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Table of Content

    20 December 2011, Volume 26 Issue 12 Previous Issue    Next Issue
    Resources Utilization and Management
    Spatial Analysis on the Contribution of Industrial Structure Change to Regional Energy Efficiency—A Case Study of 31 Provinces in Mainland China
    LIU Jia-jun, DONG Suo-cheng, LI Yu
    2011, 26 (12):  1999-2011.  doi: 10.11849/zrzyxb.2011.12.001
    Abstract ( )   PDF (550KB) ( )   Save
    Energy is an important production factor. With more energy put into production activities, labor productivity has been increased greatly, which promoted economic and social development in consequence. Industrial structure change is an important factor which affects growth of regional energy efficiency. In modern economic development, industrial structure improvement is closely related to regional energy efficiency and the status of industrial structure and energy efficiency can together reflect one country's development level, sustainable development ability and the direction in which its economy will be heading. This paper aims to discuss the contribution of industrial structure fluctuating to regional energy efficiency growing in spatial perspective. Based on 31 mainland provinces in China, using the statistics of industrial structure and corresponding energy utilized data, adopting mathematic model and spatial analysis approaches, it is found that 31 provinces differed in contribution of industrial structure fluctuating to regional energy efficiency growing. The outcome reflected contribution is obvious in those provinces with appropriate industrial structure and good economic basis and the ones developed late as well as the undeveloped middle and western provinces which were in initial stage of industrial restructuring, but that is obscure in those provinces which have not developed leading industries with weak economic basis as well as the ones with relatively fitting low end industrial structure.
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    The Hypothesis and Verification of Urban Sacrificial and Wasted Sprawl —A Case Study in Xuzhou
    LI Xiao-shun, QU Fu-tian, ZHANG Shao-liang, GONG Yun-long
    2011, 26 (12):  2012-2024.  doi: 10.11849/zrzyxb.2011.12.002
    Abstract ( )   PDF (810KB) ( )   Save
    Urban sprawl is a complex problem in national sustainable development and has aroused public concern. Three sticking points are identified as to break the "reasonable limits", approach to "survival red line" and surpass "harmonious theme". Put the "three lines" as the starting point and put forward sacrificial and wasted urban sprawl hypothesis from the perspective of land price equilibrium, this paper conducts an empirical analysis by taking Xuzhou city as an example. First, the results of the theoretical analysis showed that different from foreign countries' welfare-gain sprawl and welfare-loss sprawl, urban sprawl in China can be divided into two types of sacrificial and wasted sprawl, and there are also three boundaries, namely ideal-boundary, moderate-boundary and limit-boundary. Second, the evaluation results show that, the comprehensive value of agricultural resources is 9.58×106yuan/hm2, the market value is 5.93×106yuan/hm2, the non-market value (the sum of the ecological and social value) accounts for only 38.07%. Third, from the empirical analysis, the scale of sacrificial sprawl is 1.08×104 hm2, of which farmland occupation is 4.32×103 hm2. The scale of wasted sprawl is 2.83×103 hm2, of which farmland occupation is 8.81×102 hm2. Based on the research conclusions, this article suggests that a two-step adjustment in urban governance and land policy should be formulated in the future. The first step is to change economic development way and government performance appraisal system and effectively check wasted urban sprawl caused by government failure through adjusting moderate-boundary and strengthening basic farmland and other key resources protection. The second step is to improve land market mechanism as soon as possible and to turn agricultural land external cost into internal one. And they can be taken as main basis for decision-making in urban sprawl governance.
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    Implementation Strategies of Land Consolidation in Chongqing Based on the Ideas of "Decreasing Pressure, Increasing Efficiency"
    LI Xia, SHAO Jing-an, XIE De-ti
    2011, 26 (12):  2025-2038.  doi: 10.11849/zrzyxb.2011.12.003
    Abstract ( )   PDF (892KB) ( )   Save
    Using the conditions of land consolidation, such as its planning scales, increasing areas, investments and effective operations, especially the demands of future economic development for land use patterns, this paper obtains the implementation strategies of land consolidation and its operation in Chongqing, based on the ideas of "decreasing pressure, increasing efficiency". The results showed that the implementation strategies of future land consolidation for "decreasing pressure, increasing efficiency" would focus on cultivated land consolidation, in associating with the potential unit of residential land consolidation in Chongqing. However, over-rely on the development of land consolidation was not in line with the objective reality of Chongqing. The policy inclinations of the state to Chongqing, as the building of new countryside, the transfer of collective land-use right and the pilot area of coordinating urban and rural development, play the highlight role on the implementation strategies of land consolidation. The implementation strategies of growth-promoting cooperation combine the right replacement of government to land consolidation. In this mode, the government leads no longer just the operation of regional land consolidation, while provides a relaxed environment for its operation. Thus, the maximum social resources are used to participate in regional land consolidation, such as main private and on-governmental organizations, including companies, enterprises and individuals, and so on. The objective of "decreasing pressure, increasing efficiency" is paid more attention in the metropolitan area, where old city regeneration and annexation of villages into a larger settlement are carried out. Increasing efficiency is focused on western Chongqing, where increasing the coefficient of cultivated land is emphasized, and in the valley and ridge paralleling northern bank of the Yangtze River of the Three-Gorges Reservoir area, where the increase the output of cultivated land is more interesting for land consolidation. However, in the northeastern and southeastern Chongqing and southern bank of the Yangtze River of the Three-Gorges Reservoir area, decreasing pressure is mainly implemented, in order to increase the distribution of forest areas. Four areas the above-mentioned become the spatial dependence patterns of Chongqing's land consolidation under the new "implementation strategies". Restoring and reconstructing landscape patterns is emphasized mainly in the metropolitan area, northeastern and southeastern Chongqing and southern bank of the Yangtze River of Three-Gorges Reservoir area, while restoring mode is focused primarily on western Chongqing and northern bank of the Yangtze River of Three-Gorges Reservoir area. At the same time, biological fences for every area are built to protect its vegetation naturally recovering. Moreover, ecological flow among single islands/valley and ridge paralleling, or between them are being together through the corridors. Consequently, the conception of natural-artificial ecological experiment economic area is achieved. Our findings contribute to the demand for land and the transfer of economic gradient of economic "great-leap-forward" development of Chengdu-Chongqing pilot area. The understanding and awareness is richened in land consolidation and regional development at the national level.
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    Resources Safety
    Model for Risk Analysis between Supply and Demand of Water Resources Based on Logistic Regression and NFCA and Its Application
    QIAN Long-xia, WANG Hong-rui, JIANG Guo-rong, YU Song
    2011, 26 (12):  2039-2049.  doi: 10.11849/zrzyxb.2011.12.004
    Abstract ( )   PDF (581KB) ( )   Save
    In the studies of water resources supply and demand, supply and demand balance has received much more attention, but risk between supply and demand is little addressed. In this paper, the index system of risk between supply and demand is established from the viewpoint of threat, exposure and vulnerability. Based on logistic regression and nonlinear fuzzy comprehensive assessment, a model for risk analysis is developed. Considering the randomness of water supply, taking Beijing for example, risks under many different inflow conditions are studied. The results show that, all the inherent risks in 2020 are first grade in the inflow conditions of 1956 to 2007. After taking measures of reclaimed water reuse and South-to-North Water Transfer, the third grade and fourth grade risks accounts for 75%, with 25% of first grade and second grade risk. Therefore, risks are still high in the case of little precipitation.
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    Design of Weather Index Insurance Contact for Tea Frost
    LOU Wei-ping, JI Zong-wei, QIU Xin-fa, WU Li-hong, HE Xiao-xiao
    2011, 26 (12):  2050-2060.  doi: 10.11849/zrzyxb.2011.12.005
    Abstract ( )   PDF (370KB) ( )   Save
    This paper takes tea production in Xinchang County of Zhejiang as an example, under the principle of disaster risk analysis and requirement for agricultural insurance, combined with characteristics such as huge topographic relief and significant difference in microclimate in southern mountain area of China, carries out risk evaluation and agricultural insurance product design through elaborating frost disaster which affected tea production in March at village & township level. Firstly, the paper confirms tea's economic output changes from time to time in productive life based on tea's daily economic output in normal years of tea planting base; combined with economic loss rate due to frost during/before productive life in previous years to confirm frost weather index—minimum temperature in a period before productive life or after productive life, different minimum temperature is in accordance with tea's economic loss rate. Support Vector Machine (SVM) is used to extend mesoscale automatic weather station's minimum temperature data to 30 years in specific to non-linear relation existing among meteorological data of mesoscale automatic weather station in villages, towns and county; minimum temperature corresponds to tea's economic loss rate, therefore it's possible to calculate different levels of frost risk based on minimum temperature data and confirm tea's economic loss risk, and to solve problems such as tea's short planting period, short accumulation period for mesoscale automatic weather stations and unable to meet risk analysis requirement. There're certain differences between risk results calculated on different risk analysis models. The article applies probability density function fitting distributions such as Beta, Exponential, Gumbel, Gamma, Generalized Extreme Value, Inverse Gaussian, Logistic, Log-Logistic, Lognormal, Lognormal2, Normal, Pareto, Pareto2, Pearson Type V, Pearson Type VI, Student, Weibull to minimum temperature data sequence in every township and street in the study area. Parameter estimation in distribution model applies maximum likelihood method, both of Anderson-Darling and Kolmogorov-Smirnov examination selected from different production periods in different townships and villages passed significance level of 0.05. Almost coincidence distribution of P-P drawing's tailer and diagonal line confirms that Generalized Extreme Value distribution's risk probability estimation as the best theoretical probability distribution function, thus being relatively stable with realistic risk evaluation result. On the basis of quantitative risk analysis and considering actual needs of policy-based agricultural insurance operation, combined with advantages of regional output insurance and weather index, the paper designs tea's frost weather index insurance. It is to confirm insurance rate and compensation agreement in a pre-designated area on the basis of frost caused economic loss rate and occurrence risk in the case that frost happens during tea's production life. Tea's frost weather index is weather index corresponds to pre-determined frost meteorological event, every index value corresponds with certain tea economic loss rate and claim ratio. This paper suggests to carry out compensation according to frost weather index confirmed by meteorological data observed by mesoscale automatic weather stations in every township, village and street, compensation index for rural household and insurance company is measured by representative weather stations closest to rural households, therefore basis risks, adverse selection and moral risk are reduced. And there is no need to use huge human and non-human sources to inspect and judge losses in claim settlement after disaster, and the claim settlement efficiency is high but the claim settlement cost is low, hence this is a positive and effective technological measure to carry out tea insurance and promote sustainable development of agricultural insurance.
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    Resources Ecology
    Estimation of the Net Ecosystem Productivity in Huang-Huai Hai Region Combining with Biome-BGC Model and Remote Sensing Data
    HU Bo, SUN Rui, CHEN Yong-jun, FENG Li-chao, SUN Liang
    2011, 26 (12):  2061-2071.  doi: 10.11849/zrzyxb.2011.12.006
    Abstract ( )   PDF (711KB) ( )   Save
    As two key variables to represent vegetation activities, the Net Ecosystem Production(NEP) and the Net Primary Productivity(NPP)played important roles in the study of global change and regional ecological environment evaluation. Biome-BGC was a biogeochemical cycles model, which could simulate the storage and fluxes of water, carbon and nitrogen within the vegetation and soil components of a terrestrial ecosystem. In this paper, in use of the series of MODIS LAI product and the meteorological data in 2004, we simulated the NEP and NPP in the Huang-Huai-Hai Region. Since there was no crop eco-physiological parameters in the Biome-BGC model, we simulated the crop by modifying the grass eco-physiological parameters, and adding the code of fertilizers, irrigation and harvest.The simulated results showed that the NEP and NPP were greater in the southern part of the region.The respective order of average NEP and NPP of different vegetation types was as follows: mixed forest, deciduous broadleaf forest, evergreen needleleaf forest, crop, shrub and grassland; and mixed forest, crop,deciduous broadleaf forest, evergreen needleleaf forest, shrub and grassland.Compared to the observation data, MODIS NPP product and the statistical data, we found that Biome-BGC model successfully simulated the regional vegetation productivity, and the coefficient of determination between the simulated NPP of crop and the statistical data had reached 0.6123. In addition, the simulated result of crop NPP in the Huang-Huai-Hai Region was closer to the statistical data than the MODIS NPP product.
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    The Variation Characteristics of Soil Organic Carbon of Typical Alpine Slope Grasslands and Its Influencing Factors in the "Three-River Headwaters" Region
    SUN Wen-yi, SHAO Quan-qin, LIU Ji-yuan, XIAO Tong
    2011, 26 (12):  2072-2087.  doi: 10.11849/zrzyxb.2011.12.007
    Abstract ( )   PDF (808KB) ( )   Save
    Exploring the distribution characteristics of soil organic carbon and its influencing factors under different degraded types of alpine slope grasslands was crucial to better understand the changes of soil organic carbon content and responses to global climate change. Two types of alpine grassland (alpine meadow and alpine steppe), and the impact mechanism of soil organic carbon were studied under the influences of external environment, such as water erosion, wind erosion, freezing-thawing erosion and rodent damage in the "Three-River Headwaters" region. The results showed that: the contents of soil organic carbon of alpine meadow dominated by Kobresia pygmaea and Kobresia humilis were higher than alpine steppe dominated by Stipa purpurea Griseb. Under the conditions of the lightly degraded and water erosion, the average content of alpine meadow QMH1 was 2.2 times (P<0.01) of alpine steppe QMH2 which was 3.5 km away from QMH1. And it was similar to the conditions of the lightly degraded and wind erosion, the average content of alpine meadow WDL was 3.8 times (P<0.01) of alpine steppe BDQ. Under the influence of water erosion, the soil organic carbon of alpine grassland was transferred downward along the slope grassland. The soil organic carbon content of lower slope (downward 580 m distance from the top slope ) of alpine meadow ML1 was 22% higher (P<0.05)than the upper slope (upward 580 m distance from the top slope). The overlying distribution characteristics of soil organic carbon for ML2 alpine meadow was performed, not only decreased with the increase of degradation, but also migrated downward along the slope grassland due to water erosion. The soil organic carbon content of extremely degraded grassland, located on the lower slope compared with severely degraded grassland, was 49.3% (P<0.05) higher than severely degraded grassland for ML2 alpine meadow. Wind erosion made rough the soil surface of grassland and accelerated mineralization of soil organic carbon. The average content of soil organic carbon of ELH lightly impacted by lake breeze was 27.9% higher than ZLH (P<0.05) strongly impacted by lake breeze. The soil organic carbon content was reduced by freeze-thaw erosion, but the difference was not significant. Rodent damage not only reduced the content of soil organic carbon, but also accelerated deterioration of grassland, the average content of soil organic carbon of moderate degradation SDⅠ-Ⅲ around the rat holes were 2.1 time of the extremely degraded grassland SDⅣ-Ⅵ; and the average content of soil organic carbon of the moderately degraded grassland ML2Ⅰ-Ⅱ away from rat holes was 1.6 times of the extremely degraded grassland ML2Ⅳ-Ⅵ. The soil organic carbon of alpine slope grassland was aggravated due to influence by wind erosion, water erosion, freeze-thaw and rodent damage.
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    Study on Climatic Division of Natural Grassland in Inner Mongolia
    LIU Hong, GUO Wen-li, ZHENG Xiu-qin
    2011, 26 (12):  2088-2099.  doi: 10.11849/zrzyxb.2011.12.008
    Abstract ( )   PDF (611KB) ( )   Save
    According to the records from 107 meteorological stations in Inner Mongolia, using the Gradient Inverse Square Formula, the grid data in Inner Mongolia were calculated by interpolating under the GIS environment,and the resolution of grid data was 1 km×1 km in combination with the distribution characteristics of the grassland types and animal production structure in Inner Mongolia. The climatic regionalization indicators in Inner Mongolia are defined, which include five grassland types, six grassland yields grades and geographical distribution of five major grazing livestock. Using these climatic regionalization indicators, the climate data grades of each grid are classified, the regionalization thematic maps of grassland types, grassland yields grades and major grazing livestock in Inner Mongolia were drawn. Each kind of the regions was remarked, and suggestions for sustainable development were proposed. This study could provide scientific basis for the adjustment of agricultural structure and the optimal distribution of animal husbandry in Inner Mongolia grassland.
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    Review of Water Conservation Value Evaluation Methods of Forest and Case Study
    SI Jin, HAN Peng, ZHAO Chun-long
    2011, 26 (12):  2100-2109.  doi: 10.11849/zrzyxb.2011.12.009
    Abstract ( )   PDF (511KB) ( )   Save
    In terms of various understanding of water conservation value of forests and dramatic differences with outcomes from different methods, the conceptions of methods have been analyzed based on the summary of methods. Comprehensive Water Storage Ability Method, Precipitation Storage Method, Water Balance Method and Equivalence Method have been chosen to be applied to Zhifanggou watershed and Nihegou watershed of the Loess Plateau in northern China and Nüerzhai watershed in southern China. It was shown that the results of different methods were inconsistent because of the difference of connotations of these methods. The difference between methods was significant especially in the two small watersheds in the Loess Plateau. For Zhifanggou watershed, the results from Comprehensive Water Storage Ability Method and Equivalence Method were higher, while the results from Water Balance Method I and Precipitation Storage Method were lower, with the range of the four methods being around 1.5 million. In contrast, the results in Nüerzhai watershed had no significant differences from each other. The range of the results from the methods above can be around 0.2 million. But the result from Water Balance Method Ⅱ has been shown abnormal in all watersheds studied. Further analysis showed that Comprehensive Water Storage Ability Method and Equivalence Method aim at the potential ability of water storage, while Precipitation Storage Method I and Water Balance Method I focus on the actual ability of water storage. In arid and semi-arid areas, the result by Comprehensive Water Storage Ability Method is higher than the actual value, but smaller in humid areas, just because that the actual ability of water storage is often lacking in arid and semi-arid areas. Besides, the equivalent factors used in Equivalence Method should be modified according to the climate in the study area in order to cater to the actual situation of different studied areas. Moreover, the calculation formulation of Water Balance Method Ⅱ is inconsistent with the connotation supposed to reflect. That's the reason why the result of Water Balance Method Ⅱ is rather lower, sometimes even negative. Thus, Water Balance Method Ⅱ was not suggested to be used in the evaluation of water conservation value. The method of water storage ability by soil, which has similar connotation to Water Balance Method Ⅱ, could be considered as an alternative way.
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    Resources Evaluation
    Change of Flood Disasters in China since the 1880s and Some Possible Causes
    CHEN Ying, YIN Yi-xing, CHEN Xing-wei
    2011, 26 (12):  2110-2120.  doi: 10.11849/zrzyxb.2011.12.010
    Abstract ( )   PDF (543KB) ( )   Save
    Based on the flood data of China and annual precipitation data of eastern China since 1880, the paper discusses the change characteristics of flood disasters in China, and its relationship with precipitation change and human activities. The adopted methods include Mann-Kendall (MK) test, empirical mode decomposition (EMD) and correlation analysis. The results are as follows: 1) the magnification of flood disaster occurred in the late 19th century, the period during 1950s and 1960s, and the late 20th century. The magnification periods of flood disasters in the late 19th century and during 1950s and 1960s corresponded well with the wet periods, while the flood magnification period occurring in the late 20th century did not result from the increase in precipitation amount. 2) Moreover, multi-scale characteristics of flood disaster and precipitation have been detected. The main periods of flood disaster are 2.7-year, 5.2-year, 9.9-year, 20.5-year and 51.6-year, and the periods of precipitation series corresponds well with those of the flood disaster series. 3) The magnification of flood disasters in the 1980s and 1990s did not result from the increase in precipitation amount, while the increment of rainfall intensity and extreme rainfall events play an important role in the process. And the human factors such as aggravation of soil and water loss and lake reclamation are also the driving forces contributing to the increment of flood disaster. Additionally, there is significant negative relationship between flood change and strength of investment in water resources.
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    Inter-monthly Response Characteristics of NDVI to the Variation of Temperature and Precipitation in East China and Its Surrounding Areas
    CUI Lin-li, SHI Jun
    2011, 26 (12):  2121-2130.  doi: 10.11849/zrzyxb.2011.12.011
    Abstract ( )   PDF (648KB) ( )   Save
    The interaction between vegetation and atmosphere is important in global climate change and natural resource management and has become a research focus of geosciences in recent years. Spatial and temporal response characteristics of NDVI to the variations of temperature and precipitation in East China and its surrounding areas were analyzed based on the SPOT VGT-DN data from Flemish Institute for Technological Research (VITO), Belgium, and monthly temperature and precipitation data from 135 meteorological stations during 1998-2010. The results indicate that in the whole study area, NDVI has the maximum response to the temperature of the same month, and has the maximum response to the precipitation of previous one month. Spatially, the response of NDVI to temperature has no significant difference among the whole study area, and the response of NDVI to precipitation in the northern part is stronger than that in the middle and southern part of the study area. In the middle part of the study area, NDVI synchronously responds to the variation of temperature in the current month, but in the northern and southern part, it responds to the variation of temperature with a lag of about one month. In the northern part of the study area, NDVI generally responds to the variation of precipitation with a lag of about one month, but in the southern part, it responds to the variation of precipitation with a lag of 2 or 3 months. The temporal response characteristics, spatial distribution and the general lag time of the NDVI to temperature and precipitation in East China and its surrounding areas are consistent with other results, but in the southern part, the lag time of NDVI to the variation precipitation is longer than other results. The difference of data source, study area, climate and vegetation type, and soil property may result in the difference between our and other results.
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    The Impacts of River Water Resources on Regional Climate over the Upper Yellow River High Cold Region
    Lü Ji-qiang, SHEN Bing, MO Shu-hong, SHAO Nian-hua, QIN Yi
    2011, 26 (12):  2131-2140.  doi: 10.11849/zrzyxb.2011.12.012
    Abstract ( )   PDF (661KB) ( )   Save
    In this paper, time series of 49 years monthly runoff, temperature, precipitation and part of the permafrost monitoring data recorded at Jimai control hydrometrical station and Maduo and Dari weather stations in the upper Yellow River high cold region were studied. The annual variation, interannual variation, main influencing factors of river water resources, were investigated using peak pattern analytical method, rate change of wetness-dryness analytical method, Mann-Kendall test, wavelet analysis and grey relational analysis, etc. The river water resources regime in 2008-2014 were obtained by Kernel Principle Component Analysis and Least Square-Support Vector Machines prediction model. The results showed that river runoff demonstrates obvious evolutionary characteristics, the year 1961 is the first catastrophe point at which the runoff begins an upward tendency, it begins to reduce after 1982, until 1999 the second catastrophe point which brought a significantly downward tendency. The results of wavelet analysis and the trend prediction analyses show that the hydrological regime in this area will be little more than the 1990s which will last 3-9 years; after 1986, the maximum seasonal frozen depth reduced, which exacerbated the total annual runoff reduction in upper Yellow River. The prediction results indicate that the river water resources in 2011-2014 will reduce by 25.3% the annual average water resources.
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    Resources Research Methods
    Productivity Evaluation of Standard Cultivated Land Based on Rough Set and Support Vector Machine
    LAI Hong-song, WU Ci-fang
    2011, 26 (12):  2141-2154.  doi: 10.11849/zrzyxb.2011.12.013
    Abstract ( )   PDF (519KB) ( )   Save
    Standard Cultivated Land (SCL) is the gem of all cultivated land, which is the key of ensuring China's grain security. Scientific evaluating productivity of SCL has a significant sense for improving soil productivity and improving soil of SCL. Integrated Rough Set (RS) theory with Support Vector Machine (SVM),a productivity evaluation method of SCL based on RS and SVM is proposed. Combining the parallel searching structure of genetic algorithms with the probabilistic jumping property of simulated annealing, a GASA-optimized algorithm is put forward for selecting of SVM parameters. In this new evaluating method, on the basis of determining productivity evaluation indexes of SCL, firstly the decision making table is constructed by using the sample data of productivity surveying of SCL and its evaluation results of traditional integrated productivity factors method, and the redundant indexes are removed through the exhaustive reducer of Rosetta software which was jointly developed by Norwegian University of Science and Technology and Warsaw University, then the reduced indexes are used as the input of SVM, finally, the SVM is trained with the training samples through the GASA-optimized algorithm, and the RS-SVM evaluating model of SCL is built. The method is tested on productivity evaluation of SCL of Lucheng District of Wenzhou City, Zhejiang, and its results are compared with that of the SVM without RS reduction method and the BP networks without RS reduction method. The input indexes of the SVM model and the BP networks model are both 15, With correct evaluating rate being 100% and 90% respectively. The input indexes of the RS-SVM model are 14, whose correct evaluating rate is 100%. The results indicate that the suggested SVM method is of the same accuracy as the SVM without RS reduction method,but it can reduce the dimensions of SVM input vectors and the computing complexity of SVM,and raise the SVM training efficiency. The results also show that the method which is used SVM can achieve greater evaluating accuracy than the BP networks without RS reduction method. It is concluded that the suggested SVM method is feasible and effective in evaluating productivity of SCL, and this method has explored a new way for evaluating productivity of cultivated land.
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    Special Forum
    A Review on Crop Yield Gaps and the Causes
    FAN Lan, Lü Chang-he, CHEN Zhao
    2011, 26 (12):  2155-2166.  doi: 10.11849/zrzyxb.2011.12.014
    Abstract ( )   PDF (464KB) ( )   Save
    Yield gap is the difference between actual yield and potential yield of a crop. Research on yield gap is to survey the magnitude and regional variation of crop yield gaps, analyze the causes and seek measures to narrow or close the gap. Yield gap means the chance for agricultural development. Understanding the magnitude of yield gap and potential to increase crop yield is of great importance for improving food production to meet the growing food demand. This paper firstly discussed the definition and methods of yield gap, and then presented yield gaps of wheat, maize, rice and soybean in the world and in China by literature study. Followed in third section, the factors and their contribution to the yield gap were identified, including meteorological hazards, crop species, water and nutrients, disease, pest and weeds, soil and crop management, and agro-technologies, as well as economic and policy factors. Finally, future research focuses of yield gaps were discussed.
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    Evolution of Classification and Enlightenment of Water Supply, Sewerage Disposal, Waste Management and Remediation Activities of International Standard Industrial Classification
    LIAN Tong-hui, YUAN Qin-jian
    2011, 26 (12):  2167-2174.  doi: 10.11849/zrzyxb.2011.12.015
    Abstract ( )   PDF (342KB) ( )   Save
    International standard industrial classification is the most mature, authoritative and influential international standards of the world classification of economic activity. Understanding the evolution of water supply, sewerage disposal, waste management and remediation activities in ISIC is essential to collect, process, calculate the financial indicators and compare data between countries. Therefore, this paper studies the classification of the evolution of water supply, sewerage disposal, waste management and remediation activities in ISIC, and puts forward some suggestions for improving classification of Chinese water supply, sewerage disposal, waste management and remediation activities industry.
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