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Delineation of Site-Specific Management Zones Based on Temporal and Spatial Variability of Soil Electrical Conductivity

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Pedosphere 2007年第2期17卷 156-164页

作者： LI Yan SHI Zhou LI Feng Institute of Agricultural Remote Sensing and Information Technology Application Zhejiang University Hangzhou 310029 （China）. Institute of Land Science and Property Management College of Southeast Land Management Zhejiang University Hangzhou 310029 （China） Department of Environmental Engineering Zhejiang University Hangzhou 310029 （China）

A coastal saline field of 10.5 ha was selected as the study site and 122 bulk electrical conductivity (ECb) measurements were performed thrice in situ in the topsoil (0-20 cm) across the field using a hand held device to assess the spatial variability and temporal stability of the distribution of soil electrical conductivity (EC), to identify the management zones using cluster analysis based on the spatiotemporal variability of soil EC, and to evaluate the probable potential for site-specific management in coastal regions with conventional statistics and geostatistical techniques. The results indicated high coefficients of variation for topsoil salinity over all the three samplings. The spatial structure of the salinity variability remained relatively stable with time. Kriged contour maps, drawn on the basis of spatial variance structure of the data, showed the spatial trend of the salinity distribution and revealed areas of consistently high or consistently low salinity, while a temporal stability map indicated stable and unstable regions. On the basis of the spatiotemporal characteristics, cluster analysis divided the site into three potential management zones, each with different characteristics that could have an impact on the way the field was managed. On the basis of the clearly defined management zones it was concluded that coastal saline land could be managed in a site-specific way.

关键词： coastal saline field management zone soil electrical conductivity spatial variability temporal variability

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Blind Spots on Achilles’ Heel:The Limitations of Vulnerability and Resilience Mapping in Research

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International Journal of Disaster Risk Science 2014年第1期5卷 74-85页

作者： Jessica Heesen Daniel F.Lorenz Michael Nagenborg Bettina Wenzel Martin Voss International Center for Ethics in the Sciences and Humanities(IZEW) University of Tu¨bingen72074 TubingenGermany Disaster Research Unit(DRU) Freie Universita¨t Berlin12165 BerlinGermany Department of Philosophy University of Twente7500 AE EnschedeNetherlands

The mapping of vulnerability and resilience has become an important tool for vulnerability and resilience *** definition,maps are selective ***,the predominant methods of mapping also have *** addressing vulnerability and resilience,these limitations,barriers,and blind spots have to be taken into *** aspects cannot be easily mapped,such as specific forms of knowledge and interpretation,the processuality of vulnerability and resilience,the dynamics of social processes,the context of origin,the establishment of contingent interpretations,and so *** limitations are not only theoretically important,but also are practically significant,since maps themselves become *** are regarded as representations of reality,shape particular interpretations of vulnerability and resilience,and are used as a basis for *** the unmapped preconditions of mapping remain unconsidered,this can lead to problematic side effects.

关键词： Cartographic bias Foucault Mapping constraints Vulnerability mapping

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Electret Characteristics of Hybrid Films Consisting of Porous Polytetrafluoroethylene and Teflon Fluoroethylenepropylene with COrona Charging

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Chinese Physics Letters 2002年第12期19卷 1856-1858页

作者：陈钢进 RudiDanz 等 StateKeyLaboratoryofSiliconMaterials zhejiangUniversityHangzhou310027 ZhejiangUniversityofScienceandTechnology Hangzhou310027 FraunhoferInstituteofAppliedPolymerResearch GolmGerm

We have prepared hybrid films consisting of porous polytetrafluoroethylene (PTFE) and Teflon fluoroethylenepropylene (FEP) and we have investigated their charge dynamics of injection, transport and trapping using corona charging, isothermal and thermally stimulated surface-potential decay measurements. The results indicate that the hybrid film samples show different electret characteristics when charged through side PTFE or side FEP. The samples charged negatively through side porous PTFE show the best charge stability. Their charge dynamics differs very much from a single film. The effect of corona polarity on the electret behaviour in the hybrid film is very large. The experimental results are explained with the three structure level model of charge storage in electrets.

关键词： Polytetrafluoroethylenes

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Regeneration status of riparian tree species in two sites that differ in land-use in the Okavango Delta,Botswana

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Journal of Forestry Research 2017年第5期28卷 1073-1082页

作者： Gaolathe Tsheboeng Mike Murray-Hudson Keotshephile Kashe Okavango Research Institute

Human communities from the Okavango Delta benefit from the services and goods provided by the wetland ecosystem through its riparian vegetation. These include food and timber products used for the construction of shelter and canoes. Despite the importance of riparian tree species in the Delta, their regeneration structure is currently unknown. For riparian trees to be managed sustainably, information on the current regeneration status of the trees under different land uses is needed. The Moremi game reserve (protected area) and Seronga (communal area) were selected for this study on the regeneration of riparian tree species of Croton megalobotrys Müll. Arg, Philenoptera violacea (Klotzsch) Schrire, Senegalia nigrescens (Acacia nigrescens) Oliv and Diospyros mespiliformis Hochst. ex A. Dc. The height of each individual tree was estimated in randomly selected 30 plots (15 from each site) of 20 × 50 m for assignment to five regeneration classes: 0-0.5, 0.5-1, 1-2, 2-4 and >4 m. Linear regression was used to infer regeneration status of each species. An independent-sample Student’s t test was used to determine any significance differences in seedling density/ha and sapling density/ha between different sites at p < 0.05. Diospyros mespiliformis populations had an unstable regeneration structure in both sites, while P. violacea regeneration was stable regardless of land-use type. Croton megalobotrys and S. nigrescens had an unstable regeneration pattern in Seronga, while in Moremi it was stable; thus, the regeneration structure of C. megalobotrys and S. nigrescens is affected by land-use. This result implies that intervention is needed to conserve the two species in Seronga where the current land-use appears to be incompatible with regeneration; D. mespiliformis also needs to be conserved in both Moremi and Seronga.

关键词： Conservation Regeneration Riparian Okavango and wetlands

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An imaging spectrometer employing tunable hyperchromatic microlenses

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Light(Science & Applications) 2015年第1期4卷 33-41页

作者： Phuong-Ha Cu-Nguyen Adrian Grewe Patrik Feßer Andreas Seifert Stefan Sinzinger Hans Zappe Gisela and Erwin Sick Chair of Micro-optics Department of Microsystems EngineeringUniversity of FreiburgFreiburg 79110Germany Fachgebiet Technische Optik Institut fur Mikro-und NanotechnologienTechnische Universitat IlmenauIlmenau 98684Germany

We present the design,fabrication and characterization of hydraulically-tunable hyperchromatic lenses for two-dimensional(2D)spectrally-resolved spectral *** hyperchromatic lenses,consisting of a positive diffractive lens and a tunable concave lens,are designed to have a large longitudinal chromatic dispersion and the images of different wavelengths from each other.2D objects of different wavelengths can consequently be imaged using the tunability of the lens *** hyperchromatic lens concepts are demonstrated and their spectral characteristics as well as their functionality in spectral imaging applications are shown.

关键词： hyperchromatic lens imaging spectrometer tunable filter tunable lens

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Impacts of Soil Additives on Crop Yield and C-Sequestration in Post Mine Substrates of Lusatia,germany

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Pedosphere 2012年第3期22卷 343-350页

作者： A.RODIONOV S.NII-ANNANG O.BENS M.TRIMBORN S.SCHILLEM B.U.SCHNEIDER T.RAAB R.F.HTTL Institute of Crop Science and Resource Conservation University of BonnBonn 53115 (Germany) Faculty of Environmental Science and Process Engineering Brandenburg University of TechnologyCottbus 03046 (Ger-many) german Research Centre for Geosciences GFZ Potsdam 14473 (Germany)

Opencast lignite mining in the Lusatia region of germany has resulted in large scale landscape disturbances, which require suitable recultivation techniques in order to promote plant growth and establishment in the remaining nutrient-poor substrates with low water-holding capacity. Thus, the effects of two commercial soil additives （CSA）, a hydrophilic polymer mixed with volcanic rock flour and bentonite （a-CSA）, and digester solids from biogas plants enriched with humic acids and bentonite （b-CSA）, on soil organic carbon （SOC） storage, plant yields and root biomass were assessed after cultivating perennial crops （Dactylis 9lornerata L.） in monoculture and Helianthus annuus L.-Brassica napus L. in crop rotation systems. The CSA were incorporated into the top 20 cm soil depth using a rotary spader. The results indicated that a-CSA led to a significant increase in plant yield during the first year, and improved root biomass in the following year. As a result, SOC stocks increased, especially in the 0 10 cm soil layer. No significant sequestration of additional SOC was observed on b-CSA-amended plots at the end of both years. Bulk density values decreased in all treatments under the monoculture system. It can be concluded that application of a-CSA enhanced soil water availability for plant uptake and consequently promoted plant growth and organic carbon sequestration. The relative enrichment of organic matter without effects on water-holding capacities of b-CSA treatments suggested that it was not suitable for rapid land reclamation.

关键词： bulk density organic C inputs polyacrylate soil organic carbon water-holding capacity

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Landslide Reliability Analysis Based on Transfer Coefficient Method: A Case Study from Three Gorges Reservoir

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Journal of Earth Science 2012年第2期23卷 187-198页

作者：毕仁能 Dominik Ehret 项伟 Joachim Rohn Markus Schleier 江洎洧 Three Gorges Research Center for Geo-hazard Ministry of EducationChina University of Geosciences Department of Applied Geology University of Erlangen-Nuremberg State Office for Geology Resources and Mining of Baden-WürttembergFreiburg i.Br.Germany Faculty of Engineering China University of Geosciences

To evaluate the reliability of a landslide in a reservoir, the universal transfer coefficient method, which is popularized by the Chinese standard, is adopted as performance function in this study for：（1） common deterministic method stability evaluation; （2） reliability evaluation based on a Monte Carlo method; （3） comparison of landslide reliability under different water levels and under different correlation coefficients between soil shear strength parameters （c, Φ）, respectively with mean, standard deviation, reliability coefficient and failure probability. This article uses the Bazimen （八字门） landslide, which is located at the outlet of Xiangxi （香溪） River in the Three Gorges Reservoir, as an example to evaluate its stability and reliability under different water levels with two-dimensional deterministic and probabilistic methods. With the assumption that constant mean and normal distributed shear strength parameters （c, Φ）, correlation coefficient c, Φ=-1 based reliability analysis, compared with c, Φ=0 and 1, indicates obviously more increase of reliability index and lower standard deviation as water levels rise. To the case of a certain water level, c, Φ=-1 does not have constantly positive or negative effects on landslide reliability compared with c, Φ=0 or 1, but is associated with water level. Whereas the safety factor Fs by deterministic method, which is almost the same value as corresponding mean of safety factor from probabilistic analysis, will increase slightly as water level increases.

关键词： transfer coefficient method,Monte Carlo method water level fluctuation landslide stability reliability Three Gorges Reservoir.

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Frequency Ratio Analysis of Mass Movements in the Xiangxi Catchment, Three Gorges Reservoir Area, China

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Journal of Earth Science 2010年第6期21卷 824-834页

作者： Dominik Ehret Joachim Rohn Christian Dumperth Susan Eckstein Stefanie Ernstberger Karel Otte René Rudolph Johannes Wiedenmann 项伟毕仁能 Department of Applied Geology University of Erlangen-Nuremberg Faculty of Engineering China University of Geosciences

In 2003, the Three Gorges Project （TGP, China）, currently the world＇s largest hydroelectric power plant by total capacity, went into operation. Due to large-scale impoundment of the Yangtze River and its tributaries and also due to resettlement, extensive environmental impacts like land use change and increase of geohazards are associated with the TGP. Within the Yangtze Project, we investigate these effects for the Xiangxi （香溪） catchment which is part of the Three Gorges Reservoir. The aim of this study is to evaluate the susceptibility for mass movement within the Xiangxi River backwater area using geographic information system （GIS）. We used existing mass movements and the conditioning factors （geology, elevation, slope, curvature, land use, and land use change） for analyzing mass movement susceptibility. Mass movements and geology were mapped in the field to establish a mass movement inventory and a geological map. Land use and digital elevation model （DEM） were obtained from remote-sensing data. We determined the relation between mass movements and the conditioning factors by using the frequency ratio method and found strong relation between mass movements and both natural and human-influenced conditioning factors.

关键词： mass movement susceptibility GIS frequency ratio Xiangxi catchment Three Gorges Reservoir.

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FerryBox: Using Automated Water Measurement Systems to Monitor Water Quality: Perspectives for the Yangtze River and Three Gorges Dam

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Journal of Earth Science 2010年第6期21卷 861-869页

作者： Carsten Frank Friedhelm Schroeder Wilhelm Petersen Helmholtz-Zentrum Geesthacht GmbH Institute for Coastal Research

The building of the Three Gorges Dam （Hubei （湖北） Province, China） has transformed a region with an economy based on sustainable agriculture for millennia into an entirely different environment within an exceptionally short time. This disrupts the natural biogeochemieal cycles of carbon, nutrients, and metals and possibly will affect the whole catchment including downstream ecosystems, such as wetlands, estuaries, deltas, and adjacent sea areas. Starting from changes that have already been documented, this article concentrates on the possible use of a ＂FerryBox＂, which is an automated water quality measurement system on board a ship or on shore, to monitor the short and long term development of the quality of the river water in the backwater area and downstream of the dam. While there are already research programmes running to monitor the water quality of the river and the backwater area, these programs are limited to ship campaigns with sampling and laboratory analysis. The spatial and temporal resolution of such measurements is not sufficient for an overall assessment of the water quality and for prognoses in the context of anthropogenic and climate change. Therefore, a concept of applying regular automated observations by a FerryBox is presented. It is shown that such systems are very well suited to give feedback for the assessment of measures to improve the water quality.

关键词： Three Gorges Dam Yangtze River eutrophication FerryBox.

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Evaluating the Validity of a Nitrate Quick Test in Different Chinese Soils

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Pedosphere 2012年第5期22卷 623-630页

作者： YUE Xian-Lu LI Fei HU Yun-Cai ZHANG Huai-Zhi JI Hong-Jie ZHANG Wei-Li U. SCHMIDHALTER Chair of Plant Nutrition Technische Univcrsitiit Miinchen Emil-Ramann-Str. 2 Freising D-85350 (Germany) Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 (China)

Because laboratory tests are expensive and time-consuming and may not be available to farmers, soil nitrate quick tests are required for optimal nitrogen management strategies in China to increase nitrogen use efficiency and to reduce nitrogen losses. A total of 328 soil samples were collected at different soil depths from 225 sites in China, which covered a wide range of climatic and geographic regions, soil types, croplands and soil textures, to evaluate the suitability of a quick reflectometer test method for analysing soil NO3-N in a wide range of soil NO3 concentrations, soil types and cropping systems in China, mainly by comparison of soil NO3-N assessed by a quick-test method （a reflectometer） and a standard laboratory method, i.e., high-performance liquid chromatography （HPLC）. The reflectometer showed excellent agreement with the laboratory HPLC method with regard to soil nitrate contents for all analysed soil samples. The linear regression had slopes of 1 ± 0.08 and intercepts of ± 1.38 mg NO（-,3）-N L^（-1） among different soil types and croplands. Compared with the 1：1 lines, the regression analysis for each soil type showed statistically significant but small differences in slope; the relative difference between the values measured using the two analytical systems varied from -8% to 6%, and there were no differences in intercept except for paddy soil. The reflectometer showed adequate, statistically significant precision in determining soil nitrate contents, and it could therefore be directly used instead of the laboratory methods for soil NO（-,3）-N measurement in China.

关键词： dilution N recommendation nitrate test strip reflectometer , soil NO(3,-)-N

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