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Wien Effect Characterization of Interactions Between Ions and Charged Sites on Clay Surfaces of Variable-Charge soils

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Pedosphere 2009年第5期19卷 545-553页

作者： ZHU Hao-Wen WANG Yu-Jun ZHOU Jun JIANG Jun LI Cheng-Bao ZHOU Dong-Mei S. P. FRIEDMAN key laboratory of {2. Environment and Pollution Remediation Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) state key {2. of soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) Institute of soil Water and Environmental Sciences Agricultural Research Organization the Volcani Center Bet Dagan 50250 (Israel)

To investigate the interactions of oppositely charged sites on the surfaces of variable-charge soil particles with cations and anions, and to evaluate the mean Gibbs free binding and adsorption energies of various cations on particles of red soil and latosol, clay fractions smaller than 2.μm were separated from samples of the two variable-charge soils. Ferric oxides were removed from part of the clay fractions, which were then saturated with various chlorides （NaC1, KCl, CaCl2. CdCl2.or LaCl3）. Electrical conductivities （EC） of dilute suspensions of the original and of the iron oxides-free clay fractions in deionized water were measured with the SHP-2.short high-voltage pulse apparatus, which enables measurement of the Wien effect at field strengths （E） from 14 to 2.0 kV cm^-1. The Wien effect （EC-E） curves revealed EC increases of red soil suspensions between 14 and 2.0 kV cm^-1, of 8.3, 8.4, 12.1, 5.9, and 1.2.μS cm^-1 for NaCl, KCl, CaCl2. CdCl2. and LaCl3, respectively, reflecting the differing interactions with the various cations and chloride. The EC increments with the iron-free red soil suspensions were higher, being 2..7, 17.2. and 15.3 μS cm^-1 for NaCl, CaCl2. and CdCl2. respectively. In the natural latosol suspensions the EC increments were practically zero, whereas in the iron-free fractions there were significant EC increments of 10.3, 5.7, 5.0, and 1.6μS cm^-1 for NaCl, CaCl2. CdCl2. and LaCl3, respectively.

关键词： electrical conductivity field strength iron oxide overlapping ζ potential

Estimating surface evapotranspiration using combined MODIS and CBERS-02.data

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Science china(Technological sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2. LIU Qinhuo1, TANG Yong1,3, TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2. ZHENG Hongsheng4 & CHEN Jiayi4 1. state key {2. of Remote Sensing Science, Institute of Remote Sensing Applications, chinese academy of sciences, Beijing 100101, china 2. Research Center for Remote Sensing and GIS, Department of Geography, Beijing Normal University, Beijing 100875, china 3. Graduate University of chinese academy of sciences, Beijing 100039, china 4. Department of Atmospheric Physics, Peking University, Beijing 100871, china 1. state key {2. of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China2. Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China3. Graduate University of Chinese Academy of Sciences 100039 Beijing China4. Department of Atmospheric Physics Peking University 100871 Beijing China

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1km resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02.data were used to produce land use class of Baiyangdian area, Hebei Province, china in the autumn of 2.04. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the theoretical analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

Mineral Coated Fertilizer Effect on Nitrogen-Use Efficiency and Yield of Wheat

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Pedosphere 2005年第4期15卷 526-531页

作者： LI Jian-Yun HUA Quan-Xian TAN Jin-Fang ZHOU Jian-Min HOU Yan-Lin L Department of soil Environmental Science Research Center for Eco-Environmental Science Chinese Academy of Sciences Beijing 100085 （China）. state key {2. of soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China） Graduate School of the chinese academy of sciences Beijing 100039 （China） College of Agriculture Henan Agricultural University Zhengzhou 450002 （China）

A field experiment with winter wheat （Triticum aestivurn L.） was conducted on a silt loam calcaric endorusti-ustic Cambosols derived from the Yellow River alluvial deposits in Henan, china, from 2.01 to 2.02.to evaluate N recovery and agronomic performance of different mineral coated fertilizers （MiCFs） compared to normal urea used in wheat cropping systems under field conditions. Five treatments, including CK （check, no N fertilizer）, urea and three different MiCFs at an equivalent N application rate were established in a randomized complete block design. N release from MiCFs in soil was more synchronous with the N requirement of wheat throughout the growth stages than that from urea, with grain yield of the MiCF treatments significantly higher （P 〈 0.05） than that of the treatment urea. Correspondingly, the N recovery rate was greater for all MiCFs compared to urea, increasing from 32.8% up to 50.1%. Due to its high recovery and low cost, use of the mineral coated N fertilizers was recommended instead of the polymer coated N fertilizers.

关键词： mineral coated fertilizer N recovery urea winter wheat

Simulation of dam breach development for emergency treatment of the Tangjiashan Quake Lake in china

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Science china(Technological sciences) 2008年第S2期51卷 82-94页

作者： WANG GuangQian,LIU Fan,FU XuDong & LI TieJian state key {2. of Hydroscience and engineering,Tsinghua University,Beijing 100084,china state key {2. of Hydroscience and engineering Tsinghua University Beijing 100084 China

The Tangjiashan Quake Lake is the largest quake lake triggered by the 5.12.Wenchuan Earthquake that happened on May 12.2.08 in china,posing high risk of catastrophic flash flood hazards to downstream human life and properties.A physics-based numerical simulation approach is proposed for real-time prediction of dam breach development of the Tangjiashan Quake Lake in the case of emergency *** erosion and lateral development of the dam breach are represented through accounting for the underlying physics including selective sediment transport and gravitational *** breach erosion model that involves few parameters enables quick calibration based on the monitored hydrological data in emergency analysis where fully geotechnical information about the barrier dam is not *** process of dam breach development is found to be nonlinear in cascades due to the combined effects of headcutting and bank *** agreement between the simulation results and the observed data shows the applicability of the present approach for emergency analysis of quake *** will arise in the situation where the soil composition of barrier dam is significantly *** of circular arc failure for cohesive soil and lateral seepage in bank slope will also enhance its applicability to complex situations.

关键词： quake lake earthquake dam breach simulation numerical model erosion collapse headcutting

Thermal and Mechanical Analysis of Ground Freezing Method Applied to Subway Tunnel

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Thermal and Mechanical Analysis of Ground Freezing Method Ap...

Vertical　fluxes　of　volatile　mercury　over　soil　surfaces　in　Guizhou　Province,china

第八届国际冻土工程会议

作者： Shuangyang Li Shujuan Zhang Mingyi Zhang Erxiang Zhao (state key {2. of frozen soil engineering Cold and Arid Regions Environmental and engineering Research Institute chinese academy of sciences lanzhou Gansu 73.000 {12.)

＜正＞Although controlled ground freezing for construction and mining application has been in use for more than several decades,the literatures concerning about this aspect have mainly concentrated on engineering technique and indoor test instead of theoretical calculations and analyses up to *** order to provide theoretical reference for engineering practice,in this paper,a subway tunnel in Guangzhou,constructed by employing ground freezing method as an auxiliary engineering method,is taken as an example to analyze thermal and mechanical states of soils and linings during tunnel *** first,based on the governing differential equations of the transient temperature field with phase change and heat of hydration of cement,the temperature fields at every excavation stage are computed and analyzed by using finite element ***, according to the distribution feature of the temperature field at every excavation stage and corresponding mechanical parameters decided by this temperature field,the stresses and settlements of soils during corresponding excavation stage are also analyzed through using creep constitutive model for frozen soil and elastoplastic constitutive model for unfrozen *** last,the safety of frozen earth wall is evaluated by applying long-term strength equation of frozen *** results show that,if ground freezing method is used to constructed subway tunnel,the surface settlements will be controlled effectively.

关键词： ground freezing method tunnel temperature field stress settlement

来源： cnki会议评论

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Journal of Environmental sciences 1997年第2期9卷 116-120页

作者： Feng Xinbin, Chen Yecai, Zhu Weiguo state key {2. of Environmental Geochemistry, Institute of Geochemistry, chinese academy of sciences, Guiyang 550002. china

An instrument that can be used to measure the fluxes of volatile mercury over soil surface in field was set up. From August to October in 1993, the fluxes of volatile mercury over soil surfaces at 5 sites of three different areas(high mercury area, mercury polluted area, and reference area) were measured. The results showed that the measured fluxes over soil surface during daytime were higher than those measured at night, and that the flux of volatile mercury over soil surface has relationship with both the total mercury contents of soil and air temperature.

关键词： mercury fluxes flux chamber Guizhou Province Danzhai Mercury Mine.

Spatial patterns of ecosystem carbon residence time in chinese forests

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中国科学：地球科学英文版 2010年第8期53卷 1229-1240页

作者： ZHOU Tao1,2. SHI PeiJun1,2. JIA GenSuo3, LI XiuJuan1,2.& LUO YiQi4 1 state key {2. of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, china 2.academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs & Ministry of Education, Beijing 100875, china 3 key {2. of Regional Climate-Environment Research for Temperate East Asia, chinese academy of sciences, Beijing 10002., china 4 Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA 1. state key {2. of Earth Surface Processes and Resource Ecology Beijing Normal University Beijing 100875 China2. Academy of Disaster Reduction and Emergency Management Ministry of Civil Affairs & Ministry of Education Beijing 100875 China3. Key Laboratory of Regional Climate-Environment Research for Temperate East Asia Chinese Academy of Sciences Beijing 100029 China4. Department of Botany and Microbiology University of Oklahoma Norman OK 73019 USA

Capacity of carbon sequestration in forest ecosystem largely depends on the trend of net primary production (NPP) and the length of ecosystem carbon residence time. Retrieving spatial patterns of ecosystem carbon residence time is important and necessary for accurately predicting regional carbon cycles in the future. In this study, a data-model fusion method that combined a process-based regional carbon model (TECO-R) with various ground-based ecosystem observations (NPP, biomass, and soil organic carbon) and auxiliary data sets (NDVI, meteorological data, and maps of vegetation and soil texture) was applied to estimate spatial patterns of ecosystem carbon residence time in {2. forests at steady state. In the data-model fusion, the genetic algorithm was used to estimate the optimal model parameters related with the ecosystem carbon residence time by minimizing total deviation between modeled and observed values. The results indicated that data-model fusion technology could effectively retrieve model parameters and simulate carbon cycling processes for {2. forest ecosystems. The estimated carbon residence times were highly heterogenous over china, with most of regions having values between 2. and 70 years. The deciduous needleleaf forest and the evergreen needleleaf forest had the highest averaged carbon residence times (73.8 and 71.3 years, respectively), the mixed forest and the deciduous broadleaf forest had moderate values (38.1 and 37.3 years, respectively), and the evergreen broadleaf forest had the lowest value (31.7 years). The averaged carbon residence time of forest ecosystems in china was 57.8 years.

关键词： carbon residence time carbon cycle forest ecosystem data-model fusion inverse modeling genetic algorithm

Overexpression of a Foreign Bt Gene in Cotton Affects the Low-Molecular-Weight Components in Root Exudates

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Pedosphere 2007年第3期17卷 324-330页

作者： YAN Wei-Dong SHI Wei-Ming LI Bao-Hai ZHANG Min state key {2. of soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing210008 （China）

Most research in the past using genetically modified crops (GM crops) has focused on the ecological safety of foreign gene (i.e., the gene flow), gene products (for example, Bt (Bacillus thuringiensis) protein), and the safety of transgenic food for humans. In this study, changes in both the species and amounts of low-molecular-weight components in cotton (Gossypium hirsutum L.) root exudates after foreign Bt gene overexpression were investigated under different nutritional conditions. Transgenic cotton containing Bt (Bt-cotton), supplemented with all the mineral nutrients, secreted more organic acids than the wild-type cotton (WT). When nitrogen was removed from the full-nutrient solution, the amount of organic acids secretion of Bt-cotton was lesser than that of WT. The roots of the transgenic cotton secreted lesser amounts of amino acids and soluble sugars than the WT roots in the full-nutrient solution. Deficiencies of P and K caused a large increase in the total amino acid and soluble sugar secretions of both Bt-cotton and WT, with larger increases observed in Bt-cotton. Because transferring the foreign Bt gene into cotton can result in alterations in the components of the root exudates, with the effect varying depending on the nutritional status, the cultivation of genetically modified crops, such as Bt-cotton, in soil environments should be more carefully assessed, and the possible effects as a result of the alterations in the root exudate components should be considered.

关键词： gene overexpression low-molecular-weight components nutritional status root exudates transgenic cotton

Nitrate and Ammonium Leaching in Variable-and Permanent-Charge Paddy soils

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Pedosphere 2010年第2期20卷 209-216页

作者： XIONG Zheng-Qin HUANG Tai-Qing MA Yu-Chun XING Guang-Xi ZHU Zhao-Liang College of Resources and Environmental sciences Nanjing Agricultural University Nanjing 210095 （China） state key {2. of soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of SciencesNanjing 210008 （China）

A variable-charge （VC） and a permanent-charge paddy soil （PC） were selected to study nitrate-N （NO3^--N） and ammonium-N （NH4^＋-N） leaching with N isotopes for one consecutive year. An irrigation and intermittent drainage pattern was adopted to mimic natural occurrence of rainfall during the upland crop season and drainage management during the flooded rice season. Treatments to each soil type were no-N controls （CK）, ^15N-labeled （NH4）2.O4 （NS）, and milk vetch （NV） applied at a rate equivalent to 2.8 kg N ha^-1 to unplanted lysimeters, totaling six treatments in triplicates. Results indicated that the soil type dominated N leaching characteristics. In the case of PC, NO3^--N accounted for 78% of the total leached inorganic N; NS was prone to leach three times more than the NV, being 8.2. and 2.4% of added ^15N respectively; and 〉 85% of leached NO3-N came from of the total inorganic N in leachate. Moreover, NH4^＋-N native N in the soil. In the case of VC, NH4^＋-N made up to 92. leaching was detected throughout the whole incubation, and was particularly high during the flooded season. NO3^--N leaching in VC occurred later at a lower rate compared to that in PC. The findings of this study indicate that NO3^--N leaching during the drained season in permanent-charge paddy soils and NH4^＋-N leaching in variable-charge soils deserve more attention for regional environmental control.

关键词： drained/flooded rotations fertilizer-derived nitrate ion movement lysimeter ^15N tracing technique