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Root characteristics of Alhagi sparsifolia seedlings in response to water supplement in an arid region,northwestern China

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Journal of Arid Land 2013年第4期5卷 542-551页

作者： DongWei GUI FanJiang ZENG Zhen LIU Bo ZHANG State Key Laboratory of Desert and oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences Cele national station of observation & research for Desert-Grassland ecosystem in Xinjiang Key Laboratory of Biogeography and Bioresource in Arid Land Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences

The effect of variation in water supply on woody seedling growth in arid environments remain poorly *** subshrub Alhagi sparsifolia Shap.（Leguminosae）,distributed in the southern fringe of the Taklimakan Desert,Xinjiang,northwestern China,has evolved deep roots and is exclusively dependent on groundwater,and performs a crucial role for the local ecological *** the Cele oasis,we studied the responses of *** seedling roots to water supplement at 10 and 14 weeks under three irrigation treatments （none water supply of 0 m3/m2 （NW）,middle water supply of 0.1 m3/m2 （MW）,and high water supply of 0.2 m3/m2 （HW））.The results showed that the variations of soil water content （SWC） significantly influenced the root growth of *** *** leaf area,basal diameter and crown diameter were significantly higher in the HW treatment than in the other *** biomass,root surface area （RSA）,root depth and relative growth rate （RGR） of *** roots were all significantly higher in the NW treatment than in the HW and MW treatments at 10 ***,these root parameters were significantly lower in the NW treatment than in the other treatments at 14 *** SWC continued to decline as the experiment went on （until less than 8％ gravimetric SWC）,the seedlings still showed drought tolerance through morphological and physiological responses,but root growth suffered serious water stress compared to better water supply *** to our study,keeping a minimum gravimetric SWC of 8％ might be important for the growth and establishment of *** during the early growth *** results will not only enrich our knowledge of the responses of woody seedlings to various water availabilities,but also provide a new insight to successfully establish and manage *** in arid environments,further supporting the sustainable development of oases.

关键词： arid environment Alhagi sparsifolia roots irrigation treatments oasis

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Abiotic contribution to total soil CO_2 flux across a broad range of land-cover types in a desert region

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Journal of Arid Land 2017年第1期9卷 13-26页

作者： MA Jie LIU Ran LI Yan State Key Laboratory of Desert and oasis Ecology Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Fukang national Field Scientific observation and research station for Desert ecosystems Chinese Academy of Sciences

As an important component of ecosystem carbon（C） budgets, soil carbon dioxide（CO2） flux is determined by a combination of a series of biotic and abiotic processes. Although there is evidence showing that the abiotic component can be important in total soil CO2 flux（R（total））, its relative importance has never been systematically assessed. In this study, after comparative measurements of CO2 fluxes on sterilized and natural soils, the R（total） was partitioned into biotic flux（R（biotic）） and abiotic flux（R（abiotic）） across a broad range of land-cover types（including eight sampling sites： cotton field, hops field, halophyte garden, alkaline land, reservoir edge, native saline desert, dune crest and interdune lowland） in Gurbantunggut Desert, Xinjiang, China. The relative contribution of R（abiotic） to R（total）, as well as the temperature dependency and predominant factors for R（total）, R（biotic） and R（abiotic）, were analyzed. Results showed that R（abiotic） always contributed to R（total） for all of the eight sampling sites, but the degree or magnitude of contribution varied greatly. Specifically, the ratio of R（abiotic） to R（total） was very low in cotton field and hops field and very high in alkaline land and dune crest. Statistically, the ratio of R（abiotic） to R（total） logarithmically increased with decreasing R（biotic）, suggesting that R（abiotic） strongly affected R（total） when R（biotic） was low. This pattern confirms that soil CO2 flux is predominated by biotic processes in most soils, but abiotic processes can also be dominant when biotic processes are weak. On a diurnal basis, R（abiotic） cannot result in net gain or net loss of CO2, but its effect on transient CO2 flux was significant. Temperature dependency of R（total） varied among the eight sampling sites and was determined by the predominant processes（abiotic or biotic） of CO2 flux. Specifically, R（biotic） was driven by soil temperature while R（abiotic） was regulated by the change in soil temperature（ΔT）. Namely

关键词： soil CO2 flux biotic flux abiotic flux temperature dependence Gurbantunggut Desert

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The continuing shrinkage of snow cover in High Mountain Asia over the last four decades

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Science Bulletin 2022年第20期67卷 2064-2068,M0003,M0004页

作者： Yupeng Li Fan Sun Yaning Chen Baofu Li Gonghuan Fang Weili Duan Qianqian Xia State Key Laboratory of Desert and oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 10049China akesu national station of observation and research for oasis agro-ecosystem Akesu 843017China School of Geography and Tourism Qufu Normal UniversityRizhao 276826China College of Geography and Remote Sensing Sciences Xinjiang UniversityUrumqi 830046China College of Biology and Geography Yili Normal UniversityYining 835000China

High Mountain Asia (HMA), known as Earth's "Third Pole" and"Asia's water tower",. is the largest glacier and snow reservoir onEarth except for the polar ice sheets (Text S1 and Fig. S1 online)。Snow is an important component of the HMA cryosphere, and itsvariability directly affects the water and energy balances in theregion [1,2] The average warming rate in the HMA region in recentdecades is approximately twofold higher than the average warm-ing rate in China and the world in the same period. The climatologyand trends of snow cover in the HMA have been investigated basedon station and satellite observations. However, these methodshave some limitations, resulting in large uncertainties or limita-tions in assessing long-term snow cover changes in the *** changes in the HMA region analyzed over a short timeseries may also lead to conclusions that are inconsistent with con-ventional assertions. Several studies of the temporal and spatialvariability of snow cover in the HMA region using short-termModerate Resolution lmaging Spectroradiometer data revealed nosignificant shrinkage in the snow cover area (SCA) [3].

关键词：随机森林青藏高原东南部结束日期敏感性分析 SCP 雪盖 SCD

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Characteristics of Wind Erosion and Deposition in oasis-desert Ecotone in Southern Margin of Tarim Basin,China

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Chinese Geographical Science 2014年第6期24卷 658-673页

作者： MAO Donglei LEI Jiaqiang ZENG Fanjiang RAHMUTULLA Zaynulla WANG Cui ZHOU Jie Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences University of Chinese Academy of Sciences College of Geographical Science and Tourism Xinjiang Normal University Cele national station of observation and research for Desert-Grassland ecosystem in Xinjiang

The oasis-desert ecotone is a fragile ecological zone that is affected both by oasis and desert conditions. To understand the impact of the differences in wind power, and the influence of wind erosion and deposition on the ecotone, meteorological data and con- temporaneous wind erosion and deposition data were collected on the southern margin of Tarim Basin with serious sand-blown hazards. The wind velocity, average wind velocity, sand drift potential （DP）, resultant sand drift potential （RDP）, and sand transportation rate decrease significantly and successively across four landscape types with increasing vegetation coverage （VC）. Flat surfaces and areas of shifting sandy ground experience intense wind erosion with fast movement of mobile sand dunes; semi-fixed sand areas experience ex- tensive wind deposition but only slight wind erosion; and fixed sand areas experience only slight wind erosion and deposition. Volume of wind erosion on bare newly reclaimed farmland is up to 6.96 times that of bare shifting sandy ground. Wind erosion volume per unit area and VC follow an exponential function relationship in natural conditions, while wind deposition volume per unit area does not conform to any functions which has close relationship with vary topography and arrangement patterns of vegetation besides for VC. The results indicate that the volume of wind erosion has a close correlation with VC, and different types and distribution patterns of topog- raphy and vegetation also profoundly influence the wind deposition volume in the field, and underground water tables in different land- scape types control the plant community distribution. Keywords： wind erosion; wind deposition; oasis-desert ecotone; vegetation coverage （VC）; topography; Cele County

关键词： wind erosion wind deposition oasis-desert ecotone vegetation coverage (VC) topography Cele County

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Re-evaluating the vertical mass-flux profiles of aeolian sediment at the southern fringe of the Taklimakan Desert, China

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Journal of Arid Land 2015年第6期7卷 765-777页

作者： XUE Jie LEI Jiaqiang LI Shengyu GUI Dongwei MAO Donglei ZHOU Jie State Key Laboratory of Desert and oasis Ecology Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Cele national station of observation and research for Desert-Grassland ecosystem Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences Key Laboratory of Biogeography and Bioresource in Arid Land Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences University of Chinese Academy of Sciences

Reliable estimation of the mass-flux profiles of aeolian sediment is essential for predicting sediment transport rates accurately and designing measures to cope with wind-erosion. Vertical mass-flux profiles from seventeen wind-erosion events were re-evaluated using five typical models based on observed data obtained from a smooth bare field at the southern fringe of the Taklimakan Desert, China. The results showed that the exponential-function model and the logarithmic-function model exhibited the poorest fit between observed and predicted mass-flux profiles. The power-function model and the modified power-function model improved the fit to field data to an equivalent extent, while the five-parameter combined-function model with a scale constant（σ） of 0.00001 m（different from the σ value proposed by Fryear, which represented the height above which 50% of the total mass flux occurred） was verified as the best for describing the vertical aeolian sediment mass-flux profiles using goodness of fit（R2） and the Akaike Information Criterion（AIC） values to evaluate model performance. According to relationships among model parameters, the modified power model played a prominent explanatory role in describing the vertical profiles of the observed data, whereas the exponential model played a coordinating role. In addition, it was found that the vertical profiles could not be extrapolated using the five selected models or easily estimated using an efficient model without field observations by a near-surface sampler at 0 to 0.05 m.

关键词： vertical profile mass flux aeolian sediment wind erosion Taklimakan Desert

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Magnetic mineral diagenesis in sediments of saline lake Lop Nur

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Journal of Mountain Science 2019年第3期16卷 548-560页

作者： LI Wen MU Gui-jin LIN Yong-chong SONG Hao-ze State Key Laboratory of Desert and oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences Cele national station of observation and research for Desert-Grassland ecosystems University of Chinese Academy of Sciences School of history and Geography Minnan Normal University

Saline lakes are useful repositories for paleo-climatic records. In recent years, magnetic properties of saline lake sediments have been widely applied to establish paleo-climatic change. However,the influence factors of magnetic properties in saline lakes have not been fully understood, which complicates the paleoenvironmental ***, we present a rock magnetic analyses result of LOP_1 profile(40°26′09″′N, 90°21′23″E) from Lop Nur, a well-known saline lake, located in the eastern Tarim Basin in northwestern China. We combined the particle size, total organic content, and mineral characteristics analysis to assess the influence factors of magnetic properties in Lop Nur and its environmental significance. The results indicate that early diagenesis is the major influence factor on magnetic properties of Lop Nur saline *** greigite and pyrite are identified within organic-rich sediments, which produce zones with high and low magnetic susceptibilities, *** different authigenic iron sulfide contents in different layers are related to sedimentary environment changes. Sufficient supplies of organic matter and sulphate and low sedimentation rates favour the pyritization process. Moreover, if pyritization was constrained, intermediate greigite formed and was preserved. In oxidizing environments, sediment magnetic properties are consistent with those of source materials from Tarim Basin and are mainly controlled by particle size and hydrodynamic sorting of mainly detrital magnetite is largely unaffected by early diagenesis. Our study demonstrates that magnetic properties can provide a robust approach for studying depositional environment change in saline lake. In addition, the information obtained in this study would also provide insights into the geochemical processes of iron element in saline lakes.

关键词： Early diagenesis Magnetic properties Saline lake Lop Nur

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Characteristics of Meteorological Factors over Different Landscape Types During Dust Storm Events in Cele,Xinjiang,China

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Journal of Meteorological research 2014年第4期28卷 576-591页

作者：毛东雷雷加强李生宇曾凡江王翠周杰 Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences University of Chinese Academy of Sciences College of Geographical Sciences and Tourism Xinjiang Normal University Cele national station of observation and research for Desert-Grassland ecosystem in Xinjiang

Landscape characteristics influence meteorological factors, thus affect the occurrence and nature of dust storm events. The present study investigates the spatiotemporal characteristics of six meteorological factors （wind velocity, wind direction, air temperature, relative humidity （RH）, photo synthetically active radiation （PAR）, and solar radiation） over different landscape types （shifting-sand frontier, semi-fixed sandy land, fixed sandy land, and the inner region of an oasis） before and after dust storms during four typical dust storm events in an oasis-desert ecotone in Cele, Xinjiang, China. The results show that the average wind velocity decreased significantly from the shifting-sand frontier to the inner oasis, which was mainly attributable to the vegetation coverage. Before the dust storm events, there were obvious differences in air temperature and RH either in the horizontal or vertical direction over the different landscape types. However, these factors were very similar during and following the dust storm events. PAR and solar radiation were significantly reduced during the dust storm events and the subsequent sand-blowing and floating-dust conditions. This effect was much stronger than during similar weather conditions without dust storm events such as sand-blowing and overcast and/or rainy days. Additionally, the variation in the meteorological factors among the different landscapes was also affected by the prevailing wind direction during the dust storm events. However, the landscape type slightly changed the prevailing wind direction, with the greatest dispersion distribution of wind direction in the inner oasis. The findings of this study are helpful for understanding the function of landscape types in the occurrence of dust storms, as well as for providing a theoretical basis for prevention of dust storms.

关键词： dust storms weather meteorological factors changing characteristics Cele

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Optimal root system strategies for desert phreatophytic seedlings in the search for groundwater

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Journal of Arid Land 2015年第4期7卷 462-474页

作者： LI Changjun ZENG Fanjiang ZHANG Bo LIU Bo GUO Zichun GAO Huanhuan TIYIP Tashpolat State Key Laboratory of Desert and oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences College of Resources and Environment Science Xinjiang University Cele national station of observation and research for Desert Grassland ecosystem Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences Key Laboratory of Biogeography and Bioresource in Arid Land Xinjiang Institute of Ecology and GeographyChinese Academy ofSciences University of Chinese Academy of Sciences

Desert phreatophytes are greatly dependent on groundwater, but how their root systems adapt to different groundwater depths is poorly understood. In the present study, shoot and root growths of Alhagi sparsifolia Shap. seedlings were studied across a gradient of groundwater depths. Leaves, stems and roots of different orders were measured after 120 days of different groundwater treatments. Results indicated that the depth of soil wetting front and the vertical distribution of soil water contents were highly controlled by groundwater depths. The shoot growth and biomass of A. sparsifolia decreased, but the root growth and rooting depth increased under deeper groundwater conditions. The higher ratios of root biomass, root/shoot and root length/leaf area under deeper groundwater conditions implied that seedlings of A. sparsifolia economized carbon cost on their shoot growths. The roots of A. sparsifolia distributed evenly around the soil wetting fronts under deeper groundwater conditions. Root diameters and root lengths of all orders were correlated with soil water availabilities both within and among treatments. Seedlings of A. sparsifolia produced finer first- and second-order roots but larger third- and fourth-order roots in dry soils. The results demonstrated that the root systems of desert phreatophytes can be optimized to acquire groundwater resources and maximize seedling growth by balancing the costs of carbon gain.

关键词： desert phreatophytes root system strategy groundwater depth soil water biomass partition

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Climate change, water resources and sustainable development in the arid and semi-arid lands of Central Asia in the past 30 years

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Journal of Arid Land 2019年第1期11卷 1-14页

作者： YU Yang PI Yuanyue YU Xiang TA Zhijie SUN Lingxiao Markus DISSE ZENG Fanjiang LI Yaoming CHEN Xi YU Ruide Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences research Center for Ecology and Environment of Central Asia Chinese Academy of Sciences Cele national station of observation and research for Desert-Grassland ecosystem University of Chinese Academy of Sciences Chinese Academy of Forestry State Key Laboratory of Desert and oasis Ecology Chinese Academy of Sciences Chair of Hydrology and River Basin Management Technical University of Munich School of Environment and Material Science Yantai University

The countries of Central Asia are collectively known as the five "-stans": Uzbekistan, Kyrgyzstan, Turkmenistan, Tajikistan and Kazakhstan. In recent times, the Central Asian region has been affected by the shrinkage of the Aral Sea, widespread desertification, soil salinization, biodiversity loss, frequent sand storms, and many other ecological disasters. This paper is a review article based upon the collection, identification and collation of previous studies of environmental changes and regional developments in Central Asia in the past 30 years. Most recent studies have reached a consensus that the temperature rise in Central Asia is occurring faster than the global average. This warming trend will not only result in a higher evaporation in the basin oases, but also to a significant retreat of glaciers in the mountainous areas. Water is the key to sustainable development in the arid and semi-arid regions in Central Asia. The uneven distribution, over consumption, and pollution of water resources in Central Asia have caused severe water supply problems, which have been affecting regional harmony and development for the past 30 years. The widespread and significant land use changes in the 1990 s could be used to improve our understanding of natural variability and human interaction in the region. There has been a positive trend of trans-border cooperation among the Central Asian countries in recent years. International attention has grown and research projects have been initiated to provide water and ecosystem protection in Central Asia. However, the agreements that have been reached might not be able to deliver practical action in time to prevent severe ecological disasters. Water management should be based on hydrographic borders and ministries should be able to make timely decisions without political intervention. Fully integrated management of water resources, land use and industrial development is essential in Central Asia. The ecological crisis should provide

关键词： Central Asia climate change water resources arid and semi-arid lands land use changes sustainable development socio-economic development

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Vegetation fractional coverage change in a typical oasis region in Tarim River Watershed based on remote sensing

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Journal of Arid Land 2013年第1期5卷 89-101页

作者： Fei ZHANG Tashpolat TIYIP JianLi DING Mamat SAWUT Verner Carl JOHNSON NigaraTASHPOLAT DongWei GUI College of Resources and Environment Science Xinjiang University Urumqi 830046 China Key Laboratory of oasis Ecology Xinjiang University Urumqi 830046 China Department of Physical and Environmental Sciences Colorado Mesa University Grand Junction Colorado 81501 USA Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Cele national station of observation & research for Desert-Grassland ecosystem in Xinjiang Cele 848300 China

Vegetation fractional coverage （VFC） is an important index to describe and evaluate the ecological system. The vegetation index is widely used to monitor vegetation coverage in the field of remote sensing （RS）. In this paper, the author conducted a case study of the delta oasis of Weigan and Kuqa rivers, which is a typical saline area in the Tarim River Watershed. The current study was based on the TM/ETM＋ images of 1989, 2001, and 2006, and supported by Geographic Information System （GIS） spatial analysis, vegetation index, and dimidiate pixel model. In addition, VBSl （vegetation, bare soil and shadow indices） suitable for TM/ETM＋ irrlages, constructed with FCD （forest canopy density） model principle and put forward by ITTO （International Tropical Timber Organization）, was used, and it was applied to estimate the VFC. The estimation accuracy was later prow^n to be up to 83.52%. Further, the study analyzed and appraised the changes in vegetation patterns and revealed a pattern of spatial change in the vegetation coverage of the study area by producing the map of VFC levels in the delta oasis. Forest, grassland, and farmland were the three main land-use types with high and extremely-high coverage, and they played an important role in maintaining the vegetation. The forest area determined the changes of the coverage area, whereas the other two land types affected the directions of change. Therefore, planting trees, protecting grasslands, reclaiming farmlands, and controlling unused lands should be included in a long-term program because of their importance in keeping regional vegetation coverage. Finally, the dynamic variation of VFC in the study area was evaluated according to the quantity and spatial distribution rendered by plant cover diigital images to deeply analyze the reason behind the variation.

关键词： vegetation fractional coverage (VFC) VBSI (vegetation, bare soil and shadow indices) dimidiate pixel model delta oasis of Weigan and Kuqa rivers

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