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Principal Denudation Processes and Their Contribution to Fluvial Suspended Sediment Yields in the Upper Yangtze River Basin and Volga River Basin

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Journal of Mountain Science 2015年第1期12卷 101-122页

作者： VALENTIN Golosov ZHANG Xin-bao he xiu-bin TANG Qiang ZHOU Ping Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences Faculty of Geography Moscow State University Kazan (Volga region) State University State Key Laboratory of Urban and Regional Ecology Research Center for Ecoenvironment Sciences Chinese Academy of Sciences

This paper synthesized the principal land denudation processes and their role in determining riverine suspended sediment yields(SSY) in two typical geographical environments of the Upper Yangtze River Basin in China and the Volga River Basin in Eastern Europe. In the Upper Yangtze River Basin, natural factors including topography, climate,lithology and tectonic activity are responsible for the spatial variation in the magnitude of denudation *** disturbances have contributed to the temporal changes of soil erosion and fluvial SSY during the past decades. On one hand, land use change caused by deforestation and land reclamation has played an important role in the acceleration of sediment production from the central hilly area and lower Jinsha catchment; On the other hand, diverse soil conservation practices(e.g., reforestation,terracing) have contributed to a reduction of soil erosion and sediment production since the late 1980 *** was difficult to explicitly decouple the effect of mitigation measures in the Lower Jinsha River Basindue to the complexity associated with sediment redistribution within river channels(active channel migration and significant sedimentation). The whole basin can be subdivided into seven sub-regions according to the different proportional inputs of principal denudation processes to riverine SSY. In the Volga River Basin, anthropogenic sheet, rill and gully erosion are the predominant denudation processes in the southern region, while channel bank and bed erosion constitutes the main source of riverine suspended sediment flux in the northern part of the basin. Distribution of cultivated lands significantly determined the intensity of denudation *** relief characteristics also considerably influence soil erosion rates and SSY in the southern Volga River Basin. Lithology, soil cover and climate conditions determined the spatial distribution of sheet, rill and gully erosion intensity, but they play a secondary role in SSY s

关键词： Land denudation Anthropogenicdisturbance Suspended sediment yield UpperYangtze River Volga River

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Soil nutrients in relation to vertical roots distribution in the riparian zone of Three Gorges Reservoir,China

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Journal of Mountain Science 2018年第7期15卷 1498-1509页

作者： ZHONG Rong-hua HU Jin-ming BAO Yu-hai Wang Fei he xiu-bin Yunnan Key Laboratory of International Rivers and Transboundary Eeo-security Kunming 650091 China Institute oflnternational Rivers and Eco-security Yunnan University Kunming 650091 China Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

Since the impoundment of the Three Gorges Reservoir(TGR), the riparian zone has been subjected to numerous environmental changes. This study was conducted to recognize the distribution of grass roots and its impacts on soil nutrients in the water level fluctuation zone of TGR. Roots of four predominant herbaceous plants in the study area, specifically, Cynodon dactylon, hemarthria altissima, hemarthria compressa, and Paspalum paspaloides, and their corresponding relation with soil nutrient contents were investigated. Root surface area density was determined with Win RHIZO, and the relationships of root distribution with soil depths and soil nutrient contents were studied. The results indicates that most roots are distributed in the top soil layer of 0-10 cm. Estimated root surface area density for the selected grass species ranges from 0.16 to 13.44 cm^2/cm^3, and decreases exponentially with an increase in soil depth. Soil organic matter and total nitrogen contents are significantly lower on bare control area than the corresponding values on the grasslands. Total nutrient contents on grasslands of C. dactylon and H. compressa are higher than those of other grass areas. Root length density and root surface area density are significantly correlated with soil organic matter and total nitrogen content for the four grasslands. The present results suggests that plant roots have significant effects on the distribution of soil nutrients in soil profiles in the riparian zone along the TGR. Nevertheless, additional investigations are needed to reveal the specific interactions between plant roots distribution, soil nutrients and water level fluctuations.

关键词： Roots distribution Soil nutrients Water level fluctuations Riparian zone Root surface area density Root length density

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Spatiotemporal variation of the loose deposits in Baisha River Basin after the 2008 Wenchuan earthquake

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Journal of Mountain Science 2022年第9期19卷 2544-2555页

作者： LYU Jiao-rong BAO Yu-hai XIE Hang-yu LI Hong HU Yun-hua he xiu-bin Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China University of the Chinese Academy of Sciences Beijing 100049China The Third Surveying and Mapping Engineering Institute of Sichuan Province Chengdu 610500China

Extensive landslides were triggered by the Wenchuan earthquake(in China)on 12 May 2008,causing a tremendous amount of loose material suspended on the hillslopes,likely to be eroded and transported by *** is of great significance to study the long-term variation of the quantity and spatiotemporal distribution of loose deposits after a great earthquake in order to understand the restoration process,to assess the risk of future soil erosion,including geological hazards,and to further develop ecological governance *** this study,information about the multi-temporal loose deposits on the ranges of the Baisha River Basin,an alpine valley near the epicenter,was extracted by objectoriented remote sensing interpretation,and analysis on their spatiotemporal variation showed that the earthquake in 2008 resulted in loose deposits covering an additional area of 81.09 km2,with a volume estimated at 0.357 billion *** five years after the earthquake,the vegetation had recovered rapidly,and the extent of the deposits was significantly *** 5 to 13 years after the earthquake,the vegetation continued to recover but at a slower rate and a decreasing trend in newly formed deposits was *** total area,volume and quantity of the loose deposits gradually *** geometric mean center of the loose deposits gradually moved back towards the upstream area after the earthquake and,by 2021,the mean center was about 4 km away from its pre-earthquake *** the mean center of the loose deposits in 2008 as the center,the deposits in the downstream area shrank significantly after the earthquake,but collapses and landslides of deposits persisted in the upstream area to the west-southwest,west-northwest and northnorthwest from the mean center,indicating future source areas of new loose deposits in the basin.

关键词： Wenchuan earthquake Loose deposits earthquake-triggered disaster Soil erosion Remote sensing

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Dry cropland changes in China's Three Gorges Reservoir Region during the period 1990 to 2015

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Journal of Mountain Science 2020年第3期17卷 516-527页

作者： WANG Ming-feng TIAN Feng-xia he xiu-bin Raheel ANJUM BAO Yu-hai Adrian LCOLLINS Key Laboratory of Mountain Surface Process and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Department of Tourism and Geography Tongren UniversityTongrenGuizhou Province554300China Abdul Wali Khan University MardanPakistan Sustainable Agriculture Sciences Department Rothamsted ResearchNorth WykeOkehamptonDevon EX202SBUK

Monitoring and analyzing changes in the extent of cultivated land may inform strategic decisions on issues of environmental and food *** dry cropland area of 12000 km^2in the Three Gorges Reservoir Region(TGRR)of China is essential for feeding the local population of^20 million,but is highly prone to soil erosion,leading to the delivery of excessive amounts of sediment and associated pollutants to the Three Gorges Reservoir(TGR),and causing serious eco-environmental *** this background,this paper used Landsat images and a digital elevation model to analyze the altitudinal distribution of,and dynamic changes in,the area of dry cropland during the period 1990 to *** results suggest that dry cropland was mainly distributed in the elevation range of 200-600 *** dry cropland area decreased from 12525.37 km^2to 11796.27 km^2during the 25-year study period,including a particularly significant decrease in the rate of decrease from 6.93 km^2/yr to 43.99 km^2/yr after *** largest decline in the dry cropland area occurred in the elevation range of 600-900 *** transformations between dry cropland and forest revealed the impact of the TGR operation on the extent of dry cropland.A total of 528.79 km^2of dry cropland with slopes>25°were converted to forest after 2000,whereas a total of 642 km^2of forest was converted to dry cropland during the study period,and these conversions mainly occurred between the elevation of 200–900 *** spatiotemporal changes in the dry cropland area are likely to raise new issues concerning food security in the TGRR.

关键词： Dry cropland Altitude Reservoir operation Three Gorges Reservoir Region Landuse change Soil erosion

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Fractal characterization of sediment particle-size distribution in the water-level fluctuation zone of the Three Gorges Reservoir, China

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Journal of Mountain Science 2019年第9期16卷 2028-2038页

作者： LI Jin-lin BAO Yu-hai WEI Jie he xiu-bin TANG Qiang Jean de Dieu NAMBAJIMANA Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Chongqing Key Laboratory of Earth Surface Processes and Environmental Remote Sensing in the Three Gorges Reservoir Area Chongqing 401331 China University of Chinese Academy of Sciences Beijing 100049 China Sustainable Agriculture Sciences Department Rothamsted Research North Wyke Okehampton Devon EX20 2SB UK

The combined effect of periodic water impoundment and seasonal natural flood events has created a 30 m high water-level fluctuation zone(WLFZ) around the Three Gorges Reservoir(TGR), China, forming a unique eco-landscape. Siltation, eutrophication, enrichment of heavy metals, and methane emissions in the WLFZ have been widely associated with sediment and soil particles generated from the upstream catchment or upland slopes. However, little attention has been paid to the complexity of sediment particle-size distributions in the WLFZ. In the present study, core samples(from a 345 cm thick sediment core from the base of the WLFZ), slope transect surface samples(across/up a WLFZ slope), and along-river/longitudinal surface samples(from the reservoir reaches) were collected. Laser granulometry and a volume-based fractal model were used to reveal the characteristics of sediment particle-size distributions. Results indicate that the alternation of coarse and fine particles in the sedimentary core profile is represented as a fluctuation of low and high values of fractal dimension(D), ranging from 2.59 to 2.77. On the WLFZ slope transect, surface sediment particles coarsen with increasing elevation, sand content increases from 3.3% to 78.5%, and D decreases from 2.76 to 2.53. Longitudinally, surface sediments demonstrate a downstream-fining trend, and D increases gradually downstream. D is significantly positively correlated with the fine particle content. We conclude that D is a useful measure for evaluating sediment particle-size distribution.

关键词： Spatial differentiation Sediment particle Fractal dimension Water-level fluctuation zone Three Gorges Reservoir

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Assessing Soil Erosion Rates on Manually-Tilled Hillslopes in the Sichuan Hilly Basin Using ^(137)Cs and ^(210)Pb_(ex) Measurements

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Pedosphere 2007年第3期17卷 273-283页

作者： ZheNG Jin-Jun he xiu-bin D. WALLING ZHANG Xin-Bao D. FLANAGAN QI Yong- Qing Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 （China） Graduate University of the Chinese Academy of Sciences Beijing 100049 （China） Department of Geography University of Exeter Exeter EX4 4RJ （UK） State Key laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of SciencesXi＇an 710075 （China） USDA-ARS National Soil Erosion Research Laboratory West Lafayette Indiana 47907 （USA） Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101（China）

Purple soils are widely distributed in the Sichuan Hilly Basin and are highly susceptible to erosion, especially on the cultivated slopes. Quantitative assessment of the erosion rates is, however, difficult due to small size of the plots of the manually-tilled land, the complex land use, and steep hillslopes. ^137Cs and ^210Pbex （excess ^210Pb） tracing techniques were used to investigate the spatial pattern of soil erosion rates associated with slope-land under hoe tillage in Neijiang of the Sichuan Hilly Basin. The ^137Cs and ^210Pbex inventories at the top of the cultivated slope were extremely low, and the highest inventories were found at the bottom of the cultivated slope. By combining the erosion rates estimates provided by both ^137Cs and 21~Pbex measurements, the weighted mean net soil loss from the study slope was estimated to be 3 100 t km^-2 year^-1, which was significantly less than 6 930 t km^-2 year^-1 reported for runoff plots on a 10° cultivated slope at the Suining Station of Soil Erosion. The spatial pattern of soil erosion rates on the steep agricultural land showed that hoe tillage played an important role in soil redistribution along the slope. Also, traditional farming practices had a significant role in reducing soil loss, leading to a lower net erosion rate for the field.

关键词： ^137Cs hoe tillage, ^210Pbex purple soil soil erosion

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Interpreting sedimentation dynamics at Longxi catchment in the Three Gorges Area,China,using Cs-137 activity,particle size and rainfall erosivity

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Journal of Mountain Science 2016年第5期13卷 857-869页

作者： GAO Jin-zhang LONG Yi ZHANG Xin-bao Collins Adrian L he xiu-bin ZHANG Yun-qi SHI Zhong-lin Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Sustainable Soils and Grassland Systems Department Rothamsted ResearchNorth WykeOkehamptonDevon EX20 2SBUK Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection Linyi UniversityLinyi 276005China

Reservoir sedimentation dynamics were interpreted using Cs-137 activity, particle size and rainfall erosivity analysis in conjunetion with sediment profile coring. Two sediment cores were retrieved from the Changshou reservoir of Chongqing, which was dammed in 1956 at the outlet of Longxi catchment in the Three Gorges Area using a gravity corer equipped with an aerylie tube with an inner diameter of 6 em. The extracted cores were sectioned at 2 cm intervals. All sediment core samples were dried, sieved （〈2 mm） and weighed. 137Cs activity was measured by y-ray spectrometry. The particle size of the core samples was measured using laser particle size granulometry. Rainfall erosivity was calculated using daily rainfall data from meteorological records and information on soil conservation history was collated to help interpret temporal sedimentation trends. The peak fallout of 137Cs in 1963 appeared at a depth of 84 cm in core A and 56 cm in core B. The peaks of sand contents were related to the peaks of rainfall erosivity which were recorded in 1982, 1989, 1998 and 2005, respectively. Sedimentation rates were calculated according to the sediment profile chronological controls of 1956, 1963, 1982, 1989, 1998 and 2oo5. The highest sedimentation rate was around 2.0 cm·a^-1 between 1982 and 1988 when the Chinese national reform and the Household Responsibility System were implemented, leading to accelerated soil erosion in the Longxi catchment. Since 1990s, and particularly since 2005, sedimentation rates clearly decreased, since a number of soil conservation programs have been carried out in the catchment. The combined use of ^137Cs chronology, particle size and rainfall erosivity provided a simple basis for reconstructing reservoir sedimentation dynamics in the context of both physical processes and soil restoration. Its advantages include avoiding the need for full blown sediment yield reconstruction and the concomitant consideration of core correlation and corrections

关键词： Sedimentation Cesium-137 Particle size Rainfall erosivity Soil erosion Three Gorges Area

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Estimation of soil reinforcement by the roots of four postdam prevailing grass species in the riparian zone of Three Gorges Reservoir, China

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Journal of Mountain Science 2016年第3期13卷 508-521页

作者： ZHONG Rong-hua he xiu-bin BAO Yu-hai TANG Qiang GAO Jin-zhang YAN Dan-dan WANG Ming-feng LI Yu Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-environmental SciencesChinese Academy of SciencesBeijing 100085China

Soil erosion and bank degradation is a major post-dam concern regarding the riparian zone of the Three Gorges Reservoir. The development and succession of vegetation is a main countermeasure,especially to enhance bank stability and mitigate soil erosion by the root system. In this study, the roots of four prevailing grass species, namely, Cynodon dactylon, hemarthria altissima, hemarthria compressa, and Paspalum paspaloides, in the riparian zone were investigated in relation to additional soil cohesion. Roots were sampled using a single root auger. Root length density（RLD） and root area ratio（RAR） were measured by using the Win RHIZO image analysis system. Root tensile strength（TR） was performed using a manualdynamometer, and the soil reinforcement caused by the roots was estimated using the simple Wu＇s perpendicular model. Results showed that RLD values of the studied species ranged from 0.24 cm/cm3 to20.89 cm/cm3 at different soil layers, and RLD were significantly greater at 0–10 cm depth in comparison to the deeper soil layers（＆gt;10 cm）. RAR measurements revealed that on average 0.21% of the reference soil area was occupied by grass roots for all the investigated species. The measured root tensile strength was the highest for P. paspaloides（62.26MPa） followed by C. dactylon（51.49 MPa）, ***（50.66 MPa）, and H. altissima（48.81MPa）. Nevertheless, the estimated maximum root reinforcement in this investigation was 22.5 k Pa for *** followed by H. compressa（21.1 k Pa）, ***（19.5 k Pa）, and C. dactylon（15.4 k Pa） at0–5 cm depth soil layer. The root cohesion values estimated for all species were generally distributed at the 0–10 cm depth and decreased with the increment of soil depth. The higher root cohesion associated with H. altissima and H. compressa implies their suitability for revegetation purposes to strengthen the shallow soil in the riparian zone of the Three Gorges Reservoir. Although the soil reinforcement induced by roots is only as

关键词： Bank stabilization Root area ratio Root tensile strength Soil reinforcement Riparian zone Three Gorges Reservoir

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Effects of seasonal water-level fluctuation on soil pore structure in the Three Gorges Reservoir,China

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Journal of Mountain Science 2018年第10期15卷 2192-2206页

作者： ZHANG Shu-juan TANG Qiang BAO Yu-hai he xiu-bin TIAN Feng-xia LüFa-you WANG Ming-feng Raheel ANJUM Key Laboratory of Mountain Surface Process and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Sustainable Agriculture Sciences Department Rothamsted ResearchNorth WykeOkehamptonDevonEX202SBUK Abdul Wali Khan University Mardan 23200Pakistan

Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrial X-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity(? 100 ?m), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat numberwithin each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.

关键词： Soil pore structure X-ray computed tomography Image analysis Wetting and drying cycles Water-level fluctuation Three Gorges

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玉米秸秆-轮胎钢丝混杂纤维混凝土的抗压性能和抗冻性能研究

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辽宁工业大学学报（自然科学版） 2024年第2期44卷 100-104页

作者：王端阳毕重何秀彬张恩涛任莉莉辽宁工业大学土木建筑工程学院锦州121001 辽宁铁道职业技术学院铁道工程学院锦州121001

通过在混凝土中添加不同掺量的玉米秸秆纤维和轮胎刚丝纤维,分析了玉米秸秆纤维和废旧轮胎钢丝纤维的掺量对混凝土7 d和28 d的立方体抗压强度的影响,同时也进行了抗冻性试验。研究表明:在适量的纤维掺量下,玉米秸秆纤维和轮胎钢丝纤维... 详细信息

通过在混凝土中添加不同掺量的玉米秸秆纤维和轮胎刚丝纤维,分析了玉米秸秆纤维和废旧轮胎钢丝纤维的掺量对混凝土7 d和28 d的立方体抗压强度的影响,同时也进行了抗冻性试验。研究表明:在适量的纤维掺量下,玉米秸秆纤维和轮胎钢丝纤维对混凝土7 d和28 d的立方体抗压强度都具有提升效果,最优组掺量为0.6%的玉米秸秆纤维,1.0%的轮胎钢丝纤维,抗压强度分别比基准组提高了8.78%和15.92%;两种纤维的掺入也提高了混凝土的抗冻性,最优组较基准组在冻融循环25、50、75次时的损失率分别降低3.63%、4.46%、7.31%。

关键词：纤维混凝土玉米秸秆纤维轮胎钢丝纤维抗压强度抗冻性能

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