共查询到18条相似文献，搜索用时 656 毫秒
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三峡库区退耕坡地环境移民压力研究 总被引：6，自引：3，他引：6
坡耕地退耕还林还草作为生态环境建设的重要措施正在三峡库区逐步实施。然而，坡耕地退耕将减少退耕地区的耕地数量，特别是坡耕地集中分布的区域，从而引发环境移民问题。利用GIS技术建立了基于GRID的坡耕地退耕压力指数模型及环境移民模型，并对三峡库区坡耕地退耕引发的潜在环境移民的数量进行模拟。模拟结果表明三峡库区坡耕地退耕引发的潜在环境移民数量较大。在退耕压力指数为40％时潜在环境移民数量高达89万人，相当于三峡水库淹没需要安置的水库移民数量。环境移民压力是该地区生态环境建设面临的一大难题。 相似文献
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基于坡耕地与聚落空间耦合的三峡库区腹地奉节县人地关系研究 总被引：5，自引：0，他引：5
《地理研究》2015,(7)
以三峡库区腹地奉节县的27个乡镇为例,应用网格分析技术,以1 km×1 km网格为单元,揭示了聚落与坡耕地资源之间的配置关系以及不同岩性区聚落—坡耕地耦合模式差异,并对研究区人地关系做了类型划分。结果表明:1奉节县27个乡镇聚落和坡耕地的空间分布表现出较强的空间趋同性,二者用地比、斑块等级大小高值都主要位于北部梅溪河河谷和中部长江河谷地区,低值主要分布于南部石灰岩地区;2坡耕地偏多型主要分布于砂岩区,坡耕地偏少型主要分布于石灰岩区,而坡耕地—聚落均衡型则表现出随机分布格局;3研究区坡耕地大量存在的原因主要归结于坡耕地基数大和坡耕地退耕难度大。受坡耕地分布的影响,坡耕地偏多型的土壤侵蚀较其他耦合类型严重;4 27个乡镇人地关系划分为人地矛盾突出型、人地矛盾较突出型、人地矛盾较缓和型和人地矛盾缓和型四种类型,而人地矛盾较突出类型所占比重最大,面临着退耕压力和耕地压力突出的双重问题。 相似文献
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以三峡库区腹地奉节县的27个乡镇为例,应用网格分析技术,以1km×1km网格为单元,揭示了聚落与坡耕地资源之间的配置关系以及不同岩性区聚落-坡耕地耦合模式差异,并对研究区人地关系做了类型划分。结果表明：①奉节县27个乡镇聚落和坡耕地的空间分布表现出较强的空间趋同性,二者用地比、斑块等级大小高值都主要位于北部梅溪河河谷和中部长江河谷地区,低值主要分布于南部石灰岩地区;②坡耕地偏多型主要分布于砂岩区,坡耕地偏少型主要分布于石灰岩区,而坡耕地-聚落均衡型则表现出随机分布格局;③研究区坡耕地大量存在的原因主要归结于坡耕地基数大和坡耕地退耕难度大。受坡耕地分布的影响,坡耕地偏多型的土壤侵蚀较其他耦合类型严重;④27个乡镇人地关系划分为人地矛盾突出型、人地矛盾较突出型、人地矛盾较缓和型和人地矛盾缓和型四种类型,而人地矛盾较突出类型所占比重最大,面临着退耕压力和耕地压力突出的双重问题。 相似文献
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黄土高原水土流失区生态退耕对粮食安全的影响 总被引：11，自引：0，他引：11
退耕还林是黄土高原水土流失区改善生态环境的一种有效途径,但在一定程度上必然会影响到区域的粮食安全,其中最直接最主要的影响便是退耕带来耕地面积减少,引发粮食总产量的降低。根据黄土高原水土流失区的生态退耕规划,对退耕还林还草可能对当地造成的粮食生产影响进行分析。利用具有显著科学性和可操作性的最小人均耕地面积和耕地压力指数模型,对该区各亚区进行了粮食安全评价,并以此为基础提出了黄土高原水土流失区各亚区退耕还林还草与粮食安全的协调途径。 相似文献
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陕北地区退耕还林还草工程土壤保护效应的时空特征 总被引：3，自引：0，他引：3
以中国退耕还林生态工程重点区域陕北地区作为研究区,基于耕地遥感监测数据集,分析了陕北地区2000-2013年耕地的时空变化特征;基于梯田空间分布,对RUSLE模型进行改进,模拟生成陕北地区土壤侵蚀模数栅格数据并进行精度验证;最后结合耕地变化数据集对陕北地区退耕还林（草）地及未退耕地的土壤侵蚀变化特征进行对比分析,以明确工程对全区土壤侵蚀变化的影响。结果表明,2000-2010年,陕北退耕农田内部侵蚀模数减少了22.70 t/hm 2,是退耕农田区2000年土壤侵蚀模数的47.08%。同期,陕北地区未退耕农田侵蚀模数减少了10.99 t/hm 2,占未退耕农田区域2000年土壤侵蚀模数的28.60%。从陕北全区的角度看,各种土地利用类型2000-2010年土壤侵蚀模数平均减少了14.51 t/hm 2,占2000年全区土壤侵蚀模数的41.87%。由此可见,退耕还林还草工程可以有效减少土壤侵蚀模数,达到土壤保护的作用。其中,由耕地转为林草所导致的侵蚀减少最为显著,对土壤保护的贡献作用最大。但是,2010年以后（2010-2013年）为退耕还林还草巩固时期,因此该阶段陕北地区土壤侵蚀模数和土壤侵蚀量变化较前10年显著降低。 相似文献
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基于不同退耕模式的黄土丘陵区生态环境建设地域分异特征 总被引：2，自引：0，他引：2
退耕是目前国家关于黄土丘陵区生态环境建设的主体措施。在总结"赈济退耕25"、"赈济退耕15"和"梯田退耕"各模式基本特点的基础上,根据土地利用、耕地坡度分级数据、农业人口数据和不同模式生态环境建设标准,分别计算了黄土丘陵区各县(市、区)退耕25°和15°以上坡耕地、新建园地、新修梯田、林草植被恢复的面积以及相应的投资需求额度。在构建并采用生态环境建设指数、政策性补贴资金密度指数和投资需求密度指数等指标,对55个县(市、区)进行类型划分的基础上,分析了黄土丘陵区不同退耕模式下的生态环境建设规模及投资需求地域分异特征。 相似文献
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元江干热河谷区坡耕地景观格局变化研究 总被引：1，自引：0，他引：1
基于元江干热河谷区1990年、2000年和2010年三期土地利用数据为基础,利用景观生态学原理选取8个景观指数,定量分析坡耕地景观格局的变化。结果表明:元江干热河谷区坡耕地面积大、比例高,退耕还林还草工程成效显著,2010年坡耕地的空间分布格局接近于1990年。坡耕地向坡度小的区域扩张,25°以上的陡坡耕地面积变化不大。500~800 m的海拔范围坡耕地分布面积最广,且斑块最为复杂和破碎。距离河流越近坡耕地分布面积越大、坡耕地斑块越破碎。 相似文献
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长江上游丘陵区社会经济实力与坡耕地治理--以四川省中江县为例 总被引：4，自引：0，他引：4
以长江上游丘陵区重点水土流失区内的四川省中江县为例，借助GIS技术，分析了坡度和水土流失约束下的耕地状况，选取农民人均纯收入、人均粮食产量和人均GDP作为评价指标，以乡为评价单元，进行了坡耕地治理的社会经济实力综合评价，进而探讨了坡耕地治理的相关措施。分值在80～100间的乡镇应以大规模的改造坡耕地(坡改梯)、建设基本农田为突破口，为解决粮食问题和实现陡坡地退耕创造条件，退耕还林还草应将经济效益、生态效益和社会效益融于一体。分值在65-80间的乡镇应结合坡耕地综合治理和基本农田建设，发展生态农业，逐步实施退耕还林。分值在0～65间的乡镇应注重陡坡耕地水土流失的防治和土地利用技术的应用。不宜近期退耕。此外，通过加强农村居民点整理增加耕地，可在一定程度上解决陡坡退耕带来的粮食问题，为退耕还林还草、防治水土流失工作的顺利开展提供保障。 相似文献
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重庆市山区农户耕地转入特征及其影响因素 总被引：3，自引：1，他引：2
耕地流转有利于缓解耕地撂荒和闲置问题,促进土地规模化经营,但已有山区的研究侧重耕地转出,且未深入分析农户耕地转入的特征.本文运用重庆市“两翼”地区12 个典型村的1015 份农户调查问卷,从地块尺度详细分析了农户耕地转入的特征,并通过Tobit 模型,定量分析了农户转入耕地面积的影响因素.结果表明:①农户多无偿转入耕地,但仍主要转入质量好、坡度小、离家近的地块;因受地形影响,转入地块又多为旱地,且难灌溉、面积小,并存在“去粮化”和粗放化经营.②农户特征方面,转入耕地的农户多为普通农户,经营耕地规模小、效益低,且地块细碎化程度高.③影响因素方面,农业劳动力比例、农业收入、农具数量和耕作面积对农户转入耕地面积有显著正向影响,而户主年龄、地块平均面积和地区哑变量则武隆县有显著负向影响. 相似文献
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The project of 'grain for green', to restore woodland and grass by retreating from slope farmland, as a fundamental measure of eco-environmental rehabilitation, is being conducted in the reservoir area of the Three Gorges gradually. However, the de-farming of slope farmland will reduce the amount of farmland in de-farmed areas, especially in the areas with concentrated slope farmland, which would cause the problems of environmental emigration. The people who cannot regain enough farmland by relocating farmlands within village after de-farming and have to emigrate to other places are called environmental emigrants or ecological emigrants. In the research, a de-farming stress index model and an environmental emigration model are developed based on GRID data, and the potential amount of environmental emigration caused by de-farming of slope farmland in the reservoir area is simulated aided with GIS. The simulation indicates that the potential emigration amount caused by de-farming is quite large. When the de-farming stress index reaches 40%, the amount is as large as 890,000 people, which is equivalent to the emigrants caused by the submergence of the Three Gorges reservoir. So it should be considered as a big problem during the eco-environmental rehabilitation in this area. Some suggestions are raised to tackle the problem. Firstly, the emigration plan should be included in the de-farming plan. Secondly, some provinces, especially those located in the lower reaches of the Yangtze River, should accommodate part of the environmental emigrants. 相似文献
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The project of ‘grain for green’, to restore woodland and grass by retreating from slope farmland, as a fundamental measure
of eco-environmental rehabilitation, is being conducted in the reservoir area of the Three Gorges gradually. However, the
de-farming of slope farmland will reduce the amount of farmland in de-farmed areas, especially in the areas with concentrated
slope farmland, which would cause the problems of environmental emigration. The people who cannot regain enough farmland by
relocating farmlands within village after de-farming and have to emigrate to other places are called environmental emigrants
or ecological emigrants. In the research, a de-farming stress index model and an environmental emigration model are developed
based on GRID data, and the potential amount of environmental emigration caused by de-farming of slope farmland in the reservoir
area is simulated aided with GIS. The simulation indicates that the potential emigration amount caused by de-farming is quite
large. When the de-farming stress index reaches 40%, the amount is as large as 890,000 people, which is equivalent to the
emigrants caused by the submergence of the Three Gorges reservoir. So it should be considered as a big problem during the
eco-environmental rehabilitation in this area. Some suggestions are raised to tackle the problem. Firstly, the emigration
plan should be included in the de-farming plan. Secondly, some provinces, especially those located in the lower reaches of
the Yangtze River, should accommodate part of the environmental emigrants. 相似文献
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三峡库区规模农地时空变化特征及其驱动机制 总被引：7，自引：1，他引：6
探讨库区农地利用的转型及其机制,可反映中西部结合带、山区、库区的农村变化和人与环境关系的变化,为典型山区的农业多功能转型发展方向提供科学依据。选取三峡库区腹地5个区县为研究区,通过定义“规模农地”相关概念,利用ArcGIS 10.2软件并结合SPSS、地理空间探测器等技术手段对规模农地的变化与机制进行分析。研究发现：规模农地的转移来源主要由耕地和灌木林地组成,除部分高山反季节蔬菜,规模农地的增长一般发生在低海拔地区,且在坡度30°范围内均有分布;不同类型的规模农地空间变化有所不同,但均与道路和乡镇级行政中心的关系明显。斑块水平上,高程、坡度等自然因素对规模农地的贡献相对较大;乡镇水平上以道路交通、农业人口密度等社会经济与人文因素驱动力为主;区域水平上,各区县的驱动因子影响力较研究区整体尺度更为显著。规模农地的变化与发展受多种因素驱动,但农业政策始终是各驱动因素的主导,不同水平的行为主体会促使规模农地发展趋向不同的方向,但原则上均受国家农业发展现状与政府政策导向影响。 相似文献
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In the past 40 years,cultivated land has faced the continued anthropogenic inter-ference,which has become a significant issue for cultivated land preservation during rapid urbanization.The purpose of this research was to reveal the spatio-temporal evolutionary characteristics of cultivated land and the correlation between rural population variation and farmland change in China.Fifty county-level administrative units in Zhejiang Province were selected as the study area wherein spatio-temporal evolution comparative analysis for every 5 years from 2000 to 2015 was conducted.This study used the pool method to estimate the impacts of the rural population variation,average slope,average elevation,rural residential disposable income,primary industry proportion,and road density on farmland utilization efficiency from the spatial perspective,which is represented by landscape metrics including the mean patch size,edge density,area weighted mean shape index,and area weighted mean patch fractal dimension.This study showed that the cultivated land landscape index continued to rise after 2000 and then started decreasing after 2010,indicating a reduction in human interference after 2010.The spatial variation of rural population of all county-level administrative units decreased from 2000 to 2010,and 62％of them began to increase after 2010.The regression analysis results showed that the spatial variation of rural population was significantly and negatively correlated with the cultivated land landscape while the rural residential disposable income,average slope and primary industry proportion were all sig-nificantly and positively related to the cultivated land landscape index.The results implied that the loss of the agricultural labor force and the difficulty of sloping farmlands adapting to mechanized farming were unconducive to farmland utilization efficiency improvement,and the increase in nonagricultural activities in rural areas would increase the difficulty of culti-vated land preservation.Our analysis suggests that local governments should improve the production efficiency of fragmented land or strengthen the construction control of housing and facilities in rural areas according to their regional urbanization development situation. 相似文献
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农村居民点耕作距离空间分布特征估测分析 总被引：10，自引：2，他引：8
基于探索性空间数据分析(ESDA)思想,提出一种耕作距离空间估测方法,定量分析农村居民点耕作距离的分布格局与分异特征。以广东省阳山县为案例,研究表明：① 耕作距离与耕地质量及地形等别存在一定的相关性,耕作半径愈小,地形愈低平的地区,居民点与较优的耕地愈集中;② 耕作距离在空间上呈现不均衡状态,随着距离尺度的增加,耕作距离的变化由低值聚类转为高值聚类状态,表明研究区耕地格局随耕作距离尺度上升变得更加分散;③ 估测方法考虑了农村居民点与耕地之间的关系,可以有效分析耕地与居民点之间的空间分布随耕作距离变化的规律,对农村居民点调整、高标准农田建设等工作的合理开展具有参照和一定指导意义。 相似文献
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基于RS和GIS的土地生产力与人口承载量──以向家坝库区为例 总被引：11，自引：2，他引：9
本文在分析土地生产力与承载力研究现状的基础上 ,以向家坝库区耕地为研究对象 ,根据库区经济地理现状 ,确定土地人口载量研究区域 ,并利用GIS和RS技术对研究区土地利用现状和地形地貌特点进行深入分析 ,建立“空间·属性一体化”数据库。本文还建立了土地资源人口承载量评价指标体系 ,利用潜力递减法 ,进行以村级为单位的耕地粮食综合村尺度的近期和远景 (2 0 12 )土地人口承载量研究 ,提出与当地农业发展相一致的整个研究区环境容量。结果表明 ,与其它耕作方式相比 ,复种耕种可获得更大的人口承载量 ;库区环境容量已趋饱和 ,而且未来库区土地承载力呈下降趋势 ;通过改良品种、扩大水稻播种面积可在一定程度上缓解地矛盾。 相似文献
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Farmland resources in mountainous areas are important for regional food security and ecological security. Studies concerning changes in farmland use in mountainous areas are of considerable significance in China. Here, we analyzed marginalization characteristics of farmland in Renhuai city from 2005 to 2011 and driving factors using land information systems, surveys of farmer households and statistical data. Our results indicate that from 2005 to 2011, 3095.76 hm2 of farmland was converted to forest land and natural reserve, accounting for 5.45% of the total farmland area. This suggests significant marginalization of farmland. Marginalization of farmland in mountainous areas was affected by topography, labor forces and effectiveness of land management. Farmland with a greater slope gradient was more likely to be abandoned; among marginalized land in Renhuai, a slope greater than 15° accounted for 62.26%. A high non-agricultural employment rate of rural labor force and annual income per capita of farmer households in mountainous areas were consistent with high speed farmland marginalization. Low land management benefits were the key reason for farmland marginalization. Although farmland marginalization was advantageous for eco-environment protection and sustainable development in mountainous areas, it resulted in inefficient land resource utilization. A win-win model for the exploitation and utilization of sloping farmland should be explored for production development and environmental protection. 相似文献