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Changes in sediment transport in the Kuye River in the Loess Plateau in China

International Journal of Sediment Research 2009年第2期24卷 201-213页

作者： Jueyi SUI1,Yun HE2,and Cheng LIU3 1 Associate Professor,Environmental Engineering Program,University of Northern British Columbia,Prince George,BC,Canada,V2N 4Z9 2 Senior Engineer,China Institute of Water Resources and Hydropower Research,No. A-1,Fuxing Rd.,Beijing 100038,China Ph.D 3 International Research and Training Center on Erosion and Sedimentation,20 Chegongzhuang West Rd.,Beijing 100048,China Ph.D,Prof. Environmental Engineering Program University of Northern British Columbia Prince George BC Canada V2N 4Z9 China Institute of Water Resources and Hydropower Research No. A-1 Fuxing Rd. Beijing 100038 China International Research and Training Center on Erosion and Sedimentation 20 Chegongzhuang West Rd. Beijing 100048 China

In this paper,the changes in sediment transport over 51 years from 1955 to 2006 in the Kuye River in the Loess Plateau in China are assessed. Key factors affecting sediment yield and sediment transport,such as precipitation depth,discharge,and human activities are studied. To investigate the changes in sediment yield in this watershed,a trend analysis on sediment concentration,precipitation depth,and discharge is conducted. Precipitation depths at 2 Climate Stations(CSs) ,as well as discharge and sediment transport at 3 Gauging Stations(GSs) are used to assess the features of sediment transport in the Kuye River. The runoff modulus(defined as the annual average discharge per unit area,L/(s.km2) ) and the sediment transport modulus(defined as the annual suspended sediment transport per unit area,t/(yr km2) ) are introduced in this study to assess the changes in runoff and sediment yield for this watershed. The results show that the highest average monthly discharge during the study period in the Kuye River is 66.23 m3/s in August with an average monthly sediment concentration of 88.9 kg/m3. However,the highest average monthly sediment concentration during the study period in the Kuye River is 125.34 kg/m3 and occurs in July,which has an average discharge of 42.6 m3/s that is much less than the average monthly discharge in August. It is found that both the runoff modulus and sediment transport modulus at Wenjiachuan GS on the Kuye River has a clear downward trend. During the summer season from July to August,the sediment transport modulus at Wenjiachuan GS is much higher than those at Toudaoguai and Longmen GSs on the Yellow River. The easily erodible loess in the Kuye River watershed and the sparse vegetation are responsible for the extremely high sediment yield from the Kuye River watershed. The analyses of the grain size distribution of suspended load in the Kuye River are presented. The average monthly median grain size of suspended load in the Kuye River is largest in February and then decreases until June. In

关键词： Grain size distribution Kuye River Loess Plateau Precipitation Runoff modulus Sediment transport modulus Soil erosion Yellow River

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Deriving the slope-mean shielded astronomical solar radiation spectrum and slope-mean possible sunshine duration spectrum over the Loess Plateau

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Journal of Mountain Science 2020年第1期17卷 133-146页

作者： CHEN Nan Key Laboratory of Spatial Data Mining & Information Sharing Ministry of Education Fuzhou University Spatial Information Research Center of Fujian Province Fuzhou University

Solar radiation is often shielded by terrain relief, especially in mountainous areas, before reaching the surface of the Earth. The objective of this paper is to study the spatial structures of the shielded astronomical solar radiation(SASR) and the possible sunshine duration(PSD) over the Loess Plateau. To this end, we chose six test areas representing different landforms over the Loess Plateau and the software package of Matlab was used as the main computing platform. In each test area, 5-m-resolution digital elevation model established from 1:10,000 scale topographic maps was used to compute the corresponding slope, SASR and PSD. Then, we defined the concepts of the slope-mean SASR spectrum and the slope-mean PSD spectrum, and proposed a method to extract them from the computed slope, SASR and PSD over rectangular analysis windows. Using this method, we found both spectrums in a year or in a season for each of the four seasons in the six test areas. Each spectrum was found only when the area of the corresponding rectangular analysis window was greater than the corresponding stable area of the spectrum. The values of the two spectrums decreased when the slope increased.Furthermore, the values of the stable areas of the spectrums in a year or in a season were positively correlated with the variable coefficients of the slope or the profile curvature. The values of the stable areas of the two spectrums in a year or in a season may represent the minimum value of test areas for corresponding future research on the spatial structures of the SASR or PSD. All the findings herein suggest that the spatial structures of the PSD and the SASR are caused by the interactions between solar radiation and terrain relief and that the method for extracting either spectrum is effective for detecting their spatial structures. This study may deepen our understanding of the spatial structure of solar radiation and help us further explore the distribution of solar energy in mountainous regions.

关键词： Digital elevation model Shielded extraterrestrial solar radiation Spectrum Possible Sunshine duration Slope Loess Plateau

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Nutrients of green and senesced leaves of a Robinia pseudoacacia plantation along a latitudinal gradient on the Loess Plateau,China

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Journal of Forestry Research 2021年第6期32卷 2499-2506页

作者： Quanchao Zeng Yang Liu Jiajia Yang Yanan Chen Lusha Ma Shaoshan An College of Resources and Environment Huazhong Agricultural UniversityWuhan430070People’s Republic of China State Key Laboratory of Soil Erosion and Dryland Farming On the Loess Plateau Northwest A&F UniversityYangling712100ShaanxiPeople’s Republic of China

Plantations have been widely established to improve ecosystem services and functioning.Black locust,Robinia pseudoacacia L.is a common,widely planted species to control soil erosion on the Loess Plateau.Previous studies have focused on economic values but the interactions between soil and plant carbon(C),nitrogen(N)and phosphorus(P)remain unknown.Investigating variations of soil,green and senesced leaf C,N and P levels in R.pseudoacacia along a latitudinal gradient is useful to understanding its ecological functions.The results show that soil C,N and senesced leaf N and P significantly decreased with an increase in latitude,but there were no significant changes in the senesced leaf C and soil P.The resorption efficiency of N was related with latitude and soil N levels,and the relation between green leaf N and soil N was significant.These relations suggest that soil N was the key in affecting green leaf N levels.At higher latitudes,senesced leaves had lower N levels associated with higher N resorption efficiency to maintain a stable N content in green leaves.With a decrease of soil N,R.pseudoacacia can enhance N resorption efficiency to meet the demand of growth.Thus,it is an important species for reforestation,especially in nutrient-poor environments.

关键词： Green leaves Senesced leaves Resorption efficiency Robinia pseudoacacia Loess Plateau Vegetation restoration

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Characteristics and influencing factors of proximity distance index on the northern Shaanxi Loess Plateau in China

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Journal of Mountain Science 2019年第12期16卷 2844-2855页

作者： ZHOU Yi LEI Xue YANG Feng LI Yang WANG Bin School of Geography and Tourism Shaanxi Normal UniversityXVan 710062China State Key Laboratory of Remote Sensing Science Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China

Topographic feature points and lines are the framework of topography,and their spatial distance relationship is an breakthrough in the study of topographical geometry,internal structure and development level.Proximity distance(PD)is an indicator to describe the distance between the gully source point(GSP)and the watershed boundary.In the upstream catchment area,PDs can be expressed by the streamline proximity distance(SPD),as well as by the horizontal proximity distance(HPD)and the vertical proximity distance(VPD)in the horizontal and vertical dimensions,respectively.The series of indicators(e.g.,SPD,HPD and VPD)are important for quantifying the geomorphological development process of a loess basin because of the headward erosion of loess gullies.In this study,the digital elevation model data with 5 m resolution and a digital topographic analysis method are used for the statistical analyses of the SPD,VPD and HPD in 50 sample areas of 6 geomorphic types in the Loess Plateau of northern Shaanxi.The spatial characteristics and the influencing factors are also analysed.Results show that:1)Central tendencies for the HPDs and the VPDs for the whole study area and the six typical loess landforms are evident.2)Spatial patterns of the HPDs and the VPDs exhibit evident trends and zonal distributions over the whole study area.3)The HPDs have a strong positive correlation with gully density(GD)and hypsometric integral.The VPDs also correlates with GD to an extent.Vegetation cover,mean annual precipitation and loess thickness have stronger effects on the VPD than on the HPD.

关键词： Digital elevation model(DEM) Proximity distance Terrain factor Digital terrain analysis Loess Plateau

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Study on adverse effects of groundwater level rising induced by land creation engineering in hilly and gully area of the Loess Plateau

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Journal of Mountain Science 2019年第12期16卷 2739-2753页

作者： DUAN Xu DONG Qi YE Wan-jun ZHOU Jia-lin OH Erwin School of Architectural and Civil Engineering Xi'an University of Science and TechnologyXi'anShaanxi 710054China Shaanxi Science&Technology Holding Group Co. Ltd.Xi'anShaanxi 710054China State Key Laboratoiij for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'an 710049China School of Engineering Griffith UniversityGold Coast 7222Australia

Land creation projects have been implemented in China to expand urban space in mountainous areas.In addition to the predictable settlement brought about by filling construction,varying degrees of land subsidence and engineering failures have a demonstrated relationship to groundwater level fluctuation induced by land creation engineering.In this work,we adopted a typical large-scale land creation project,Yan’an New City in Shaanxi province,West China,as our study area.Prior to conducting the main experiment,preliminary field investigation and groundwater level monitoring were conducted to determine the groundwater fluctuation trend induced by land creation engineering.Although a blind drainage system was implemented,the depth aspect of groundwater level changes after large-scale land creation still needed to be addressed.To study the degree of impact and the settlement mechanism induced by the rising groundwater level,we conducted a Water Immersion Test(WIT)in a typical land creation site for 107 days.The rising groundwater level was simulated by injecting water from the bottom of the filling foundation.During the WIT,the soil water content,surface subsidence,and internal settlement of soil at different depths were obtained.Surface subsidence development could be categorized into four stages during the water level increase.The second stage,which is defined as the point when the groundwater level rises to 10 m,marked the critical point in the process.Furthermore,it was ascertained that the local settlement in regions that were originally composed of steep slopes is larger than that in originally flat areas.In addition,ground cracks and sinkholes in the study area were inspected;and it was determined that they would become new channels that would accelerate water infiltration and exacerbate the settlement.Based on the results from our field investigation and testing,several suggestions are proposed for land creation projects to mitigate issues associated with construction-induced groundwater level rising.

关键词： Water immersion test Land creation engineering Loess Plateau Groundwater Subsidence

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Agricultural sustainability in a sensitive environment——a case analysis of Loess Plateau in China

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Journal of Environmental Sciences 2002年第3期14卷 357-366页

作者： KongZH ZhangXS TheLaboratoryofQuantitativeVegetationEcology TheInstituteofBotanyChineseAcademyofSciencesBeijin100093China.E－mail：zhkong@*** TheLaboratoryofQuantitativeVegetationEcology TheInstituteofBo

Loess Plateau, an arid and semi arid region in Northwest China, is well known for its most serious soil erosion in terms of sediment yield each year. Soil erosion, which is intensified by agricultural activities, is the major factor influencing sustainable agriculture development in this region. It reduces productivity by removing nutrients and especially reducing water availability that is essential for crop production in the area. It also brings about off site costs by demanding more efforts for maintenance of banks and dams along Yellow River through raising the riverbed with sediment. Climate is capricious and extreme weather conditions occur frequently, which impairs normal agricultural production with erosion and also decrease of water availability. Extensive way of farming still dominates on the Loess Plateau, which cannot produce satisfying economic results and needs to be improved or altered. Conventional agricultural production pattern needs to be reconsidered for husbandry has not been granted its due position. Agriculture is the backbone of economy. Poor agricultural production impedes economic development and vice versa, backward economy also influences the advancement of agriculture. Besides a large population, education status of farmers is another threshold that requires being resolved for a sustainable agriculture. Although conventional agriculture has been practiced there for more than 5000 years, now it cannot meet the demand for food and fiber by the increasing population and some of its farming practices are contributing to environmental degradation directly or indirectly and can sustain no longer. Agriculture on Loess Plateau needs to find its own way of sustainability. To work toward a sustainable agriculture, chances and challenges both indwell on Loess Plateau.

关键词： Loess Plateau sustainable agriculture soil erosion water erosion conservation practice

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An Overview of the Semi-arid Climate and Environment Research Observatory over the Loess Plateau

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Advances in Atmospheric Sciences 2008年第6期25卷 906-921页

作者：黄建平张武左金清闭建荣史晋森王鑫常倬林黄忠伟杨溯张北斗王国印冯广泓袁九毅张镭左洪超王式功符淙斌丑纪范 College of Atmospheric Sciences Lanzhou University Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA) Institute of Atmospheric Physics Chinese Academy of Sciences

Arid and semi-arid areas comprise about 30% of the earth＇s surface. Changes in climate and climate variability will likely have a significant impact on these regions. The Loess Plateau over Northwest China is a special semi-arid land surface and part of a dust aerosol source. To improve understanding and capture the direct evidence of the impact of human activity on the semi-arid climate over the Loess Plateau, the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL） was established in 2005. SACOL consists of a large set of instruments and focuses on：（1） monitoring of long term tendencies in semiarid climate changes; （2） monitoring of the aerosol effect on the water cycle; （3） studies of interaction between land surface and the atmosphere; （4） improving the land surface and climate models; and （5） validation of space-borne observations. This paper presents a description of SACOL objectives, measurements, and sampling strategies. Preliminary observation results are also reviewed in this paper.

关键词： cloud aerosol land surface semi-arid Loess Plateau SACOL

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Transforming the Loess Plateau of China

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Frontiers of Agricultural Science and Engineering 2016年第3期3卷 181-185页

作者： Yuheng LI Guoming DU Yansui LIU Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences College of Resources and Environment Northeast Agricultural University College of Resources Science and Technology Beijing Normal University

This paper aims to show the importance of land consolidation in transforming the Loess Plateau of China. The paper comprehensively analyzes how over recent decades the Grain for Green Project and Gully Land Consolidation Project jointly transformed the ecology and landscape of the Loess Plateau and the livelihood of its residents. The findings show that these two projects have achieved a balance between green protection, new land creation, and improved food security and livelihood of local people in the hilly areas of China. The paper points out that the successful transformation of the plateau lies in a holistic approach incorporating various components of the human and natural systems. Finally, the paper highlights the necessity of retaining these two land consolidation projects as part of an ongoing policy in the mountain and hilly areas of China, changing agricultural management to suit the new relationship between humans and the land.

关键词： China critical zone land consolidation Loess Plateau sustainability

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Analysis of Patterns and Benefits of Cultivated Land Transfer in Rural Areas in the Loess Plateau——A Case Study of Yuanzhou District of Ningxia

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Asian Agricultural Research 2016年第10期8卷 59-65页

作者： Xiaoyi SUN Yong XU Qing TANG Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences University of Chinese Academy of Sciences

Cultivated land transfer is one of hotspots in research on agriculture,rural areas and farmers in China. Based on research achievements related to cultivated land transfer and the field survey of Yuanzhou District in the Loess Plateau,the primary patterns of cultivated land transfer in rural areas in the Loess Plateau were summarized according to the management subjects of cultivated land. According to the analyses of family income and expenses of a peasant household,the benefit of various patterns of cultivated land transfer to increase farmers' income was analyzed,and the social and ecological benefits of cultivated land transfer were assessed. The results showed that cultivated land transfer had developed rapidly in the Loess Plateau,and 42. 5% of the investigated peasant households took part in cultivated land transfer. The benefit of cultivated land transfer to increase farmers' income was obvious after cultivated land transfer. There were significant differences between various patterns of cultivated land transfer in the increase of farmers' income. The pattern driven by agricultural cooperatives increased farmers' income most obviously,and the annual family earnings per peasant household reached 12072. 99 yuan / a. The social and ecological benefits of cultivated land transfer conducted by peasant households spontaneously were very remarkable. The pattern led by leading enterprises promoted the large-scale operation of cultivated land greatly,but its benefit to increase farmers' income was limited. The comprehensive benefit of the pattern guided by the government was the most balanced. Geographic environment had decisive influences on the choose of patterns of cultivated land transfer in the Loess Plateau.

关键词： Loess Plateau Cultivated land transfer Patterns Benefit Yuanzhou District of Ningxia

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Seasonal Variation of Moisture Availability at Water-wind Erosion Crisscross Region in Northern Loess Plateau China

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Journal of Northeast Agricultural University(English Edition) 2013年第4期20卷 72-77页

作者： Tan Lu Wang Zhong-bo Huang Jin-bai Yasuda Hiroshi College of Water Conservancy and Civil Engineering Northeast Agricultural University Arid Land Research Center Tottori University

The objectives of the current study were to estimate evapotranspiration（ET） over the grassland and assess seasonal variation of moisture availability at the wind-water erosion crisscross region in the northern Loess Plateau of China. The Liudaogou Catchment which has the representative climatic and hydrological characteristics of the wind-water erosion crisscross region was chosen as the study location. The reference crop evapotranspiration（ET 0） was estimated by Penmen method, which was recommended by FAO56 and the evapotranspiration over the grassland（ET） was estimated by Penmen-Monteith equation using the observed meteorological data with time unit of 1 h. The soil moisture availability factor was defined by m a =ET/ET 0. The calculated results for 2006 indicated that the total ET 0 was slightly more than the total yearly precipitation and ET accounted for 37 % of that, ET increased distinctly after the intensive rainfall event in the rainy season. Most of the m a was less than 0.4 and its annual mean was 0.34. It was expected that the results provided a basis for studies on dynamic functional analysis of soil moisture, relationship between soil water and crop growth at the wind-water erosion crisscross region in the northern Loess Plateau.

关键词： Loess Plateau Liudaogou Catchment ET ET0 moisture availability

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