检索结果-南通市图书馆

Journal of Mountain Science 2020年第12期17卷 2929-2941页

作者： ZHANG Ting-yu MAO Zhong-an WANG Tao Shaanxi provincial land Engineering Construction Group land Survey planning and Design institute Co. Ltd.Xi'an710075China

landslide susceptibility mapping is significant for landslide *** approaches have been used for landslide susceptibility prediction,however,their performances are *** study constructed a hybrid model,namely box counting dimension-based kernel logistic regression model,which uses fractal dimension calculated by box counting method as input data based on grid cells mapping unit and terrain mapping *** performance of this model was evaluated in the application in Zhidan County,Shaanxi Province,***,a total of 221 landslides were identified and mapped,and 11 landslide predisposing factors were ***,the landslide susceptibility maps(LSMs) of the study area were obtained by constructing the model on two different mapping ***,the results were evaluated with five statistical indexes,sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV) and *** statistical indexes of the model obtained on the terrain mapping unit were larger than those based on grid cells mapping *** training and validation datasets,the area under the receiver operating characteristic curve(AUC) of the model based on terrain mapping unit were 0.9374 and 0.9527,respectively,indicating that establishing this model on the terrain mapping unit was advantageous in the study *** results show that the fractal dimension improves the prediction ability of the kernel logistic *** addition,the terrain mapping unit is a more promising mapping unit in Loess areas.

关键词： Kernel logistic regression model landslide susceptibility GIS Fractal dimension

land Use Changes of an Aeolian-Loessial Soil Area in Northwest China: Implications for Ecological Restoration

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第3期19卷 356-361页

作者： CHEN Yu-Fu LIU Yan-Sui WANG Jing YAN Jian-Ping GUO Xu-Dong institute of Geographic Sciences and Natural resources Research Chinese Academy of Sciences Beijing 100101 China） Key Laboratory of land Use Institute of Land Surveying ~ Planning Ministry of Land ＆ Resources Beijing 100035（China）

China has experienced dramatic land use changes over recent decades, with marked environmental and socio-economic consequences. Hengshan County, located in the aeolian-loessial area of Northwest China, was investigated to illustrate land use changes and their implications for environmental and long-term rural economic development. The farmland in Hengshan County significantly decreased during 1990–2003, whereas forest land and grassland increased. The conversion rates of farmland, orchard land, forest land and construction land varied markedly among different periods: 1990–1995, 1995–2000 and 2000–2003. Conversion of orchard land, grassland and construction land was dominant in 1990–1995, whereas the conversion of farmland to forest land mainly occurred in 2000–2003. The results suggested a profound transition in institutional policy and political economy of land management, including implementation of integrated soil erosion control projects, adoption of a market-oriented economy and the ‘Grain-for-Green’ policy, during this period in China. To achieve long-term sustainable land use in Hengshan County, efforts should aim at increasing off-farm income of rural families as well as establishing land-economizing mechanisms to promote land productivity, in addition to conservation measures.

关键词： Hengshan County land management per capita land area policy sustainable land use

Urban vacant land in growing urbanization:An international review

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2020年第4期30卷 669-687页

作者： SONG Xiaoqing WEN Mengmeng SHEN Yajing FENG Qi XIANG Jingwei ZHANG Weina ZHAO Guosong WU Zhifeng Research Center for Spatial planning and Human-Environment System Simulation School of Geography and Information EngineeringChina University of GeosciencesWuhan 430074China hunan Key Laboratory of land resources Evaluation and Utilization Hunan Planning Institute of Land and ResourcesChangsha 410007China School of Public Administration China University of GeosciencesWuhan 430074China School of Geographical Sciences Guangzhou UniversityGuangzhou 510006China

Urban growth and shrinkage constitute the overall pattern of growing urbanization across the *** on urban vacant land(UVL)are few,and have proved to be mainly rudimentary and *** paper first presents the definition of UVL based on bibliometric ***,morphology,proximate causes,and the multiple functions of UVL are then analyzed at parcel,transect,city,and national levels based on an international *** show that UVL can be categorized by land cover,land usage,and land ***,UVL has been widespread and *** example,the occurrence probabilities of UVL in the cases of Guangzhou and New York are 8.46%-8.88%and 3.17%-5.08%,*** average vacancy rate of residential land amounts to 11.48%in 65 ***,UVL shows fragmentation and irregular shape,and significant spatial differences exist at parcel,transect,city,and national *** causes,such as excessive land division,irregularly shaped land parcels,decreases in resident population,deindustrialization,land speculation,insufficient investment,and environmental concerns,can all result in ***,UVL has become a gray area of social,economic,and ecological ***,it can also be considered a potential resource for enhancing urban *** implications to promote urban sustainability using monitoring,control,and differential revitalization of UVL are presented.

关键词： urban vacant land urbanization shrinking cities land use transition

Dynamic Evolvement of Agricultural System and Typical Patterns of Modern Agriculture in Coastal China:A Case of Suzhou

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2009年第3期19卷 249-257页

作者： ZHAI Rongxin LIU Yansui institute of Geographic Sciences and Natural resources Research Chinese Academy of Sciences Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Shandong provincial land Survey ＆ planning institute Jinan 250014 China

Based on dynamic theory of system, agriculture is a complex system composed by element, structure, function and development. Firstly, this paper analyzes their connotation and relationship, which could be simply described that in virtue of element integrating and structure optimizing, agricultural system may achieve multifunctionality to meet increasingly diverse demands. As a case study of Suzhou, it concludes that Suzhou has a LP-dependence on agricultural element, and the growth extent of agricultural productivity correlates to the ratio of agricultural labor reduc- ing rate to farmland reducing rate. Agricultural structure of Suzhou changed with time, and in the early 1980s and 2000s it was most notable. Correspondingly, agricultural function has experienced a succession process: 'production', 'production-living', and 'production-living-ecology'. At last, based on questionnaires and interviews, some new characteristics and problems of agricultural development in coastal developed region of China have been put forward. Meanwhile, some typical patterns of modern agriculture in Suzhou which adapt to system evolving are also brought up such as export-oriented agriculture, enterprises-leading agriculture, agricultural science and technology parks, characteristic and stereoscopic agriculture, tourism and sightseeing agriculture.

关键词： modern agriculture agricultural system Suzhou coastal China

Effects of water and nitrogen conditions under surge-root irrigation on growth and yield of apple trees

在线全文

学校读者我要写书评

暂无评论

排灌机械工程学报 2023年第2期41卷 179-186页

作者： YIN Yongle FEI Liangjun LI Zhe LIU Teng LI Zhongjie HAO Kun PENG Youliang institute of Water resources and Hydroelectric Engineering Xi′an University of TechnologyXi′anShaanxi 710048China Shaanxi provincial land Engineering Construction Group Land Survey Planning and Design InstituteXi′anShaanxi 710064China Rural Revitalization planning and Development Guidance Center of Yulin YulinShaanxi 719000China

In order to explore the effects of different irrigation and nitrogen application on growth cha-racteristics and yield of apple trees under surge-root irrigation in mountainous areas of northern Shaanxi, field experiments were carried out with different apple trees. Three irrigation levels were applied: 85%-100%(H1), 70%-85%(H2) and 55%-70%(H3) of the field water capacity, respectively, and three nitrogen levels were N1(360 g/plant), N2(240 g/plant) and N3(120 g/plant). The results show that irrigation and nitrogen application has significant effects on new shoot length, flowering and fruit setting, fruit diameter, fruit volume and yield of apple. The leaf area index(LAI) shows a single trend during the growth period, and the peak value appears in the middle of July. Under the same irrigation level, compared with N3, N1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 17.91%, 28.31%, 18.75%, 11.38%, 10.13%, 36.60%, 20.92% and 5.19%, respectively, while N2 also increases by 12.40%, 15.63%, 4.86%, 5.40%, 5.11%, 17.01%, 26.17% and 13.74%, respectively. The rate of flowering and fruit setting decreases with the increase of nitrogen application. Under the same nitrogen level, compared with H3, H1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 34.65%, 15.49%, 30.77%, 3.93%, 4.95%, 12.86%, 33.15% and 28.62%, respectively, while H2 also increases by 33.67%, 16.42%, 67.52%, 3.81%, 2.97%, 11.57%, 43.45% and 27.26%, respectively. The rate of flowering and fruit setting decreases first and then increases with the increase of irrigation amount. Compared with H3N3, the yield of other treatments increases by 2.69%-52.20%, while H2N1 treatment has the highest yield(26 852.55 kg/ha). Considering from the point of view of promoting growth and increasing yield, the best water and nitrogen combination mode of mountain apple in northe

关键词： mountain apple surge-root irrigation irrigation nitrogen growth yield

同方期刊数据库

Spatial analysis of land use change effect on soil organic carbon stocks in the eastern regions of China between 1980 and 2000

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2017年第3期8卷 597-604页

作者： Xueqi Xia Zhongfang Yang Yuan Xue Xin Shao Tao Yu Qingye Hou School of Earth Sciences and resources China University of Geosciences Beijing 100083 China Chongqing institute of land Surveying and planning Chongqing 404000 China

Spatial distributions of 0-20 cm soil carbon sources/sinks caused by land use changes from the year 1980 to 2000 in an area of 2.97 ~ 106 km2 in eastern China were investigated using a land use dataset from a recent soil geochemical survey. A map of soil carbon sourcesJsinks has been prepared based on a spatial analysis scheme with GIg. Spatial statistics showed that land use changes had caused 30.7 ＋ 13.64 Tg of surface soil organic carbon loss, which accounts for 0.33% of the total carbon storage of 9.22 Pg. The net effect of the carbon source was estimated to be ~ 71.49 Tg soil carbon decrease and ~ 40.80 Tg increase. land use changes in Northeast China （NE） have the largest impact on soil organic carbon storage compared with other regions. Paddy fields, which were mainly transformed into dry farmland in NE, and constructed land in other regions, were the largest carbon sources among the land use types. Swamp land in NE was also another large soil carbon source when it was transformed into dry farmland or paddy fields. Dry farmland in the NE region formed the largest soil organic carbon sink, as some were trans- formed into paddy fields, forested land, and other land use types with high SOCD.

关键词： land use change Soil organic carbon GIS Eastern China

Water and salt movement in different soil textures under various negative irrigating pressures

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2016年第8期15卷 1874-1882页

作者： WANG Jia-jia HUANG Yuan-fang LONG Huai-yu Department of Soil and Water Sciences College of Resources and Environmental Sciences China Agricultural University/Key Laboratory of Arable Land Conservation (North China) Minstry of Agriculture/Key Laboratory of Agricultural Land Quality Monitoring Ministry of Land and Resources institute of Agricultural resources and Regional planning Chinese Academy of Agricultural Sciences

supported by the National High-Tech R＆D Program of China （2013AA102901）

关键词： negative pressure irrigation volumetric water content soil salt content soil texture

En-route headway-based bus reliability with real-time data at network scale

在线全文

学校读者我要写书评

暂无评论

Transportation Safety and Environment 2020年第3期2卷 236-245页

作者： Yiyi Li Huadong Tan hunan Communications Research institute 472 Furong North RoadChangsha410074China hunan provincial Communications planning Survey&Design Institute598 Moon Island RoadChangsha410200China

Bus reliability has long attracted attention and been extensively studied to enhance service ***,existing research generally evaluates bus reliability of specific routes or *** this end,this study explores en-route bus reliability with real-time data at network *** on data of bus automatic vehicle location and smart card usage in Ningbo,China,this study calculates headway-based reliability with the difference between actual and scheduled headway at each *** demonstrate the trend of stop-level reliability along a bus route,reliability is graded and visualized on a map with ridership at each stop,which is then weighted with passenger-boarding ***-level reliability is then quantified and mapped,where unreliable service basically concentrates in or extends through the centre *** respect to network-level reliability,temporal changes are demonstrated with ridership on weekdays and at the *** is observed that on weekdays,the reliability trend is similar to that of ridership,implying a causal relationship between bus travel-time variation and bus waiting-time at ***,a reliability comparison between weekdays in December and October shows the necessity of evaluating periodically and around important events to avoid negative riding experiences that discourage public transport *** research provides insights for bus agencies to systematically evaluate service reliability both spatially and temporarily,in order to identify and prioritize the routes and stops where the scope for reliability improvement and the expected benefit are greatest.

关键词： bus reliability real-time data at network scale multi-level evaluation visualization

Spatial distribution prediction and benefits assessment of green manure in the Pinggu District,Beijing,based on the CLUE-S model

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2016年第2期15卷 465-474页

作者： ZHANG Li-ping ZHANG Shi-wen ZHOU Zhi-ming HOU Sen HUANG Yuan-fang CAO Wei-dong College of resources and Environment China Agricultural University/Key Laboratory of Arable Land Conservation(North China)Minstry of Agriculture/Key Laboratory of Agricultural Land Quality MonitoringMinistry of Land and Resources School of Earth and Environment Anhui University of Science and Technology institute of Agricultural resources and Regional planning Chinese Academy of Agricultural Sciences

Green manure use in China has declined rapidly since the 1980 s with the extensive use of chemical *** deterioration of field environments and the demand for green agricultural products have resulted in more attention to green *** intervention and policy-oriented behaviors likely have large impacts on promoting green manure ***,little information is available regarding on where,at what rates,and in which ways（i.e.,intercropping green manure in orchards or rotating green manure in cropland） to develop green manure and what benefits could be gained by incorporating green manure in fields at the county *** paper presents the conversion of land use and its effects at small region extent（CLUE-S） model,which is specifically developed for the simulation of land use changes originally,to predict spatial distribution of green manure in cropland and orchards in 2020 in Pinggu District located in Beijing,*** types of land use for planting or not planting green manure were classified and the future land use dynamics（mainly croplands and orchards） were considered in the *** scenarios were used to predict the spatial distribution of green manure based on data from 2011：The promotion of green manure planting in orchards（scenario 1） and the promotion of simultaneous green manure planting in orchards and croplands（scenario 2）.The predictions were generally accurate based on the receiver operating characteristic（ROC） and Kappa indices,which validated the effectiveness of the CLUE-S model in the *** addition,the spatial distribution of the green manure was acquired,which indicated that green manure mainly located in the orchards of the middle and southern regions of Dahuashan,the western and southern regions of Wangxinzhuang,the middle region of Shandongzhuang,the eastern region of Pinggu and the middle region of Xiagezhuang under scenario *** manure planting under scenario 2 occurred in orchards in the middle re

关键词： CLUE-S model green manure spatial distribution prediction benefits assessment

Dynamic Modeling Framework of Sediment Trapped by Check-Dam Networks:A Case Study of a Typical Watershed on the Chinese Loess Plateau

在线全文

学校读者我要写书评

暂无评论

Engineering 2023年第8期27卷 209-221页

作者： Pengcheng Sun Yiping Wu Key Laboratory of Degraded and Unused land Consolidation Engineering the Ministry of Natural ResourcesShaanxi Provincial Land Engineering Construction Group Co.Ltd.Xi’an 710075China Key Laboratory of Soil and Water Conservation on the Loess Plateau of Ministry of Water resources Yellow River Institute of Hydraulic ResearchZhengzhou 450003China Technology Innovation Center for land Engineering and Human Settlement Shaanxi Provincial Land Engineering Construction Group Co.Ltd.&Xi’an Jiaotong UniversityXi’an 710115China

Check-dam construction is an effective and widely used method for sediment trapping in the Yellow River Basin and other places over the world that are prone to severe soil *** estimations of the dynamic sediment trapped by check dams are necessary for evaluating the effects of check dams and planning the construction of new *** this study,we propose a new framework,named soil and water assessment tool(SWAT)–dynamic check dam(DCDam),for modeling the sediment trapped by check dams dynamically,by integrating the widely utilized SWAT model and a newly developed module called *** then applied this framework to a typical loess watershed,the Yan River Basin,to assess the time-varying effects of check-dam networks over the past 60 years(1957–2016).The DCDam module generated a specific check-dam network to conceptualize the complex connections at each time step(monthly).In addition,the streamflow and sediment load simulated by using the SWAT model were employed to force the sediment routing in the check-dam *** evaluation results revealed that the SWAT-DCDam framework performed satisfactorily,with an overestimation of 11.50%,in simulating sediment trapped by check dams,when compared with a field survey of the accumulated sediment *** the Yan River Basin,our results indicated that the designed structural parameters of check dams have evolved over the past 60 years,with higher dams(37.14%and 9.22%increase for large dams and medium dams,respectively)but smaller controlled areas(46.03%and 10.56%decrease for large dams and medium dams,respectively)in recent *** retained by check dams contributed to approximately 15.00%of the total sediment load reduction in the Yan River during 1970–***,our developed framework can be a promising tool for evaluating check-dam effects,and this study can provide valuable information and support to decision-making for soil and water conservation and check-dam planning and management.

关键词： Check dams Dynamic check dam(DCDam) Loess Plateau Sediment trapping SWAT