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Changes in Soil Hot-Water Extractable C,N and P Fractions During Vegetative Restoration in Zhifanggou Watershed on the Loess Plateau

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Journal of Integrative Agriculture 2013年第12期12卷 2250-2259页

作者： UE Sha LI Peng LIU Guo-bin LI Zhan-bin ZHANG Chao State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau of Northwest A&F University Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry Water Resources Key Laboratory of Northwest Water Resources and Environment Ecology Ministry of Education/Xi’an University of Technology

The study was conducted in Zhifanggou Watershed,Shaanxi Province,China,to evaluate the effect of different vegetation types on hot-water extractable C,N and P fractions,with the aim to determine whether hot-water extractable fractions could be used as indicators of soil quality change in Loess Plateau.The six vegetation types established in 1975 were（i） Robinia pseudoacacia L.,（ii） Caragana korshinkii Kom.,（iii） Pinus tabulaeformis Carr.,（iv） P.tabulaeformis-Amorpha fruticosa L.,（v） R.pseudoacacia-A.fruticosa,and（vi） grassland.A cropped hillslope plot and a Platycladus orientalis L.native forest plot were used as references.The results indicated that the conversion of native forest to cropland resulted in a significant decline in the hot-water extractable C,N and P fractions.Hot-water extractable C,N,and P increased when cultivated land was revegetated,but after 30 years the amount of hot-water extractable C,N,and P in revegetated fields was still much lower compared to native forest.Hot-water extractable fractions increased more under mixed-forest than under pure-forest stands.Furthermore,there was a significant correlation between the hot-water extractable fractions and soil chemical and microbiological properties.The results showed that hot-water extractable fractions could be used as indicators of soil quality change on the Loess Plateau.

关键词： soil hot-water extractable fraction vegetative restoration Loess Plateau

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Fractal features of soil profiles under different land use patterns on the Loess Plateau, China

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Journal of Arid Land 2014年第5期6卷 550-560页

作者： Lie XIAO Sha XUE GuoBin LIU Chao ZHANG State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F University Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources

Fractal theory is becoming an increasingly useful tool to describe soil structure dynamics for a better understanding of the performance of soil systems. Changes in land use patterns significantly affect soil physical, chemical and biological properties. However, limited information is available on the fractal characteristics of deep soil layers under different land use patterns. In this study, the fractal dimensions of particle size distribution（PSD） and micro-aggregates in the 0–500 cm soil profile and soil anti-erodibility in the 0–10 cm soil profile for 10 typical land use patterns were investigated in the Zhifanggou Watershed on the Loess Plateau, China. The 10 typical land use patterns were： slope cropland, two terraced croplands, check-dam cropland, woodland, two shrublands, orchard, artificial and natural grasslands. The results showed that the fractal dimensions of PSD and micro-aggregates were all significantly influenced by soil depths, land use patterns and their interaction. The plantations of shrubland, woodland and natural grassland increased the amount of larger micro-aggregates, and decreased the fractal dimensions of micro-aggregates in the 0–40 cm soil profile. And they also improved the aggregate state and aggregate degree and decreased dispersion rate in the 0–10 cm soil profile. The results indicated that fractal theory can be used to characterize soil structure under different land use patterns and fractal dimensions of micro-aggregates were more effective in this regard. The natural grassland may be the best choice for improving soil structure in the study area.

关键词： fractal dimension anti-erodibility soil profile land use pattern Loess Plateau

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Changes in terrestrial surface dry and wet conditions on the Loess Plateau(China) during the last half century

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Journal of Arid Land 2013年第1期5卷 15-24页

作者： YuBi YAO RunYuan WANG JinHu YANG Ping YUE DengRong LU Guo,Ju XIAO Yang WANG LinChun LIU China Meteorological Administration Key Laboratory of Arid Climate Change and Reducing Disaster Lanzhou 730020 China Gansu Province Key Laboratory of Arid Climate Change and Reducing Disaster Lanzhou 730020 China Lanzhou Institute of'Arid Meteorology China Meteorological Administration Lanzhou 730020 China Meteorological Bureau of Dingxi City Dingxi 743000 China Gansu Meteorological Information Center Lanzhou 730020 China New Technology Application Research and Development Centre of Ningxia University Yinchuan 750021 China

This paper, using a revised Penman-Monteith model, computed the terrestrial surface humidity index of the Loess Plateau （China） based on climatic factors of monthly mean temperature, maximum temperature, minimum temperature, relative humidity, precipitation, wind speed and sunshine duration observed on the plateau from 1961 to 2008. The temporal-spatial distribution, anomaly distribution and sub-regional temporal variations of the terrestrial surface dry and wet conditions were analyzed as well. The results showed a decreasing trend in the annual average surface humidity from the southeast to the northwest in the research anna. Over the period of 1961-2008, an aridification tendency appeared sharply in the central interior region of the Loess Plateau, and less sharply in the middle part of the region. The border region showed the weakest tendency ol; aridification. It is clear that aridification diffused in all directions from the interior region. The spatial anomaly distribution of the terrestrial surface dry and wet conditions on the Loess Plateau can be divided into three key areas： the southern, western and eastern regions. The terrestrial annual humidity index displayed a significantly descending trend and showed remarkable abrupt changes from wet to dry in the years 1967, 1977 and 1979. In the above mentioned three key areas for dry and wet conditions, the terrestrial annual humidity index exhibited a fluctuation period of 3-4 years, while in the southern region, a fluctuation period of 7-8 years existed at the same time.

关键词： dry and wet conditions spatial distribution temporal variation Penman-Monteith model Loess Plateau

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Remote-sensing data reveals the response of soil erosion intensity to land use change in Loess Plateau, China

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Research in Cold and Arid Regions 2016年第4期8卷 325-333页

作者： JiaLi Xie ChangZhen Yan ZhiXiang Lu Sen Li Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

Developing an effective approach to rapidly assess the effects of restoration projects on soil erosion intensity and theirextensive spatial and temporal dynamics is important for regional ecosystem management and the development of soilconservation strategies in the future. This study applied a model that was developed at the pixel scale using water soilerosion indicators （land use, vegetation coverage and slope） to assess the soil erosion intensity in the Loess Plateau,China. Landsat TM/ETM＋ images in 2000, 2005 and 2010 were used to produce land use maps based on the object-oriented classification method. The MODIS product MOD13Q1 was adopted to derive the vegetation coveragemaps. The slope gradient maps were calculated based on data from the digital elevation model. The area of watersoil-eroded land was classified into six grades by integrating slope gradients, land use and vegetation coverage. Resultsshow that the Grain-To-Green Project in the Loess Plateau worked based on the land use changes from 2000 to 2010and enhanced vegetation restoration and ecological conservation. These projects effectively prevented soil erosion.During this period, lands with moderate, severe, more severe and extremely severe soil erosion intensities significantlydecreased and changed into less severe levels, respectively. Lands with slight and light soil erosion intensities increased.However, the total soil-eroded area in the Loess Plateau was reduced. The contributions of the seven provincesto the total soil-eroded area in the Loess Plateau and the composition of the soil erosion intensity level in eachprovince are different. Lands with severe, more severe and extremely severe soil erosion intensities are mainly distributedin Qinghai, Ningxia, Gansu and Inner Mongolia. These areas, although relatively small, must be prioritised andpreferentially treated.

关键词： remote sensing soil erosion intensity land use Loess Plateau

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Fractions and Bioavailability of Soil Inorganic Phosphorus in the Loess Plateau of China under Different Vegetations

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Acta Geologica Sinica(English Edition) 2011年第1期85卷 263-270页

作者： WEI Xiaorong SHAO Mingan SHAO Hongbo GAO Jianlun XU Gang State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau NorthwestA ＆ F University Yangling 712100 China The CAS/Shandong Provincial Key Laboratory of Coastal Environmental Process Yantai Institute of Costal Zone Research Chinese Academy of Sciences （CAS） Yantai 264003 China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources （CAS ＆ MWR） Yangling 712100 China Institute for Life Sciences Qingdao University of Science ＆ Technology Qingdao 266042 China Mizhi Meteorological Office of Shaanxi Province Mizhi 718100 China

Plants play an important role in soil phosphorus nutrition. However, the effect of plants on phosphorus nutrition in soils of the Loess Plateau of China is not well understood. This study was conducted to reveal the relationships between plants and phosphorus＇ fractions and availability in the Loess Plateau of China. Twenty-two plant communities were surveyed and soil samples under different plant canopies were collected for the determination of soil properties and inorganic phosphorus fractionation. The results showed that Leguminosae and Lilaceae reduced pH and increased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies, while Labiatae and Rosaceae increased pH and decreased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies. The contents of Ca2P, CasP, AI-P and Fe-P were highly related with soil Oisen phosphorus. They were all higher in soils under Leguminosae and Lilaceae and lower in softs under Labiatae and Rosaceae. The results of this study indicate that Leguminosae and Lilaceae improved phosphorus nutrition in soils, yet Labiatae and Rosaceae impeded the improvement of phosphorus nutrition in soils under their canopies, which will be of more help to instruct vegetation restoration in the region and provide information for soil development.

关键词： bioavailability fraction inorganic phosphorus vegetation soil development Loess Plateau

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The impact of land use change on soil organic carbon and labile organic carbon stocks in the Longzhong region of Loess Plateau

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Journal of Arid Land 2012年第3期4卷 241-250页

作者： LiHua ZHANG ZhongKui XIE RuiFeng ZHAO YaJun WANG Gaolan Experiment Station for Ecology and Agriculture Research Cold and Arid Regions Environmental and EngineeringResearch Institute Chinese Academy of Sciences Lanzhou 730000 China College of Geography and Environment Science Northwest Normal University Lanzhou 730070 China

Land use change （LUC） is widely recognized as one of the most important driving forces of global carbon cycles. The soil organic carbon （SOC） and labile organic carbon （LOC） stores were investigated at arable land （AL）, artificial grassland （AG）, artificial woodland （AW）, abandoned arable land （AAL） and desert steppe （DS） in the Longzhong region of the Loess Plateau in Northwest China. The results showed that conversions from DS to AL, AL to AG and AL to AAL led to an increase in SOC content, while the conversion from DS to AW led to a decline. The differences in SOC content were significant between DS and AW at the 20-40 cm depth and between AL and AG at the 0-10 cm depth. The SOC stock in DS at the 0-100 cm depth was 39.4 t/hm2, increased by 28.48% after cultivation and decreased by 19.12% after conversion to AW. The SOC stocks increased by 2.11% from AL to AG and 5.10% from AL to AAL. The LOC stocks changed by a larger magnitude than the SOC stocks, which suggests that it is a more sensitive index of carbon dynamics under a short-term LUC. The LOC stocks increased at 0-20 cm and 0-100 cm depths from DS to AW, which is opposite to that observed for SOC. The proportion of LOC to SOC ranged from 0.14 to 0.20 at the 0-20 cm depth for all the five land use types, indicating low SOC dynamics. The allocation proportion of LOC increased for four types of LUC conversion, and the change in magnitude was largest for DS to AW （40.91%）. The afforestation, abandonment and forage planting on arable land led to sequestration of SOC; the carbon was lost initially after afforestation. However, the carbon sink effect after abandonment may not be sustainable in the study area.

关键词： carbon sequestration labile organic carbon land use cultivation abandonment Loess Plateau

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Positive and negative terrains on northern Shaanxi Loess Plateau

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Journal of Geographical Sciences 2010年第1期20卷 64-76页

作者： ZHOU Yi TANG Guo＇an YANG Xin XIAO Chenchao ZHANG Yuan LUO Mingliang Key Laboratory of Virtual Geographic Environment of Ministry of Education Nanjing Normal University Nanjing 210046 China Institute of RS and GIS Peking University Beijing 100871 China School of Foreign Languages Central South University Changsha 410083 China College of Land and Resources China West Normal University Nanchong 637002 Sichuan China

The loess positive and negative terrains （P-N terrains）, which are widely distributed on the Loess Plateau, are discussed for the first time by introducing its characteristic, demarcation as well as extraction method from high-resolution Digital Elevation Models. Using 5 m-resolution DEMs as original test data, P-N terrains of 48 geomorphological units in different parts of Shaanxi Loess Plateau are extracted accurately. Then six indicators for depicting the geomorphologic landscape and spatial configuration characteristic of P-N terrains are proposed. The spatial distribution rules of these indicators and the relationship between the P-N terrains and loess relief are discussed for further understanding of loess landforms. Finally, with the integration of P-N terrains and traditional terrain indices, a series of un-supervised classification methods are applied to make a proper landform classification in northern Shaanxi. Results show that P-N terrains are an effect clue to reveal energy and substance distribution rules on the Loess Plateau. A continuous change of P-N terrains from south to north in Shaanxi Loess Plateau shows an obvious spatial difference of loess land-forms and the positive terrain area only accounted for 60.5% in this region. The P-N terrains participant landform classification method increases validity of the result, especially in the loess tableland, loess tableland-ridge and the loess low-hill area. This research is significant on the study of loess landforms with the Digital Terrains Analysis methods.

关键词： Loess Plateau positive and negative terrains DEM shoulder-lines spatial differentiation

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Multitemporal UAV-based photogrammetry for landslide detection and monitoring in a large area:a case study in the Heifangtai terrace in the Loess Plateau of China

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Journal of Mountain Science 2020年第8期17卷 1826-1839页

作者： XU Qiang LI Wei-le JU Yuan-zhen DONG Xiu-jun PENG Da-lei State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China

With high spatial resolution,on-demand-flying ability,and the capacity for obtaining threedimensional measurements,unmanned aerial vehicle(UAV)photogrammetry is widely used for detailed investigations of single landslides,but its effectiveness for landslide detection and monitoring in a large area needs to be investigated.The Heifangtai terrace in the Loess Plateau of China is a loess terrace that is extremely susceptible to irrigation-induced loess landslides.This paper used UAV-based photogrammetry for a series of highresolution images spanning over 30 months for landslide detection and monitoring of the terrace with an area of 32 km^2.Dense and evenly distributed ground control points were established and measured to ensure the high accuracy of the photogrammetry results.The structure-from-motion(Sf M)technique was used to convert overlapping images into orthographic images,3D point clouds,digital surface models(DSMs)and mesh models.Using multitemporal differential mesh models,landslide vertical movements and potential landslides were detected and monitored.The results indicate that a combination of UAV-based orthophotos and differential mesh models can be used for flexible and accurate detection and monitoring of potential loess landslides in a large area.

关键词： Unmanned Aerial Vehicle Loess Plateau Landslide detection Landslide monitoring Differential mesh model Vertical movement

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Modified vegetation-erosion dynamics model and its application in typical watersheds in the Loess Plateau

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International Journal of Sediment Research 2011年第1期26卷 78-86页

作者： CHEN Yuehong~1,WANG Feixin~2,LIU Guangquan~3,YU Xinxiao~4, JIA Guodong~5,and GAN Ping~6 China Institute of Water Resources and Hydropower Research,Beijing 100048 International Research and Training Center on Erosion and Sediment Research,Beijing 100048,China Beijing Forestry University,Beijing 100083,China. Key Lab of Dredging Technology of CCGRP,Shanghai Waterway Engineering Design and Consulting Co., Ltd,Shanghai 200120,China. International Research and Training Center on Erosion and Sedimentation China Institute of Water Resources and Hydropower Research,Beijing 100048 Northwest A&F University,Yangling 712100,China, Beijing Forestry University,Beijing 100083,China, Beijing Forestry University,Beijing 100083,China. China Institute of Water Resources and Hydropower Research,Beijing 100048,and International Research and Training Center on Erosion and Sediment Research,Beijing 100048,China Assoc. Prof. Dr. China Institute of Water Resources and Hydropower Research Beijing 100048 International Research and Training Center on Erosion and Sediment Research Beijing 100048 China Beijing Forestry University Beijing 100083 China Dr. Key Lab of Dredging Technology of CCGRP Shanghai Waterway Engineering Design and Consulting Co. Ltd Shanghai 200120 China Prof. Dr. International Research and Training Center on Erosion and Sedimentation China Institute of Water Resources and Hydropower Research Beijing 100048 Northwest A&F University Yangling 712100 China Prof. Dr. Beijing Forestry University Beijing 100083 China Dr. Beijing Forestry University Beijing 100083 China Engineer China Institute of Water Resources and Hydropower Research Beijing 100048 and International Research and Training Center on Erosion and Sediment Research Beijing 100048 China

The vegetation-erosion model was applied in three typical watersheds of hilly and gully area in the Loess Plateau in northwestern China to study the dynamic relations between vegetation coverage and soil erosion rate and various stresses.The model was improved by introducing rainfall and runoff factors.Then the modified model was applied in the Luergou and Luoyugou watersheds.The calculation results with the modified model were compared with the results of the original model.The precisions of simulated vegetation coverage and soil erosion rate with the modified model were greatly improved compared with the original model.Soil erosion rate reduced with increasing vegetation coverage and the human disturbance caused high soil erosion.

关键词： Soil erosion Vegetation coverage Vegetation-erosion dynamics model Loess Plateau Modified model

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Effects of landuse change on surface runoff and sediment yield at different watershed scales on the Loess Plateau

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International Journal of Sediment Research 2010年第3期25卷 283-293页

作者： ZHANG Xiaoming1, CAO Wenhong2, GUO Qingchao3, and WU Sihong41 Assoc. Prof. Dr., China Institute of Water Resources and Hydropower Research, Beijing 100048, China, 2,3 Prof. Dr., China Institute of Water Resources and Hydropower Research, Beijing 100048, China, 4 Dr., Department of Land and Water Resources Engineering, Royal Institute of Technology, Stockholm, SE-100 44, Sweden Assoc. Prof. Dr. China Institute of Water Resources and Hydropower Research Beijing 100048 China Prof. Dr. China Institute of Water Resources and Hydropower Research Beijing 100048 China Dr. Department of Land and Water Resources Engineering Royal Institute of Technology Stockholm SE-100 44 Sweden

Erosion and sediment yield from large and small watersheds exhibit different laws. Variations in surface runoff and sediment yield because of landuse change in four watersheds of different scales from 1 km2 to 73 km2 were analyzed. Due to reforestation and farmland terracing, surface runoff and sediment yield reduced by 20-100% and 10-100% respectively. Reductions in surface runoff were differed significantly under different precipitation regimes. For the large watershed (73 km2) landuse change had similar effects on surface runoff regardless of changing of precipitation. For the small watershed (1 km2) landuse change had fewer effects on surface runoff under high precipitation. The relative changes of sediment yield in the four watersheds under reforestation and farmland terracing decreased as precipitation increased from 350 mm to 650 mm, then increased as precipitation increased from 650 mm to 870 mm. Where initial forest coverage rate was below 45%, sediment yield decreased dramatically as forest coverage rate increased. Watershed management with aiming at reducing both surface runoff and sediment yield should be conducted both on sloping surfaces and in channels in large watersheds.

关键词： Soil erosion Land use change Scale effect Surface runoff and sediment yield Watershed Loess Plateau

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