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Seasonal patterns in water uptake for Medicago sativa grown along an elevation gradient with shallow groundwater table in Yanchi county of Ningxia,Northwest China

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Journal of Arid Land 2016年第6期8卷 921-934页

作者： ZHU Lin ZHANG Huili GAO Xue QI Yashu XU Xing State Key Laboratory Breeding Base of Land Degradation and Ecological Restoration of North-western China Ningxia University Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem of North-western China Ministry of EducationNingxia University Agricultural College Ningxia University

Lucerne （Medicago sativa L.） is a deep-rooted perennial leguminous forage with high evapo-transpiration rate exceeding the annual precipitation in semi-arid areas of Northwest China. groundwater might be the potential water sources of lucerne in the area with shallow groundwater table. In this study, stable isotopic compositions of oxygen and hydrogen （6180 and 8D） of different water sources and xylem sap were analyzed to determine the seasonal （April, June, July and August） and topographic （three slope positions） variations in water sources for lucerne growing in Ningxia eastern semi-arid area adjacent to Mu Us Desert characterized by shallow groundwater table. IsoSource software was used to calculate the probable contribution of different water sources to the total plant water uptake. Stomatal conductance, stem water potential, carbon isotope discrimination （A13C） of whole plant were also determined for evaluating the water status of lucerne growing at different slope positions. The results showed that soil water content increased as the elevation decreased. Oxygen compositions of soil water in the 0-40 cm profile fluctuated considerably. Soil water 8180 values in deep profile （〉3.5 m） were similar to those in groundwater, implying the recharge of groundwater to this soil layer. Highest water utilization rate from deep soil profile （below 350 cm） was recorded for lucerne grown at the slope position 1 （groundwater table depth of 3.5-3.9 m） in April, June and July. The lucernes at slope position 2 （groundwater table depth of 5.8-6.4 m） and slope position 3 （groundwater table depth 7.1-8.3 m） mostly used water from deep soil layers （below 350 cm） during dry period, and turned to use water from superficial soil layer in wet period. Higher yield, A13C value of whole plant and stomatal conductance were observed for lucerne grown at the slope position 1 than those at other slope positions. These results indicated that groundwater is a significant water source for transpi

关键词： lucerne water uptake groundwater table oxygen and hydrogen isotopic compositions evapo-transpiration

Understanding groundwater table using a statistical model

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Water Science and Engineering 2018年第1期11卷 1-7页

作者： Shao-feng Yan Shuang-en Yu Yu-bai Wu De-feng Pan Jia-gen Dong Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment in Southern China Ministry of EducationHohai UniversityNanjing 210098China Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute Wuhan 430064China Jiangsu Water Conservancy Research Institute Nanjing 210017China Jiangsu Coastal Water Conservancy Research Institute Dongtui 224200China Jiangsu Province Hydrology and Water Resources Investigation Bureau Nanjing 210008China

In this study, a statistical model was established to estimate the groundwater table using precipitation, evaporation, the river stage of the Liangduo River, and the tide level of the Yellow Sea, as well as to predict the groundwater table with easily measurable climate data in a coastal plain in eastern China. To achieve these objectives, groundwater table data from twelve wells in a farmland covering an area of 50 m ~ 150 m were measured over a 12-month period in 2013 in Dongtai City, Jiangsu Province. Trend analysis and correlation analysis were conducted to study the patterns of changes in the groundwater table. In addition, a linear regression model was established and regression analysis was conducted to understand the relationships between precipitation, evaporation, river stage, tide level, and groundwater table. The results are as follows：（1） The groundwater table was strongly affected by climate factors （e.g., precipitation and evaporation）, and river stage was also a significant factor affecting the groundwater table in the study area （p 〈 0.01, where p is the probability value）. （2） The groundwater table was especially sensitive to precipitation. The significance of the factors of the groundwater table were ranked in the following descending order： precipitation, evaporation, and river stage. （3） A triple linear regression model of the groundwater table, precipitation, evaporation, and river stage was established. The linear relationship between the groundwater table and the main factors was satisfied by the actual values versus the simulated values of the groundwater table （R^2 = 0.841, where R^2 is the coefficient of determination）.

关键词： groundwater table Precipitation Evaporation Climate factors Regression statistics Coastal plain

Physiological responses of Populus euphratica Oliv. to groundwater table variations in the lower reaches of Heihe River, Northwest China

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Journal of Arid Land 2012年第3期4卷 281-291页

作者： Yang ZHAO ChuanYan ZHAO ZhongLin XU YiYue LIU Yao WANG Chao WANG HuanHua PENG XiangLin ZHENG State Key Laboratory of Pastoral Agricultural Ecosystem Institute of Arid Agroecology School of Life Science Lanzhou Uni-versity Lanzhou 730000 China MOE Key Laboratory of Oasis Ecology College of Resource and Environmental Science Xinjiang University Urumqi 830002China Key Laboratory of Western China's Environment Systems MOE Lanzhou University Lanzhou 730000 China

Riparian vegetation in the lower reaches of Heihe River serves important ecological functions. However, the riparian ecosystems have been constantly deteriorating in the past 30 years simply due to water interception for oasis agricultural irrigation in the middle reaches of the river. This study pays a particular attention to Populus eu- phratica Oily. forest because it is a dominant component of the riparian ecosystem in the lower reaches of Heihe River where the depth of groundwater table is the controlling factor in sustaining riparian ecosystems. To reveal leaf-related physiological responses of Populus euphratica Oliv. forest to groundwater table variations, we analyzed the relationships between the depth of groundwater table （DG） and three leaf-related parameters, i.e. leaf stomatal density （SD）, specific leaf area （SLA）, and stable carbon isotopic composition （6~SC）. Our results show that the relationship between DG and leaf SD is a bi-mode one shaped by both salt stress and water stress. That is, salt stress appeared in shallow groundwater conditions and water stress happened in deep groundwater conditions, and the thin layer around 2.7 m of DG is a stress-free layer. Leaf SD fluctuated according to the DG variation, first de- creased with increasing DG, then increased at depths ranging 2.7-3.7 m, and after a relatively stable plateau of SD at depths ranging 3.7-5.2 m, decreased again with increasing DG. Our results also show that SLA decreased ex- ponentially with increasing DG and foliar 6130 values are also strongly dependent on DG, further demonstrating that these two parameters are sensitive indicators of water stress. The exponential curve suggests that SLA is more sensitive to DG when groundwater table is shallow and 3 m seems to be a threshold beyond which SLA becomes less sensitive to DG. Foliar 613C becomes more sensitive when the groundwater table is deep and 7 m seems to be a threshold below which the 6130 signature becomes more sensitive to DG.

关键词： opulus euphratica Oily stable carbon isotopic composition stomatal density specific leaf area groundwater table

Decline of groundwater table in Beijing and recognition of seismic precursory information

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Earthquake Science 2009年第3期22卷 301-306页

作者： Mingbo Yang Yuehu Kang Qing Zhang Institute of Geographic Sciences and Natural Resource Research Chinese Academy of Sciences Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Earthquake Administration of Beijing Municipality Beijing 100080 China Beijing Beifang Middle School Beoing 100022 China

This paper quantitatively analyzed groundwater table fluctuations caused by groundwater overdraft, and probed into the possibility of drawing earthquake precursory information from groundwater table variations on the background of groundwater overdraft. Main effect factors of groundwater regime in Beijing region include groundwater extraction and rainfall. The decline of groundwater table was directly related to regional groundwater overdraft. Using the method of correlation analysis, the paper analyzed the relation between groundwater overdraft and groundwater level variations, with the aim of evaluating the effect of groundwater overdraft on water levels in observation wells and providing scientific basis for identifying seismic precursory information. The results indicate that the variations of groundwater level in slightly-affected zones of groundwater overdraft can contain some seismic precursory information, and it is possible to extract seismic precursory anomalies if proper mathematical methods are adopted to remove the trend component and annual period changes.

关键词： groundwater table overdraft correlation analysis seismic precursory anomaly

A new method to dynamically simulate groundwater table in land surface model VIC

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Progress in Natural Science:Materials International 2003年第11期 19-25页

作者： YANG Hongwei* and XIE Zhenghui(LASG, Institute of Atmospheric Physics,Chinese Academy of Sciences, Beijing 100029, China)

Soil moisture plays an important role in water and energy balance in land-atmospheric interaction, but is impacted directly by the groundwater table. Dynamic variation of the groundwater table can be described mathematically by a moving boundary problem. In this paper, the moving boundary problem is reduced to a fixed boundary problem through a coordinate transformation. A new model of groundwater table simulation is developed using the mass-lumped finite element method and is coupled with the land surface model of Variable Infiltration Capacity (VIC). The simulation results show that the new model not only can simulate the groundwater table dynamically, but also can evade the choice of water table depth scale in computation with a low computation cost.

关键词： land-atmospheric interactions groundwater table VIC model.

EVALUATING DECREASE OF BEARING CAPACITY OF SHALLOW SUBSOIL CONSIDERING THE RISING OF groundwater table

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EVALUATING DECREASE OF BEARING CAPACITY OF SHALLOW SUBSOIL C...

Effects of Long-Term groundwater Management and Straw Application on Aggregation of Paddy Soils in Subtropical China

岩石力学与环境岩土工程国际会议

作者： Jian Zhou Jianping Sun Xuyang Hu Tongji University Shanghai 200092 P.R.China

＜正＞Based On soil property and limit equilibrium theory,the relation between the rising of groundwater table and the decrease of bearing capacity of the shallow sandy and clayey soil foundation is discussed in this paper,it is found that the value of bearing capacity will decrease as much as 70%for sandy soil as the groundwater table rises.A approach to determine the maximum influence depth has also been given.

关键词： groundwater table Bearing capacity

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Pedosphere 2015年第3期25卷 386-391页

作者： YIN Li-Chu ZHANG Lei YI Ya-Nan LUO Lan-Fang College of Resources and Environment Hunan Agricultural University

Soil organic carbon （SOC） and iron （Fe）-oxides are important contributors of aggregate stability in highly weathered soils, and they are influenced by groundwater management and straw application. A 30-year plot experiment with early rice （Oryza sativa L.）-late rice-winter fallow rotations was conducted using a upland clay soil in cement pools under shallow groundwater table at a depth of 20 am （SGT） aud deep groundwater table at a depth of 80 cm （DGT） to simulate the groundwater tables of two types of important paddy soils, gleyed paddy soils and hydromorphic paddy soils, respectively, in subtropical China. Soil redox potential （Eh） was measured in situ, and 0-20 cm soil samples were collected for the analyses of soil Fe-oxides, SOC, and aggregates under SGT or DGT with different straw application treatments, in order to evaluate the interaction of groundwater management and straw application on paddy soil aggregation and the relative importance of SOC or Fe-oxides on soil aggregation. The results showed that soil Eh was restricted by irrigation, and its variation was more significant under DGT than under SGT. The decreased soil Eh or reduced drying and wetting cycles under SGT resulted in more SOC accumulation with the straw application, had no effect on soil free Fe-oxides （Fed）, significantly increased the amorphous Fe-oxide （Feo） and complex Fe-oxide contents, but decreased the crystalline Fe-oxide content （Fed-Feo）. The soils under DGT had more macroaggregates than those under SGT, but the difference decreased with the straw application. It could be concluded that soil Fe-oxides were the principal contributing factor to the aggregation of paddy soils in subtropical China and SOC was also an important contributing factor.

关键词： groundwater table Fe-oxides long-term experiment rice soil organic carbon

Spatio-Temporal Variability of Soil Salinity in Alluvial Plain of the Lower Reaches of the Yellow River——A Case Study

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Pedosphere 2011年第6期21卷 793-801页

作者： LI Kai-Li CHEN Jie TAN Man-Zhi ZHAO Bing-Zi MI Shu-Xiao SHI Xue-Zheng State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China） Graduate University of Chinese Academy of Sciences Beijing 100049 （China） Department of Geography Jiangsu Institute of Education Nanjing 210013 （China） School of Water Conservation and Environment Zhengzhou University Zhengzhou 450000 （China）

Soil salinity and hydrologic datasets were assembled to analyze the spatio-temporal variability of salinization in Fengqiu County, Henan Province, China, in the alluvial plain of the lower reaches of the Yellow River. The saline soil and groundwater depth data of the county in 1981 were obtained to serve as a historical reference. Electrical conductivity （EC） of 293 surface soil samples taken from 2 kin x 2 km grids in 2007 and 4{） soil profiles acquired in 2（108 was analyzed and used for comparative mapping. Ordinary kriging was applied to predict EC at unobserved locations to derive the horizontal and vertical distribution patterns and variation of soil salinity. groundwater table data from 22 observation wells in 2008 were collected and used as input for regression kriging to predict the maximum groundwater depth of the county in 2008. Changes in the groundwater level of Fengqiu County in 27 years from 1981 to 2008 was calculated. Two quantitative criteria, the mean error or bias （ME） and the mean squared error （MSE）, were computed to assess the estimation accuracy of the kriging predictions. The results demonstrated that the soil salinity in the upper soil layers decreased dramatically and the taxonomically defined saline soils were present only in a few micro-landscapes after 27 years. Presently, the soils with relatively elevated salt content were mainly distributed in depressions along the Yellow River bed. The reduction in surface soil salinity corresponded to the locations with deepened maximum groundwater depth. It could be concluded that groundwater table recession allowed water to move deeper into the soil profile, transporting salts with it, and thus played an important role in reducing soil salinity in this region. Accumulation of salts in the soil profiles at various depths below the surface indicated that secondary soil salinization would occur when the groundwater was not controlled at a safe depth.

关键词： electrical conductivity groundwater table kriging salinization salt content

Vegetation dynamics induced by groundwater fluctuations in the lower Heihe River Basin,northwestern China

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Journal of Plant Ecology 2011年第1期4卷 77-90页

作者： Ping Wang Yichi Zhang Jingjie Yu Guobin Fu Fei Ao Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences11ADatun RoadChaoyang DistrictBeijing 100101China Graduate University of the Chinese Academy of Sciences 19AYuquan RoadBeijing 100049China

Aims Since 2000,the environmental flow controls project has been implemented in the lower Heihe River Basin,a typical arid inland river basin in northwest China,to restore the deteriorated ecological environment in this *** aim of this study was to explore the impacts of groundwater fluctuations on vegetation *** results can be used as a reference for water resources planning and management to maintain proper environmental flows in arid *** The location(by Global Positioning System)and depth of the monitoring wells,as well as groundwater table depth and salinity were measured in situ at each site from July to August *** on the measurements of the groundwater table depth and salinity following the implementation of environmental flow controls project(EFCP)in the lower Heihe River Basin,the groundwater fluctuations during the period from 2001 to 2009 were *** statistics and Pearson’s correlation were used to analyze the relationship between vegetation changes and groundwater table ***,the spatial distributions of the groundwater table depth and salinity were interpolated using the simple kriging *** analysis was applied to the time series of integrated Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index data to identify interannual vegetation *** relationship between vegetation status and groundwater environment was investigated at different spatial scales by analyzing and comparing the time series and *** Findings(i)The groundwater table and salinity increased significantly in most of the study area with spatial *** average,the groundwater table rose;0.5 and 1.5 m in the upper and lower Ejina Basin,respectively,and the groundwater salinity increased across the study area by 0–4%.(ii)A notable correlation between the vegetation status and the groundwater table was revealed when the groundwater table depth fluctuated betwe

关键词： seasonal average NDVI groundwater table salinity Mann-Kendall method arid area