisol (USDA Taxonomy), collected from a maize field (0–20 cm depth) in Northeast China. A soil pan with dimensions 8 m long, 1.5 m wide and 0.6 m deep was subjected to rainfall intensities of 50 and 100 mm h−1. The experimental treatments included sheet Erosion dominated (SED) and Rill Erosion dominated (RED) treatments. Runoff with sediment samples was collected during each experimental run, and then the samples were separated into six aggregate fractions (0–0.25, 0.25–0.5, 0.5–1, 1–2, 2–5, > 5 mm) to determine the soil aggregate and SOC losses. At rainfall intensities of 50 and 100 mm h−1, soil losses from the RED treatment were 1.4 and 3.5 times higher than those from the SED treatment, and SOC losses were 1.7 and 3.8 times greater than those from the SED treatment, respectively. However, the SOC enrichment ratio in sediment from the SED treatment was 1.15 on average and higher than that from the RED treatment. Furthermore, the loss of 0.25 mm aggregates occupied 53.2 to 67.3% of the total sediment aggregates for the RED treatment. For the organic carbon loss among the six aggregate fractions, the loss of 0–0.25 mm aggregate organic carbon dominated for both treatments. When rainfall intensity increased from 50 to 100 mm h−1, aggregate organic carbon loss increased from 1.04 to 5.87 times for six aggregate fractions under the SED treatment, whereas the loss increased from 3.82 to 27.84 times for six aggregate fractions under the RED treatment. This study highlights the effects of sheet and Rill Erosion on soil and carbon losses at the hillslope scale, and further study should quantify the effects of Erosion patterns on SOC loss at a larger scale to accurately estimate agricultural ecosystem carbon flux.
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understanding Erosion processes using rare earth element tracers in a preformed interRill Rill system
Science of The Total Environment, 2018Co-Authors: Xunchang J Zhang, Gang Liu, Fenli ZhengAbstract:Tracking sediment source and movement is essential to fully understanding soil Erosion processes. The objectives of this study were to identify dominant Erosion process and to characterize the effects of upslope interRill Erosion on downslope interRill and Rill Erosion in a preformed interRill-Rill system. A coarse textured soil with 2% clay and 20% silt was packed into a physical model of a scaled small watershed, which was divided into eight topographic units and was tagged with eight rare earth element (REE) oxides. Three 30-min rains were made at the sequential intensities of 60, 90, and 120mmh-1, and runoff and sediment were collected every 2min at the outlet. REE concentration in sediment was measured and used to estimate source contributions after fine-enrichment correction. Results showed that interRill Erosion rate and sediment concentration increased with downslope distance, indicating that sediment transport might have controlled interRill Erosion rates. In contrast, Rill Erosion rate was limited by Rill detachment and development process. Rill Erosion contributed most soil loss; however, the proportion decreased from 78 to 61% as rainfall intensity increased and Rill network matured over three rains. InterRill Erosion was more sensitive than Rill Erosion to rainfall intensity increases. The former was mostly affected by rainfall intensity in this experimental setup, while the latter was controlled by flow discharge, gradient, and Rill evolution stage. The greatest sediment concentration and delivery rate occurred in the stage of the fastest Rill development. The increased sediment delivery from interRill areas appeared to suppress Rill detachment by concentrated flow. This study enhanced our understanding of interRill and Rill Erosion processes and provided the scientific insights for improving soil Erosion models.
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Understanding Erosion processes using rare earth element tracers in a preformed interRill-Rill system
'Elsevier BV', 2018Co-Authors: Xun-chang Zhang, Fenli Zheng, Gang Liu, Liu, Author), Northwest A&f Univ, Inst Soil Water Conservat, 26 Xinong Rd, Yangling 712100, Shaanxi, China.Abstract:Tracking sediment source and movement is essential to fully understanding soil Erosion processes. The objectives of this study were to identify dominant Erosion process and to characterize the effects of upslope interRill Erosion on downslope interRill and Rill Erosion in a preformed interRill-Rill system. A coarse textured soil with 2% clay and 20% silt was packed into a physical model of a scaled small watershed, which was divided into eight topographic units and was tagged with eight rare earth element (REE) oxides. Three 30-min rains were made at the sequential intensities of 60, 90, and 120 ram h(-1), and runoff and sediment were collected every 2 min at the outlet. REE concentration in sediment was measured and used to estimate source contributions after fine-enrichment correction. Results showed that interRill Erosion rate and sediment concentration increased with downslope distance, indicating that sediment transport might have controlled interRill Erosion rates. In contrast, Rill Erosion rate was limited by Rill detachment and development process. Rill Erosion contributed most soil loss; however, the proportion decreased from 78 to 61% as rainfall intensity increased and Rill network matured over three rains. InterRill Erosion was more sensitive than Rill Erosion to rainfall intensity increases. The former was mostly affected by rainfall intensity in this experimental setup, while the latter was controlled by flow discharge, gradient, and Rill evolution stage. The greatest sediment concentration and delivery rate occurred in the stage of the fastest Rill development. The increased sediment delivery from interRill areas appeared to suppress Rill detachment by concentrated flow. This study enhanced our understanding of interRill and Rill Erosion processes and provided the scientific insights for improving soil Erosion models. (C) 2018 Elsevier B.V. All rights reserved
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A laboratory study on Rill network development and morphological characteristics on loessial hillslope
'Springer Science and Business Media LLC', 2018Co-Authors: Chao Qin, Fenli Zheng, Haiou Shen, Zheng, Fl Author), Northwest A&f Univ, Inst Soil Water Conservat, State Key Lab Soil Eros Dryland Fa China., Zheng, Fl Author), Chinese Acad Sci, Inst Soil Water Conservat, Yangling 712100, Shaanxi, Peoples & China., Zheng, Fl Author), Mwr, Yangling 712100, Shaanxi, Peoples R China.Abstract:Rills are basic pathways for runoff, sediment, and pollutant transport at hillslopes within agricultural watershed. The objectives of this study were to investigate the development processes of Rill network and morphological characteristics and to examine their affecting factors. A soil box (10 m long, 1.5 m wide, and 0.5 m deep) was subjected to four successive simulated rains under rainfall intensity of 90 mm h(-1) with slope gradients of 15A degrees and 25A degrees. Digital elevation models (5 mm resolution) were created from the terrestrial laser scanning measurements. Total soil loss was 46.3 and 61.0 kg m(-2) at the 15A degrees and 25A degrees slope gradients, and Rill Erosion occupied over 75% of the total soil loss. Soil loss and Rill Erosion were expressed as power equations to the product of slope gradient and accumulated rainfall. Rill networks evolved in a converging way and reached maturity in the fourth rain. Main Rill length and Rill width, depth, and degree of contour line departure increased with increased rains, while Rill width/depth ratio showed the opposite trend. Secondary Rill length and Rill density increased in the first two rains, and then both decreased in the latter two rains. Scour effect of lateral interfluve flow and meander cutoffs of Rill flow were two sub-processes of Rill piracy. Rill length and density decreased due to Rill piracy specific in merging of secondary Rills into main Rills. Plow pan and secondary headcuts played key roles in main Rill bed incision and sidewall expansion processes, while both had little impact on secondary Rills. Results of this study can improve the understanding of how plow pan, Rill piracy, and secondary headcut affect Rill network and morphologies and provide fundamental knowledge for designing Rill prevention practices
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developing equations to explore relationships between aggregate stability and erodibility in ultisols of subtropical china
Catena, 2017Co-Authors: Hai Xiao, Fenli Zheng, Jiaqiong Zhang, Feinan HuAbstract:Abstract A soil aggregate represents a key soil structural unit that influences several physical soil properties such as water infiltration, runoff and Erosion. The relationships between soil aggregate stability and interRill and Rill erodibility are critical to process-based Erosion prediction models yet remain unclear, likely due to the difficulty of distinguishing between interRill and Rill-eroded sediment during the Erosion process. This study was designed to partition interRill and Rill Erosion rates and relate them to the aggregate stability of Ultisols in subtropical China. Six kinds of rare earth elements (REEs) were applied as tracers mixed with two cultivated soils developed over Quaternary red clay or shale at six slope positions. Soil aggregate stability was determined by the Le Bissonnais (LB)-method. Simulated rainfall of three intensities (60, 90 and 120 mm h − 1 ) was applied to a soil plot (2.25 m long, 0.5 m wide, 0.2 m deep) at three slope gradients (10°, 20° and 30°) for a duration of 30 min after runoff initiation. The results indicated that Rill and interRill Erosion rates in the soil developed over shale were considerably greater than those in the soil developed over Quaternary red clay. Equations using an aggregate stability index A s to replace the erodibility factor of interRill and Rill Erosion in the Water Erosion Prediction Project (WEPP) model were constructed after analysing the relationships between estimated and measured Rill and interRill Erosion data. The results show that these equations based on A s have the potential to improve methods for assessing interRill and Rill Erosion erodibility synchronously for subtropical Ultisols by using an REE tracing method.
Zhanli Wang - One of the best experts on this subject based on the ideXlab platform.
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flume experiment to verify wepp Rill Erosion equation performances using loess material
Journal of Soils and Sediments, 2016Co-Authors: Nan Shen, Zhanli Wang, Sha WangAbstract:Purpose This study aims to verify the performances of Water Erosion Prediction Project (WEPP) Rill Erosion equation using loess material by investigating the variations of soil detachment rate with sediment load by Rill flow, quantifying the response of soil detachment rate to sediment load, and comprehensively examining WEPP Rill Erosion equation, so as to provide scientific basis for the application of WEPP model on the loess plateau and to sufficiently understand the response of soil detachment rate to sediment load.
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flume experiment to verify wepp Rill Erosion equation performances using loess material
Journal of Soils and Sediments, 2016Co-Authors: Nan Shen, Zhanli Wang, Sha WangAbstract:This study aims to verify the performances of Water Erosion Prediction Project (WEPP) Rill Erosion equation using loess material by investigating the variations of soil detachment rate with sediment load by Rill flow, quantifying the response of soil detachment rate to sediment load, and comprehensively examining WEPP Rill Erosion equation, so as to provide scientific basis for the application of WEPP model on the loess plateau and to sufficiently understand the response of soil detachment rate to sediment load. The experiment was conducted in a Rill flume with a soil-feeding hopper and was specifically designed to isolate the effect of sediment load on detachment rate. Loess material was collected from a typical hilly region of the Loess Plateau, Ansai, Shaanxi, China. The test soil was quantitatively fed into Rill flow by a soil-feeding hopper to produce different sediment loads. Seven unit flow discharges (1.11, 1.56, 2.00, 2.44, 2.89, 3.33, and 3.78 × 10−3 m2 s−1) were combined with six slopes (10.51, 15.84, 21.26, 26.79, 32.49, and 38.39 %). The sediment transport capacity was measured for each combination. The detachment rate was measured for each combination under seven sediment loads, which were 0, 10, 25, 50, 75, 90, and 100 % of the sediment transport capacity. Soil detachment rate decreased with the increase of sediment load. Levels of sediment load in 0, 10, 25, 50, 75, 90, and 100 % reduced detachment rate in rates of 0, 18.93, 36.36, 56.28, 70.15, 83.42, and 92.19 %, respectively. The response relationship of detachment rate to sediment load by Rill flow was described well by a negative linear equation (R 2 range from 0.8489 to 0.9982, P < 0.01), and the vertical and horizontal intercepts of the linear equation represented the detachment and transport capacities, respectively (R 2 = 0.9955, NSE = 0.9788 for D c ; R 2 = 0.9957, NSE = 0.9635 for T c ), as expressed by the WEPP Rill Erosion equation. The WEPP Rill Erosion equation predicted the soil detachment rate very well (R 2 = 0.9667, NSE = 0.9611). Sediment load transported by Rill flow has a negative influence on soil detachment rate in Rills. Introducing sediment load as a factor in model equation of detachment is essential for developing an accepted Erosion model. The WEPP Rill Erosion equation could correctly reflect the response relationship of detachment rate to sediment load in this flume experiment and has a good applicability to loess material.
Nan Shen - One of the best experts on this subject based on the ideXlab platform.
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flume experiment to verify wepp Rill Erosion equation performances using loess material
Journal of Soils and Sediments, 2016Co-Authors: Nan Shen, Zhanli Wang, Sha WangAbstract:Purpose This study aims to verify the performances of Water Erosion Prediction Project (WEPP) Rill Erosion equation using loess material by investigating the variations of soil detachment rate with sediment load by Rill flow, quantifying the response of soil detachment rate to sediment load, and comprehensively examining WEPP Rill Erosion equation, so as to provide scientific basis for the application of WEPP model on the loess plateau and to sufficiently understand the response of soil detachment rate to sediment load.
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flume experiment to verify wepp Rill Erosion equation performances using loess material
Journal of Soils and Sediments, 2016Co-Authors: Nan Shen, Zhanli Wang, Sha WangAbstract:This study aims to verify the performances of Water Erosion Prediction Project (WEPP) Rill Erosion equation using loess material by investigating the variations of soil detachment rate with sediment load by Rill flow, quantifying the response of soil detachment rate to sediment load, and comprehensively examining WEPP Rill Erosion equation, so as to provide scientific basis for the application of WEPP model on the loess plateau and to sufficiently understand the response of soil detachment rate to sediment load. The experiment was conducted in a Rill flume with a soil-feeding hopper and was specifically designed to isolate the effect of sediment load on detachment rate. Loess material was collected from a typical hilly region of the Loess Plateau, Ansai, Shaanxi, China. The test soil was quantitatively fed into Rill flow by a soil-feeding hopper to produce different sediment loads. Seven unit flow discharges (1.11, 1.56, 2.00, 2.44, 2.89, 3.33, and 3.78 × 10−3 m2 s−1) were combined with six slopes (10.51, 15.84, 21.26, 26.79, 32.49, and 38.39 %). The sediment transport capacity was measured for each combination. The detachment rate was measured for each combination under seven sediment loads, which were 0, 10, 25, 50, 75, 90, and 100 % of the sediment transport capacity. Soil detachment rate decreased with the increase of sediment load. Levels of sediment load in 0, 10, 25, 50, 75, 90, and 100 % reduced detachment rate in rates of 0, 18.93, 36.36, 56.28, 70.15, 83.42, and 92.19 %, respectively. The response relationship of detachment rate to sediment load by Rill flow was described well by a negative linear equation (R 2 range from 0.8489 to 0.9982, P < 0.01), and the vertical and horizontal intercepts of the linear equation represented the detachment and transport capacities, respectively (R 2 = 0.9955, NSE = 0.9788 for D c ; R 2 = 0.9957, NSE = 0.9635 for T c ), as expressed by the WEPP Rill Erosion equation. The WEPP Rill Erosion equation predicted the soil detachment rate very well (R 2 = 0.9667, NSE = 0.9611). Sediment load transported by Rill flow has a negative influence on soil detachment rate in Rills. Introducing sediment load as a factor in model equation of detachment is essential for developing an accepted Erosion model. The WEPP Rill Erosion equation could correctly reflect the response relationship of detachment rate to sediment load in this flume experiment and has a good applicability to loess material.
Gang Liu - One of the best experts on this subject based on the ideXlab platform.
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understanding Erosion processes using rare earth element tracers in a preformed interRill Rill system
Science of The Total Environment, 2018Co-Authors: Xunchang J Zhang, Gang Liu, Fenli ZhengAbstract:Tracking sediment source and movement is essential to fully understanding soil Erosion processes. The objectives of this study were to identify dominant Erosion process and to characterize the effects of upslope interRill Erosion on downslope interRill and Rill Erosion in a preformed interRill-Rill system. A coarse textured soil with 2% clay and 20% silt was packed into a physical model of a scaled small watershed, which was divided into eight topographic units and was tagged with eight rare earth element (REE) oxides. Three 30-min rains were made at the sequential intensities of 60, 90, and 120mmh-1, and runoff and sediment were collected every 2min at the outlet. REE concentration in sediment was measured and used to estimate source contributions after fine-enrichment correction. Results showed that interRill Erosion rate and sediment concentration increased with downslope distance, indicating that sediment transport might have controlled interRill Erosion rates. In contrast, Rill Erosion rate was limited by Rill detachment and development process. Rill Erosion contributed most soil loss; however, the proportion decreased from 78 to 61% as rainfall intensity increased and Rill network matured over three rains. InterRill Erosion was more sensitive than Rill Erosion to rainfall intensity increases. The former was mostly affected by rainfall intensity in this experimental setup, while the latter was controlled by flow discharge, gradient, and Rill evolution stage. The greatest sediment concentration and delivery rate occurred in the stage of the fastest Rill development. The increased sediment delivery from interRill areas appeared to suppress Rill detachment by concentrated flow. This study enhanced our understanding of interRill and Rill Erosion processes and provided the scientific insights for improving soil Erosion models.
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Understanding Erosion processes using rare earth element tracers in a preformed interRill-Rill system
'Elsevier BV', 2018Co-Authors: Xun-chang Zhang, Fenli Zheng, Gang Liu, Liu, Author), Northwest A&f Univ, Inst Soil Water Conservat, 26 Xinong Rd, Yangling 712100, Shaanxi, China.Abstract:Tracking sediment source and movement is essential to fully understanding soil Erosion processes. The objectives of this study were to identify dominant Erosion process and to characterize the effects of upslope interRill Erosion on downslope interRill and Rill Erosion in a preformed interRill-Rill system. A coarse textured soil with 2% clay and 20% silt was packed into a physical model of a scaled small watershed, which was divided into eight topographic units and was tagged with eight rare earth element (REE) oxides. Three 30-min rains were made at the sequential intensities of 60, 90, and 120 ram h(-1), and runoff and sediment were collected every 2 min at the outlet. REE concentration in sediment was measured and used to estimate source contributions after fine-enrichment correction. Results showed that interRill Erosion rate and sediment concentration increased with downslope distance, indicating that sediment transport might have controlled interRill Erosion rates. In contrast, Rill Erosion rate was limited by Rill detachment and development process. Rill Erosion contributed most soil loss; however, the proportion decreased from 78 to 61% as rainfall intensity increased and Rill network matured over three rains. InterRill Erosion was more sensitive than Rill Erosion to rainfall intensity increases. The former was mostly affected by rainfall intensity in this experimental setup, while the latter was controlled by flow discharge, gradient, and Rill evolution stage. The greatest sediment concentration and delivery rate occurred in the stage of the fastest Rill development. The increased sediment delivery from interRill areas appeared to suppress Rill detachment by concentrated flow. This study enhanced our understanding of interRill and Rill Erosion processes and provided the scientific insights for improving soil Erosion models. (C) 2018 Elsevier B.V. All rights reserved
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using beryllium 7 to monitor the relative proportions of interRill and Rill Erosion from loessal soil slopes in a single rainfall event
Earth Surface Processes and Landforms, 2011Co-Authors: Mingyi Yang, Puling Liu, Gang Liu, D N Warrington, Junliang TianAbstract:Quantifying the relative proportions of soil losses due to interRill and Rill Erosion processes during Erosion events is an important factor in predicting total soil losses and sediment transport and deposition. Beryllium-7 ((7)Be) can provide a convenient way to trace sediment movement over short timescales providing information that can potentially be applied to longer-term, larger-scale Erosion processes. We used simulated rainstorms to generate soil Erosion from two experimental plots (5 m 4 m; 25 degrees slope) containing a bare, hand-cultivated loessal soil, and measured (7)Be activities to identify the Erosion processes contributing to eroded material movement and/or deposition in a flat area at the foot of the slope. Based on the mass balance of (7)Be detected in the eroded soil source and in the sediments, the proportions of material from interRill and Rill Erosion processes were estimated in the total soil losses, the deposited sediments in the flat area, and in the suspended sediments discharged from the plots. The proportion of interRill eroded material in the discharged sediment decreased over time as that of Rill eroded material increased. The amount of deposited material was greatly affected by overland flow rates. The estimated amounts of Rill eroded material calculated using (7)Be activities were in good agreement with those based on physical measurements of total plot Rill volumes. Although time lags of 45 and 11 minutes existed between detection of sediment being removed by Rill Erosion, based on (7)Be activities, and observed Rill initiation times, our results suggest that the use of (7)Be tracer has the potential to accurately quantify the processes of Erosion from bare, loessal cultivated slopes and of deposition in flatter, downslope areas that occur in single rainfall events. Such measurements could be applied to estimate longer-term Erosion occurring over larger areas possessing similar landforms. Copyright (C) 2010 John Wiley & Sons, Ltd.
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using 7be to trace temporal variation of interRill and Rill Erosion on slopes
Procedia environmental sciences, 2011Co-Authors: Gang Liu, Qiong Zhang, Mingyi YangAbstract:Abstract Understanding the processes of Erosion-transport-deposition of sediments is necessary to develop more effective soil Erosion prediction models. In this study, Beryllium-7 (7Be) was used as a tracer to describe the dynamics of soil Erosion during a simulated rainfall event on outdoor cultivated plots. The quantitative results of interRill and Rill Erosion on slopes are discussed in this paper. And the calculated results using 7Be tracer are in good agreement with the measured ones. Therefore, 7Be tracer could accurately quantify the processes of Erosion on the cultivated slope.
