[Objective] The modified variable weights based on constant weight and in- troduced theory of equalization function would better incorporate authentic index weights and make evaluation results of fertility more scient...[Objective] The modified variable weights based on constant weight and in- troduced theory of equalization function would better incorporate authentic index weights and make evaluation results of fertility more scientific. [Method] In Gaozhou City, the final weights of influential factors can be determined with the help of GIS and as per AHP and theory of variable weights. In addition, farmland fertility was e- valuated in an automatic and quantitative way and the spatial distribution pattern was analyzed as per fuzzy comprehensive evaluation. [Result] For farmlands at 58 505.027 8 hm2 in the city, farmlands from grade 1 to grade 8 account for 3.62%, 18.27%, 33.15%, 26.96%, 13.66%, 3.29%, 0.81% and 0.24%, respectively, which is in consistent with local condition. [Conclusion] These results have been applied di- rectly in test regions and constitute a rewarding exploration for fertility evaluation in South China.展开更多
以"传播新知识、交流新思想、展示新成果"为宗旨的中国生态大讲堂百期学术演讲暨2014年春季研讨会于2014年4月25日在北京举行。本次研讨会以"国际重大研究计划与中国生态系统研究展望"为主题,邀请秦大河、姚檀栋、...以"传播新知识、交流新思想、展示新成果"为宗旨的中国生态大讲堂百期学术演讲暨2014年春季研讨会于2014年4月25日在北京举行。本次研讨会以"国际重大研究计划与中国生态系统研究展望"为主题,邀请秦大河、姚檀栋、傅伯杰、崔鹏4位中国科学院院士和马克平、于贵瑞、张佳宝、秦伯强4位知名专家作了主题报告。8位报告人分别介绍了政府间气候变化专门委员会(IPCC)、未来地球(Future Earth)、第三极环境(Third Pole Environment)、国际长期生态监测研究网络(ILTER)、生物多样性和生态系统服务政府间科学—政策平台(IPBES)、生物多样性计划(DIVERSITAS)、通量观测研究计划(FluxNet)等国际重大研究计划的进展和趋势,并就山洪泥石流风险分析与管理、碳通量空间格局及生物地理生态学机制、农田地力提升和湖泊富营养化治理等领域的前沿科学问题和研究进展作了系统阐释。基于8位报告人的演讲,本文评述了8个报告的主要内容和亮点工作,分析了国际生态环境领域重大国际研究计划的发展趋势及其对中国生态系统研究的启示,讨论了中国相关领域的科学研究方向和主要问题。展开更多
In this paper,we mainly focused our research on northern Shaanxi district,which is a pilot area of the Grain for Green Project.We compared the spatial distribution patterns of croplands and their productivity for the ...In this paper,we mainly focused our research on northern Shaanxi district,which is a pilot area of the Grain for Green Project.We compared the spatial distribution patterns of croplands and their productivity for the past 20 years（from the end of the 1980 s to 2010）.Cropland dynamics for the past 20 years were interpreted from medium- and high-resolution remote sensing images（Landsat TM/ETM＋）.In addition,using the GLO-PEM and AGRO-VPM models with a medium resolution and long time series remote sensing dataset（AVHRR/MODIS）,net primary productivity（NPP） and its relationship with cropland were estimated.Finally,the effect of cropland change on productivity was analyzed.The results show that during the first decade of the research period,cropland area and productivity in northern Shaanxi experienced a small boost,while in the latter decade,both cropland area and NPP were significantly reduced.The main cause of the increase in cropland was the reclamation of large area of grassland and unutilized land to meet the food demands of the local population as well as to compensate for the occupation of urban constructions.While the main cause of the decrease in cropland was the implementation of the Grain for Green Project.In addition,urbanization was also a key factor.Overall,during the past 20 years,the total area of cropland in northern Shaanxi decreased by 42.56%,and cropland NPP dropped by 41.90%.This study is of great importance for the assessment of regional cropland security,food security and scientific planning of regional land use.展开更多
基金Supported by Project on the Integration of Industry,Education and Research ofGuangdong Province(2010B090400155)Guangdong Science&Technology Plan Pro-ject(2009B020315012)~~
文摘[Objective] The modified variable weights based on constant weight and in- troduced theory of equalization function would better incorporate authentic index weights and make evaluation results of fertility more scientific. [Method] In Gaozhou City, the final weights of influential factors can be determined with the help of GIS and as per AHP and theory of variable weights. In addition, farmland fertility was e- valuated in an automatic and quantitative way and the spatial distribution pattern was analyzed as per fuzzy comprehensive evaluation. [Result] For farmlands at 58 505.027 8 hm2 in the city, farmlands from grade 1 to grade 8 account for 3.62%, 18.27%, 33.15%, 26.96%, 13.66%, 3.29%, 0.81% and 0.24%, respectively, which is in consistent with local condition. [Conclusion] These results have been applied di- rectly in test regions and constitute a rewarding exploration for fertility evaluation in South China.
文摘以"传播新知识、交流新思想、展示新成果"为宗旨的中国生态大讲堂百期学术演讲暨2014年春季研讨会于2014年4月25日在北京举行。本次研讨会以"国际重大研究计划与中国生态系统研究展望"为主题,邀请秦大河、姚檀栋、傅伯杰、崔鹏4位中国科学院院士和马克平、于贵瑞、张佳宝、秦伯强4位知名专家作了主题报告。8位报告人分别介绍了政府间气候变化专门委员会(IPCC)、未来地球(Future Earth)、第三极环境(Third Pole Environment)、国际长期生态监测研究网络(ILTER)、生物多样性和生态系统服务政府间科学—政策平台(IPBES)、生物多样性计划(DIVERSITAS)、通量观测研究计划(FluxNet)等国际重大研究计划的进展和趋势,并就山洪泥石流风险分析与管理、碳通量空间格局及生物地理生态学机制、农田地力提升和湖泊富营养化治理等领域的前沿科学问题和研究进展作了系统阐释。基于8位报告人的演讲,本文评述了8个报告的主要内容和亮点工作,分析了国际生态环境领域重大国际研究计划的发展趋势及其对中国生态系统研究的启示,讨论了中国相关领域的科学研究方向和主要问题。
基金National Basic Research Program of China(2010CB950900)National Key Technology R&D Program(2013BAC0304)
文摘In this paper,we mainly focused our research on northern Shaanxi district,which is a pilot area of the Grain for Green Project.We compared the spatial distribution patterns of croplands and their productivity for the past 20 years（from the end of the 1980 s to 2010）.Cropland dynamics for the past 20 years were interpreted from medium- and high-resolution remote sensing images（Landsat TM/ETM＋）.In addition,using the GLO-PEM and AGRO-VPM models with a medium resolution and long time series remote sensing dataset（AVHRR/MODIS）,net primary productivity（NPP） and its relationship with cropland were estimated.Finally,the effect of cropland change on productivity was analyzed.The results show that during the first decade of the research period,cropland area and productivity in northern Shaanxi experienced a small boost,while in the latter decade,both cropland area and NPP were significantly reduced.The main cause of the increase in cropland was the reclamation of large area of grassland and unutilized land to meet the food demands of the local population as well as to compensate for the occupation of urban constructions.While the main cause of the decrease in cropland was the implementation of the Grain for Green Project.In addition,urbanization was also a key factor.Overall,during the past 20 years,the total area of cropland in northern Shaanxi decreased by 42.56%,and cropland NPP dropped by 41.90%.This study is of great importance for the assessment of regional cropland security,food security and scientific planning of regional land use.
