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Patterns of Soil ^(15)N and Total N and Their Relationships with Environmental Factors on the Qinghai-Tibetan Plateau

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Pedosphere 2014年第2期24卷 232-242页

作者： ZHOU Lei SONG Ming-Hua WANG Shao-Qiang FAN Jiang-Wen LIU Ji-Yuan ZHONG Hua-Ping YU Gui-Rui GAO Lu-Peng HU Zhong-Min CHEN Bin WU Wei-Xing SONG Ting key laboratory of ecosystem network observation and Modelling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences University of Chinese Academy of Sciences

The patterns of soil nitrogen （N） isotope composition at large spatial and temporal scales and their relationships to environmental factors illustrate N cycle and sources of N, and are integrative indicators of the terrestrial N cycle and its response to global change. The objectives of this study were： i） to investigate the patterns of soil N content and natural abundance of 15N （δ15N） values in different ecosystem types and soil profiles on the Qinghai-Tibetan Plateau; ii） to examine the effects of climatic factors and soil characteristics on the patterns of soil N content and soil δ15N values; and iii） to test the relationship between soil δ15N values and soil C/N ratios across ecosystems and soil profiles. Soil profiles were sampled at 51 sites along two transects 1 875 km in length and 200 km apart and distributed in forest, meadow and steppe on the Qinghai-Tibetan Plateau. Each site was sampled every 10 cm from a soil depth of 0 to 40 cm and each sample was analyzed for soil N content and δ15N values. Our results indicated that soil N and 515N values （0-40 cm） in meadows were much higher than in desert steppe. Soil N decreased with soil depth for each ecosystem, while variations of soil ~15N values along soil profiles were not statistically significant among most ecosystems but for mountain meadow, lowland meadow, and temperate steppe where soil δ15N values tended to increase with soil depth. The parabolic relationship between soil δ15N values and mean annual precipitation indicated that soil δ15N values increased with increasing precipitation in desert steppe up to 500 mm, and then decreased with increasing precipitation across all other ecosystems. Moreover, the parabolic relationship between δ15N values and mean annual temperature existed in all individual ecosystem types. Soil N and δ15N values （0-0 cm） increased with an increase in soil silt and clay contents. Furthermore, a threshold of C/N ratio of about 11 divided the parabolic relationship between soi

关键词： desert steppe nitrogen isotope composition nutrient availability soil nitrogen

Response of plant physiological parameters to soil water availability during prolonged drought is affected by soil texture

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Journal of Arid Land 2021年第7期13卷 688-698页

作者： HUANG Laiming ZHAO Wen SHAO Ming'an key laboratory of ecosystem network observation and modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Soil water deficit is increasingly threatening the sustainable vegetation restoration and ecological construction on the Loess Plateau of China due to the climate warming and human *** determine the response thresholds of Amygdalus pedunculata(AP)and Salix psammophila(SP)to soil water availability under different textural soils,we measured the changes in net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),leaf water potential(ψw),water use efficiency(WUE)and daily transpiration rate(Td)of the two plant species during soil water content(SWC)decreased from 100%field capacity(FC)to 20%FC in the sandy and loamy soils on the Loess Plateau in the growing season from June to August in *** showed that Pn,Gs,WUE and Td of AP and SP remained relatively constant at the beginning of soil water deficit but decreased rapidly as plant available soil water content(PASWC)fell below the threshold values in both the sandy and loamy *** PASWC thresholds corresponding to Pn,Gs and Ci of AP in the loamy soil(0.61,0.62 and 0.70,respectively)were lower than those in the sandy soil(0.70,0.63 and 0.75,respectively),whereas the PASWC thresholds corresponding to Pn,Gs and Ci of SP in the loamy soil(0.63,0.68 and 0.78,respectively)were higher than those in the sandy soil(0.58,0.62 and 0.66,respectively).In addition,the PASWC thresholds in relation to Td and WUE of AP(0.60 and 0.58,respectively)and SP(0.62 and 0.60,respectively)in the loamy soil were higher than the corresponding PASWC thresholds of AP(0.58 and 0.52,respectively)and SP(0.55 and 0.56,respectively)in the sandy ***,the PASWC thresholds for the instantaneous gas exchange parameters(e.g.,Pn and Gs)at the transient scale were higher than the thresholds for the parameters(e.g.,Td)at the daily *** study demonstrates that different plant species and/or different physiological parameters exhibit different thresholds of PASWC and that the thresholds are affect

关键词： plant available soil water content drought stress soil water deficit sustainable vegetation restoration sandy soil loamy soil Loess Plateau

Five-year warming does not change soil organic carbon stock but alters its chemical composition in an alpine peatland

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Pedosphere 2023年第5期33卷 776-787页

作者： Jingcong QIU Minghua SONG Chunmei WANG Xiaomin DOU Fangfang LIU Jiaxin WANG Chenying ZHU Shiqi WANG College of Environmental Science and Engineering Beijing Forestry UniversityBeijing 100083China key laboratory of ecosystem network observation and modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Climate warming may promote soil organic carbon(SOC)decomposition and alter SOC stocks in terrestrial ecosystems,which would in turn affect climate *** manipulated a warming experiment using open-top chambers to investigate the effect of warming on SOC stock and chemical composition in an alpine peatland in Zoigêon the eastern Tibetan Plateau,*** showed that 5 years of warming soil temperatures enhanced ecosystem respiration during the growing season,promoted above-and belowground plant biomass,but did not alter the SOC ***,labile O-alkyl C and relatively recalcitrant aromatic C contents decreased,and alkyl C content *** also increased the amount of SOC stored in the silt-clay fraction(0.25 mm,respectively).These changes in labile and recalcitrant C were largely associated with warming-induced increases in soil microbial biomass C,fungal diversity,enzyme activity,and functional gene abundance related to the decomposition of labile and recalcitrant C *** warming-induced accumulation of SOC stored in the silt-clay fraction could increase SOC persistence in alpine peatland *** findings suggest that mechanisms mediated by soil microbes account for the changes in SOC chemical composition and SOC in different aggregate size fractions,which is of great significance when evaluating SOC stability under climate warming conditions.

关键词： functional gene nuclear magnetic resonance simulated global warming soil carbon components soil enzymes soil microbial diversity

Spatial pattern of grassland aboveground biomass and its environmental controls in the Eurasian steppe

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Journal of Geographical Sciences 2017年第1期27卷 3-22页

作者： JIAO Cuicui YU Guirui HE Nianpeng MA Anna GE Jianping HU Zhongmin Synthesis Research Center of Chinese ecosystem Research network Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China College of Life Sciences Beijing Normal UniversityBeijing 100875China

Vegetation biomass is an important component of terrestrial ecosystem carbon stocks. Grasslands are one of the most widespread biomes worldwideplaying an important role in global carbon cycling. Thereforestudying spatial patterns of biomass and their correlations to environment in grasslands is fundamental to quantifying terrestrial carbon budgets. The Eurasian steppean important part of global grasslandsis the largest and relatively well preserved grassland in the world. In this studywe analyzed the spatial pattern of aboveground biomass（AGB）and correlations of AGB to its environment in the Eurasian steppe by meta-analysis. AGB data used in this study were derived from the harvesting method and were obtained from three data sources（literatureglobal NPP database at the Oak Ridge National laboratory Distributed Active Archive Center（ORNL）some data provided by other researchers）. Our results demonstrated that：（1） as for the Eurasian steppe overallthe spatial variation in AGB exhibited significant horizontal and vertical zonality. In detailAGB showed an inverted parabola curve with the latitude and with the elevationwhile a parabola curve with the longitude. In additionthe spatial pattern of AGB had marked horizontal zonality in the Black Sea-Kazakhstan steppe subregion and the Mongolian Plateau steppe subregionwhile horizontal and vertical zonality in the Tibetan Plateau alpine steppe subregion.（2） Of the examined environmental variablesthe spatial variation of AGB was related to mean annual precipitation（MAP）mean annual temperature（MAT）mean annual solar radiation（MAR）soil Gravel contentsoil p H and soil organic content（SOC） at the depth of 0–30 cm. NeverthelessMAP dominated spatial patterns of AGB in the Eurasian steppe and its three subregions.（3） A Gaussian function was found between AGB and MAP in the Eurasian steppe overallwhich was primarily determined by unique patterns of grasslands and environment in the Tibetan Plateau. AGB was significantly positively relat

关键词： the Eurasian steppe aboveground biomass spatial pattern parabola curve Gaussian function

A Brief Introduction to Chinese ecosystem Research network(CERN)

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Journal of Resources and Ecology 2015年第3期6卷 192-196页

作者： LI Shenggong YU Guirui YU Xiubo HE Honglin GUO Xuebing Synthesis Center for Chinese ecosystem Research network CAS key laboratory of ecosystem network observation and modeling CAS Institute of Geographic Sciences and Natural Resources Research CAS

An ecosystem communities with is one or many a variety of biotic （living organisms including plants, animals and microbes） and abiotic （things like air, water and mineral soil） components that function in an interrelated fashion （Chapin et al. 2012）. These biotic and abiotic components linked together through nutrient cycles and energy flows （Chapin et al. 2012）. ecosystems provide humanity with a wide range of services, which are vital to sustaining human health and well-being, and social and economic development （MEA 2005）. These services are categorized into provisioning, regulating,

关键词：中国生态系统研究网络 CERN 经济社会发展人类健康非生物生态社区功能部件生物成分

Identification of sand and dust storm source areas in Iran

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Journal of Arid Land 2015年第5期7卷 567-578页

作者： CAO Hui LIU Jian WANG Guizhou YANG Guang LUO Lei key laboratory of ecosystem network observation and modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences International ecosystem Management Partnership United Nations Environment Programme University of Chinese Academy of Sciences Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences

Sand and dust storms （SDS） are common phenomena in arid and semi-arid areas. In recent years, SDS frequencies and intensities have increased significantly in Iran. A research on SDS sources is important for understanding the mechanisms of dust generation and assessing its socio-economic and environmental impacts. In this paper, we developed a new approach to identify SDS source areas in Iran using a combination of nine related datasets, namely drought events, temperature, precipitation, location of sandy soils, SDS frequency, hu- man-induced soil degradation （HISD）, human influence index （HII）, rain use efficiency （RUE） and net primary pro- ductivity （NPP） loss. To identify SDS source areas, we firstly normalized these datasets under uniform criteria in- cluding layer reprojection using Lambert conformal conic projection, data conversion from shapefile to raster, Min-Max Normalization with data range from 0 to 1, and data interpolation by Kriging and images resampling （resolution of 1 km）. After that, a score map for the possibility of SDS sources was generated through overlaying multiple datasets under average weight allocation criterion, in which each item obtained weight equally. In the score map, the higher the score, the more possible a specific area could be regarded as SDS source area. Exceptions mostly came from large cities, like Tehran and Isfahan. As a result, final SDS source areas were mapped out, and Al-Howizeh/Al-Azim marshes and Sistan Basin were identified as main SDS source areas in Iran. The SDS source area in Al-Howizeh/Al-Azim marshes still keeps expanding. In addition, Al-Howizeh/Al-Azim marshes are now suf- fering rapid land degradation due to natural and human-induced factors and might totally vanish in the near future. Sistan Basin also demonstrates the impacts of soil degradation and wind erosion. With appropriate intensity, dura- tion, wind speed and altitude of the dust storms, sand particles uplifting from this area might have developed

关键词： sand and dust storm weight allocation criterion Kriging interpolation score map AI-Howizeh/AI-Azim marshes Sistan Basin

Assessing spatio-temporal variations of precipitation-use efficiency over Tibetan grasslands using MODIS and in-situ observations

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Frontiers of Earth Science 2016年第4期10卷 784-793页

作者： Zhengjia LIU Mei HUANG key laboratory of ecosystem network observation and modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China State key laboratory of Remote Sensing Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Beijing 100101 China

Clarifying the spatial and temporal variations in precipitation-use efficiency （PUE） is helpful for advancing our knowledge of carbon and water cycles in Tibetan grassland ecosystems. Here we use an integrated remote sensing normalized difference vegetation index （NDVI） and in-situ above-ground net primary production （ANPP） measurements to establish an empirical exponen- tial model to estimate spatial ANPP across the entire Tibetan Plateau. The spatial and temporal variations in PUE （the ratio of ANPP to mean annual precipitation （MAP））, as well as the relationships between PUE and other controls, were then investigated during the 2001- 2012 study period. At a regional scale, PUE increased from west to east. PUE anomalies increased significantly （〉 0.1 g.m^-***^-1/10 yr） in the southern areas of the Tibetan Plateau yet decreased （〉 0.02 g. m^-2. mm 1/10 yr） in the northeastern areas. For alpine meadow, we obtained an obvious breaking point in trend of PUE against elevation gradients at 3600 m above the sea level, which showed a contrasting relationship. At the inter-annual scale, PUE anomalies were smaller in alpine steppe than in alpine meadow. The results show that PUE of Tibetan grasslands is generally high in dry years and low in wet years.

关键词： normalized difference vegetation index(NDVI) Tibetan Plateau inter-annual variations alpinegrasslands exponential model

Revegetation with artificial plants improves topsoil hydrological properties but intensifies deep-soil drying in northern Loess Plateau,China

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Journal of Arid Land 2018年第3期10卷 335-346页

作者： ZHANG Qingyin JIA Xiaoxu ZHAO Chunlei SHAO Ming'an State key laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University key laboratory of ecosystem network observation and modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences

Knowledge about the effects of vegetation types on soil properties and on water dynamics in the soil profile is critical for revegetation strategies in water-scarce regions, especially the choice of vegetation type and human management measures. We focused on the analysis of the effects of vegetation type on soil hydrological properties and soil moisture variation in the 0–400 cm soil layer based on a long-term（2004―2016） experimental data in the northern Loess Plateau region, China. Soil bulk density（BD）, saturated soil hydraulic conductivity（Ks）, field capacity（FC） and soil organic carbon（SOC） in 2016, as well as the volumetric soil moisture content during 2004–2016, were measured in four vegetation types, i.e., shrubland（korshinsk peashrub）, artificial grassland（alfalfa）, fallow land and cropland（millet or potato）. Compared with cropland, revegetation with peashrub and alfalfa significantly decreased BD and increased Ks, FC, and SOC in the 0–40 cm soil layer, and fallow land significantly increased FC and SOC in the 0–10 cm soil layer. Soil water storage（SWS） significantly declined in shrubland and grassland in the 40–400 cm soil layer, causing severe soil drought in the deep soil layers. The study suggested that converting cropland to grassland（alfalfa） and shrubland（peashrub） improved soil-hydrological properties, but worsened water conditions in the deep soil profile. However, natural restoration did not intensify deep-soil drying. The results imply that natural restoration could be better than revegetation with peashrub and alfalfa in terms of good soil hydrological processes in the semi-arid Loess Plateau region.

关键词： soil drying soil hydrological property soil moisture vegetation restoration Loess Plateau

Effects of climate and forest age on the ecosystem carbon exchange of afforestation

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Journal of Forestry Research 2020年第2期31卷 365-374页

作者： Zhi Chen Guirui Yu Qiufeng Wang Synthesis Research Center of Chinese ecosystem Research network and Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101People’s Republic of China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049People’s Republic of China

Afforestation is believed to be an effective practice to reduce global warming by sequestering large amounts of carbon in plant biomass and ***,the factors that determine the rate of carbon sequestration with afforestation are still poorly *** analyzed ecosystem carbon exchange after afforestation based on eddy covariance measurements with the aim to identify factors responsible for the rate of carbon exchange following *** results indicated that afforestation in the tropical/subtropical and temperate climate zones had greater capacities for carbon sequestration than those in boreal *** ecosystem production(NEP),gross primary production(GPP)and ecosystem respiration(RE)varied greatly with age groups over ***,NEP was initially less than zero in the\10 year group and then increased to its peak in the 10-20 year *** of varied previous land use types and planting of diverse tree species did not result in different carbon *** general linear model showed that climate zone and age of afforestation were the dominant factors influencing carbon *** factors jointly controlled 51%,61%and 63%of the variation in NEP,GPP and RE,*** to the strong regulation of climate on GPP and RE,NEP showed greater sensitivity to the age of *** results increase our understanding of the variation in ecosystem carbon exchange of afforestation and suggest that afforestation in subtropical and temperate areas after 20 years would yield greater carbon sink benefits than would afforestation of boreal regions.

关键词： Afforestation Carbon sequestration Eddy covariance Climate Age