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Assessment of Soil Water Content in Field with Antecedent Precipitation Index and groundwater depth in the Yangtze River Estuary

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Journal of Integrative Agriculture 2013年第4期12卷 711-722页

作者： XIE Wen-ping YANG Jing-song State Key Laboratory of Soil and Sustainable Agriculture/Institute of Soil Science Chinese Academy of Sciences

To better understand soil moisture dynamics in the Yangtze River Estuary （YRE） and predict its variation in a simple way, a field monitoring experiment was carried out along the north branch of the Yangtze River, where seawater intrusion was strong and salt-water variation is one of the limiting factors of local agriculture. In present paper, relation between antecedent precipitation index （API） and soil water content is studied, and effects of groundwater depth on soil water content was analyzed. A relatively accurate prediction result of soil water content was reached using a neural network model. The impact analysis result showed that the variation of the API was consistent with soil water content and it displayed significant correlations with soil water content in both 20 and 50 cm soil layer, and higher correlation was observed in the layer of 20 cm. groundwater impact analysis suggested that soil moisture was affected by the depth of groundwater, and was affected more greatly by groundwater at depth of 50 cm than that at 20 cm layer. By introducing API, groundwater depth and temperature together, a BP artificial network model was established to predict soil water content and an acceptable agreement was achieved. The model can be used for supplementing monitoring data of soil water content and predicting soil water content in shallow groundwater areas, and can provide favorable support for the research of water and salt transport in estuary area.

关键词： antecedent precipitation index groundwater depth soil water content assessment

Effect of groundwater depth on riparian plant diversity along riverside-desert gradients in the Tarim River

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Journal of Plant Ecology 2019年第3期12卷 564-573页

作者： Yong Zeng Chengyi Zhao Jun Li Yan Li Guanghui Lv Tong Liu State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences818 South Beijing RoadUrumqi 830011China College of Resources and Environment Sciences Xinjiang University14 Shengli RoadUrumqi 830046China University of Chinese Academy of Sciences 55 East Zhongguancun East RoadBeijing 100049China Land Science Research Center Nanjing University of Information Science&Technology219 Ningliu RoadNanjing 210044China College of Life Sciences Shihezi University4 North RoadShihezi 832003XinjiangChina

Aims Riparian plant diversity is sensitive to changes in groundwater in arid regions.However,little is known about how plant diversity responds to changes in environment along riverside-desert gradi-ents in riparian ecosystem.Our objectives were to(i)identify ri-parian plant diversity along riverside-desert gradients in Tarim desert riparian forests,(ii)analyze the impact of environment variables on plant diversity,(iii)determine the optimum groundwater depth for different plant life-forms.Methods Six transects 90 quadrats(with each size 100 m×100 m)distributed vertically to river bed along riverside-desert gradients~30 km in length were surveyed.At each quadrat,the morphological features of riparian plant communities were measured,and the groundwater depth,soil water,soil salinity,soil nutrient were also monitored at same sites.Important Finding Three distinct vegetation communities were identified based on cover and richness in the tree,shrub and herb layers:the riparian zone,the transitional zone and the desert margin zone.Twelve spe-cies were indicators of the three vegetation communities.Riparian plant diversity was influenced by groundwater depth,distance from river,soil moisture content,soil salinity and soil nutrient by redundancy analysis.In response to groundwater depth,the op-timal groundwater depths for species diversity,evenness and shrub cover were 2.8,2.7 and 3.7 m,respectively.Therefore,maintaining high plant diversity requires managers to ensure stable groundwater depth for different plant life-forms rather than for some of them.

关键词： vegetation community distance from river groundwater depth Tarim River

Influence of groundwater depth on species composition and community structure in the transition zone of Cele oasis

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Journal of Arid Land 2010年第4期2卷 235-242页

作者： Frank M. THOMAS Department of Geobotany University of Trier Behringstraβe 21 54296 Trier Germany

The paper analyzes the hypothesis that the distribution of dominant plant species and characteristics of plant communities are related to groundwater depth. The results showed that variations of groundwater depth impacted distributions and characteristics of dominant plant communities. However, besides groundwater depth, the community composition and species diversity were also influenced by physiognomy of the habitat. Based on the similarity coefficient, the differences between dominant plant communities were significant at different groundwater depths. Compared with other results relating to desert vegetation and groundwater depth, variations of community distribution were similar at the large spatial scale. However, in this extremely arid region, there were significant differences in community type and community succession when compared with other arid regions, especially in relationship to deep groundwater depth. With groundwater depth from deep to shallow, communities transformed with the sequence of Alhagi communities, Tamarix spp. communities, Populus communities, Phragmites communities, and Sophora communities. At groundwater depth of less than 6.0 m, the community type and composition changed, and the species diversity increased. Among these dominant species, Tamarix exhibited the biggest efficiency in resource utilization according to niche breadth, which means it possessed the best adaptability to environmental conditions at the oasis margins.

关键词： groundwater depth community characteristic niche breadth oases Taklamakan desert

Increased salinity and groundwater levels lead to degradation of the Robinia pseudoacacia forest in the Yellow River Delta

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Journal of Forestry Research 2022年第4期33卷 1233-1245页

作者： Chaoxia Lu Chen Zhao Jing Liu Kailun Li Baoshan Wang Min Chen Shandong Provincial Key Laboratory of Plant Stress Research College of Life ScienceShandong Normal UniversityJi’nan 250014People’s Republic of China Shandong Provincial Key Laboratory of Crop Genetic Improvement Ecology and PhysiologyShandong Academy of Agricultural SciencesJi’nan 250100People’s Republic of China

Forest degradation is a worldwide problem,although its causes vary due to geographical and climatic differences and man-made causes.In recent years,the Robinia pseudoacacia forest in the Yellow River Delta has suffered severe degradation.The causative mechanisms were investigated in the field over two years,and the results show that increased forest degradation was reflected by increased tree mortality,high leaf and soil sodium salt levels and groundwater depth.Average tree diameters decreased,and leaf chlorophyll and soil microbial contents decreased.Redundancy discriminate analysis(RDA)showed that degradation of the forest was correlated positively with soil salt content,but negatively with groundwater depth.Correlation analysis showed that 0.79%–0.95%soil salt content and above 1.20 m groundwater depth caused the death of R.pseudoacacia trees due to localized anthropogenic economic activities,such as rice farming,that disrupted the original water–salt balance.Measures are recommended to prevent further degradation and restore degraded forests.

关键词： Forest degradation groundwater depth Robinia pseudoacacia forest Soil salt content The Yellow River Delta

Changes in groundwater levels and the response of natural vegetation to transfer of water to the lower reaches of the Tarim River

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Journal of Environmental Sciences 2007年第10期19卷 1199-1207页

作者： XU Hai-liang YE Mao LI Ji-mei Xinfiang Institute of Ecology and Geography Research Chinese Academic of Science Urumqi 830011 China School of Geography Sciences and Touristy Xinfiang Normal University Urumqi 830054 China

Restoration and reconstruction of the degraded Tarim River ecosystem is an important challenge. A goal of an ecological water conveyance project is to protect and restore the natural vegetation in the lower reaches of Tadm River by transferring water from Bosten Lake, through the river channel, to the lower reaches. This study describes the changes in groundwater depth during the water transfer and the respondence of riparian vegetation to alterations in groundwater levels. The results indicate that groundwater depth along the Tarim River channel has a significant spatial-temporal component. groundwater levels closest to the river channel show the most immediate and pronounced changes as a response to water transfer while those further away respond more slowly, although the observed change appears to be longer in duration. With a rise in the groundwater level, natural vegetation responded with higher growth rates, biomass and biodiversity. These favorable changes show that it is feasible to protect and restore the degraded natural vegetation by raising the groundwater depth. Plant communities are likely to reflect the hysteresis phenomenon, requiting higher water levels to initiate and stimulate desired growth than what may be needed to maintain the plant community. Because different species have different ecologies, including different root depths and densities and water needs, their response to increasing water availability will be spatially and temporally heterogenous. The response of vegetation is also influenced by microtopography and watering style. This paper discusses strategies for the protection and restoration of the degraded vegetation in the lower reaches of the Tarim River and provides information to complement ongoing theoretical research into ecological restoration in add or semi-arid ecosystems.

关键词： the lower reaches of Tarim River ecological watering conveyance groundwater depth ecological response natural vegetation

Temporal and spatial variations of net primary productivity and its response to groundwater of a typical oasis in the Tarim Basin, China

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Journal of Arid Land 2021年第11期13卷 1142-1154页

作者： SUN Lingxiao YU Yang GAO Yuting ZHANG Haiyan YU Xiang HE Jing WANG Dagang Ireneusz MALIK Malgorzata WISTUBA YU Ruide 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 100049China Cele National Station of Observation and Research for Desert-Grassland Ecosystems Cele 848300China University of Silesia in Katowice Institute of Earth SciencesPolish-Chinese Centre for Environmental ResearchBankowa 1240-007 KatowicePoland School of Environment and Material Engineering Yantai UniversityYantai 264005China

Net primary productivity (NPP) of the vegetation in an oasis can reflect the productivity capacity of a plant community under natural environmental conditions. Owing to the extreme arid climate conditions and scarce precipitation in the arid oasis regions, groundwater plays a key role in restricting the development of the vegetation. The Qira Oasis is located on the southern margin of the Taklimakan Desert (Tarim Basin, China) that is one of the most vulnerable regions regarding vegetation growth and water scarcity in the world. Based on remote sensing images of the Qira Oasis and daily meteorological data measured by the ground stations during the period 2006-2019, this study analyzed the temporal and spatial patterns of NPP in the oasis as well as its relation with the variation of groundwater depth using a modified Carnegie Ames Stanford Approach (CASA) model. At the spatial scale, NPP of the vegetation decreased from the interior of the Qira Oasis to the margin;at the temporal scale, NPP of the vegetation in the oasis fluctuated significantly (ranging from 29.80 to 50.07 g C/(m2•month)) but generally showed an increasing trend, with the average increase rate of 0.07 g C/(m2•month). The regions with decreasing NPP occupied 64% of the total area of the oasis. During the study period, NPP of both farmland and grassland showed an increasing trend, while that of forest showed a decreasing trend. The depth of groundwater was deep in the south of the oasis and shallow in the north, showing a gradual increasing trend from south to north. groundwater, as one of the key factors in the surface change and evolution of the arid oasis, determines the succession direction of the vegetation in the Qira Oasis. With the increase of groundwater depth, grassland coverage and vegetation NPP decreased. During the period 2008-2015, with the recovery of groundwater level, NPP values of all types of vegetation with different coverages increased. This study will provide a scientific basis for the rational utilization and sustainable m

关键词： net primary productivity Carnegie Ames Stanford Approach groundwater depth land use NDVI Qira Oasis

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

Comprehensive evaluation on the ecological function of groundwater in the Shiyang River watershed

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Journal of groundwater Science and Engineering 2021年第4期9卷 326-340页

作者： Min Liu Zhen-long Nie Le Cao Li-fang Wang Hui-xiong Lu Zhe Wang Pu-cheng Zhu Institute of Hydrogeology and Environmental Geology CAGSShijiazhuang 050061China Key Laboratory of groundwater Sciences and Engineering Ministry of Natural ResourcesShijiazhuang 050061China Airborne Survey and Remote Sensing Center of Nuclear Industry Shijiazhuang 050002China.

With an arid climate and shortage of water resources,the groundwater dependent ecosystems in the oasis-desert ecotone of the Shiyang River Watershed has been extremely damaged,and the water crisis in the oasis has become a major concern in the social and the scientific community.In this study,the degene-ration characteristics of the groundwater ecological function was identified and comprehensive evaluated,based on groundwater depth data,vegetation quadrat and normalized difference vegetation index(NDVI)from Landsat program.The results showed that(1)the suitable groundwater depth for sustainable ecology in the Shiyang River Watershed is about 2-4 m;(2)the terms of degenerative,qualitative and disastrous stages of the groundwater ecological function are defined with the groundwater depths of about 5 m,7 m and 10 m;(3)generally,the groundwater ecological function in the oasis-desert ecotone of the lower reaches of Shiyang River Watershed is weak with an area of 1397.9 km2 identified as the severe deterioration region,which accounted 74.7%of the total area.In the meantime,the percentages of the good,mild and moderate deterioration areas of groundwater ecological function are 3.5%,5.5%and 16.3%,respectively,which were mainly distributed in the Qingtu lake area and the southeastern area of the Shoucheng town;(4)the degradation and shrinkage of natural oasis could be attributed to the dramatic groundwater decline,which is generally caused by irrational use of water and soil resources.This study could provide theoretical basis and scientific support for the decision-making in environmental management and ecological restoration of the Shiyang River Watershed.

关键词： Oasis-desert ecotone groundwater depth Normalized difference vegetation index(NDVI) Desert vegetation Degenerative change-qualitative change-disaster stages

Photosynthesis of Populus euphratica and its response to elevated CO2 concentration in an arid environment

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Progress in Natural Science:Materials International 2009年第4期19卷 443-451页

作者： Honghua Zhou a,b,c, Yaning Chena,b, Weihong Li a,b, Yapeng Chen a,b, Lixin Fud a Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, China b Key Laboratory of Oasis Ecology and Desert Environment, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China c Graduate School of Chinese Academy of Sciences, Beijing 100039, China d College of Natural Resources and Environment Science of Xinjiang Agricultural University, Urumqi 830052, China Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences 818 South Beijing Road Urumqi Xinjiang 830011 China Key Laboratory of Oasis Ecology and Desert Environment Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Graduate School of Chinese Academy of Sciences Beijing 100039 China College of Natural Resources and Environment Science of Xinjiang Agricultural University Urumqi 830052 China

The photosynthetic characterization of Populus euphratica and its response to the elevated carbon dioxide concentration ([CO2]) were analyzed based on its net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), and water use effciency (WUE) at different groundwater depths measured by a portable gas exchange system (LI-6400) in the lower reaches of the Tarim River. The results showed that the elevation of [CO2] decreased the gs, and increased the Pn, Ci and WUE of P. euphratica. However, the effects of the elevated [CO2] on gs, Pn, Ci and WUE varied considerably with groundwater depth. The response of photosynthesis to rising [CO2] was stronger at the greater groundwater depth (more than 6 m) than that at the shallower groundwater depth (less than 6 m). The critical groundwater depth required to maintain the normal survival of P. euphratica was less than 6 m. When the groundwater depth increased to more than 6 m, P. euphratica encountered moderate water stress, and the plant suffered severe water stress when the groundwater depth increased to more than 7 m.

关键词： Photosynthesis Populus euphratica groundwater depth CO2 concentration The lower reaches of the Tarim River