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1.
In this study, the Land Use Dynamic Simulator model was applied to investigate the impact of farm credit as an adaptation strategy to cope with effects of climate variability on agricultural land‐use change and crop production in the Vea watershed in Ghana. The authors identified the determinants of crop choices within the landscape (e.g., farm household and biophysical characteristics of farm plot). The crop choice sub‐model was then linked to the crop yield sub‐model to determine the yields of selected crops. In adapting to the impacts of climate variability, the maize credit adoption sub‐model under the maize cultivation credit scenario was integrated into decision‐making. This was simulated for a 20‐year period, and compared with the business‐as‐usual scenario. Under the simulated maize credit scenario, maize adopters increased from about 20 per cent to about 50 per cent and the area allocated for maize cultivation significantly increased by about 266 per cent. Consequently, the average annual aggregated household crop yield increased by 6.3 per cent higher than in the business‐as‐usual scenario. This simulation study shows that access to maize credit can significantly influence agricultural land‐use change and food availability in the study area. However, although access to farm credit may translate into food availability, the sustainability of this strategy is questionable.  相似文献   

2.
The paper measures the level of crop diversity and identifies factors influencing diversification using a panel data of 17 regions of Bangladesh covering a 19 year period (1990–2008). Results revealed the trends that agricultural areas allocated to high‐yielding variety rice, spices and vegetables has increased, while areas cultivating traditional rice, minor cereals, oilseeds, pulses, jute and sugarcane has declined at variable rates across regions with significant differences. The level of crop diversity is also significantly different across regions and has decreased in 2008 from its 1990 level in most regions except Faridpur, Khulna and Sylhet. Among the determinants, an increase in the relative prices of vegetables and urea fertilizer, extension expenditure, labour stock per farm, average farm size, irrigation and a reduction in livestock per farm significantly increase crop diversity. Price policies to improve vegetable prices and investment in irrigation infrastructure and extension services are suggested to promote crop diversity in Bangladesh.  相似文献   

3.
Population growth and land use in Nepal: "the great turnabout"   总被引：1，自引：0，他引：1  
Historically, Nepal has demonstrated a "great turnabout" trend, in which initial immigration from the lowland areas to the mountains has been replaced by accelerating migration from the hills to the plains. The reason for this reversal has been a rapid growth in population within the confines of limited availability of potentially cultivable land. Given Nepal's slow economic development, the overwhelming majority of increases in population have to be accommodated within the agricultural sector, on which 83% of Nepal's households are dependent. Fundamental land use issues in Nepal include rapid achievement of the final limit of land suitability for cultivation and the speed at which land can be brought into cultivation. The Government of Nepal has developed the objectives of increased food production to provide a satisfactory diet for the population, increased per capita income, improved regional balance in income and development, conservation of natural resources such as land and forests, and overall development of the economy through income generation, export earnings, and release of agricultural labor to other sectors. 3 perspective studies have identified a number of policies and programs that could bring Nepal closer to these goals. These studies analyzed potential land use development, agricultural production, and food availability by the year 2005. Most essential is the need to intensify land use not only in crop agriculture, but also grasslands and forest use. Land must be allocated to uses that represent the most productive use of that land without being degrading. Technologies are available for land use in each of the main types of uses--crop agriculture, livestock, and forests--that can provide protection against land degradation. Finally, irrigation is a key element in raising agricultural output. Close cooperation between the government and the people is crucial for the success of the task of finding a balance between population growth and its demand for services of the land.  相似文献   

4.
河南省小麦生产的区域差异及其对农用地分等的影响   总被引：3，自引：0，他引：3  
河南是农业大省,粮食产量居全国首位,但全省粮食产量区域差异比较明显,豫东平原、豫北山前平原、南阳盆地为主要产粮区,而西部山区粮食生产力低下。农用地质量的优劣直接决定着粮食产量的高低,而作物的生产潜力和现实生产力影响着农用地质量的好坏。一般来说,作物生产潜力空间分布具有明显的南北纬度地带渐变规律,现实生产力则是在土地的自然属性融入社会经济因素而导致的土地投入和利用上的差异。文章以小麦为例,主要从潜在生产力和现实生产力2个方面阐述了造成小麦产量区域差异的原因并分析了它们对农用地分等产生的影响。  相似文献   

5.
刘成武  黄利民 《地理研究》2015,34(12):2268-2282
认识农地边际化过程中农户土地利用行为的变化及其对粮食生产的影响,对正确判断中国的粮食生产形势,制订相关政策以确保粮食安全具有重要意义。基于湖北省咸宁市4县1市1区的23个村组、1252个农户家庭的调查数据,对1981年以来农户土地利用行为变化的特征及其对粮食生产的影响进行分析。结果表明：① 农户用于粮食生产的劳动力与土地面积明显下降,农户用地方式出现“省工性”变化,劳动力被农机要素替代,农业机械、化学肥料与农药等物质投入显著上升。② 主要粮食作物的劳动生产率、土地生产率与商品率分别提高了4.61%、29.69%与50.56%,但区域主要粮食作物的总产量与农户家庭平均粮食占有量却分别下降了10.49%与10.50%,区域粮食安全的保障能力出现弱化。③ 丘陵山区主要粮食作物的“三率”提高幅度高于平原地区,丘陵山区的水稻总产量与家庭占有量均略有提高,但平原地区却出现了明显下降。产粮重心在空间上出现从平原地区向丘陵山区倾斜的现象。④ 稳定主要粮食作物的用地规模,促进农户规模经营,提高土地产出效率,是应对农地边际化作用的关键。从事规模化与专业化粮食生产的农区与农户,应成为国家惠农政策与粮食安全政策重点扶持的对象。  相似文献   

6.
19802000北京市农业土地生产性的变动分析   总被引：1，自引：0，他引：1  
王鹏飞  鲁奇  傅桦  李娟 《地理研究》2006,25(4):719-729
根据1980、1990、2000年的统计资料和实地走访观察,本文分析了北京市乡镇一级的粮食作物、蔬菜作物和果品作物的分布格局及农业土地生产性近20年的变化。研究认为:1980年北京农业生产分布格局与土地生产性为比较典型的杜能模式;随着农业经营的多样化,1990年和2000年北京农业土地生产性呈现出多样的分布格局;北京粮食作物、蔬菜作物、果品作物的分布格局及农业土地生产性近20年的变化与此阶段的农业生产政策、农业以外的社会经济活动变化有较强的关联性;对北京以上问题的研究为验证杜能、辛克利亚、布莱昂特城市周边农业地域研究经典理论的演变提供了实证案例。  相似文献   

7.
1980年以来北京农用地时空演变与驱动力   总被引：3，自引：1，他引：2  
王鹏飞  鲁奇  傅桦 《地理学报》2005,60(6):953-964
分析北京1980年、1990年、2000年的耕地率、粮食和蔬菜作物的种植率及粮食和蔬菜作物及果树作物的单位面积产量,得出北京农业用地变化类型由土地条件、国家政策和制度改革、农业生产技术进步、农村工业化、城市发展、栽培作物种类变化等多种驱动力的相互作用形成的。与人口密度进行量化相关分析后预测,到2020年北京粮食作物的生产会因生产技术的不断进步而有很大提高,其种植率将达到75%。蔬菜种植率将达到15%,显著增加地点在城市近郊外缘,城市近郊将有较大减少。果树栽培与其生产的分布格局则不会有太大变化。  相似文献   

8.
Rice is the main food crop in densely populated Bangladesh. Regional climatic variations can play an important role in rice productivity. For example, excessive heat or extremely cool conditions disrupt normal plant physiological processes and cause plant injury which, in turn, results in reduction of yield. In this study, the climatic crop productivity model YIELD has been applied to calculate rice productivity for the boro rice growing season (December/January-May) in Bangladesh under changing climatic conditions. The model estimates climatic influences on various rice plant-growth parameters. YIELD was tuned and validated to Bangladesh's environment to represent appropriate agroecological conditions. The model was run using long-term average climate data of 12 meteorological stations located in the major rice-growing regions in Bangladesh to establish baseline estimates of yield. For the climate change study, 20 scenarios were created by synthetically fluctuating thermal and solar climates in Bangladesh. Study results show that per 1° C increase in growing season mean air temperature, boro rice yield was reduced by 4.6%. It was also found that each 10% increase in incident solar radiation resulted in a 6.5% increase of boro rice yield in Bangladesh.  相似文献   

9.
Understanding the driving forces and mechanism of land use change is a key issue in land change science, and has received much attention over the past 30 years. While many driving forces have been identified, the mechanism of land use change is still unclear, mainly because of limited knowledge of the underlying motivation for land use change. Traditionally, the underlying motivation for land use change was ascribed to people＇s pursuit of satisfying their own demands or that of profit maximization. However, those theoretical hypotheses combine all productive factors without highlighting certain predominant factor, in this paper, a case study was conducted on the variation of land productivity, capital productivity and labor productivity in agricultural land use in Xinjiang Uygur Autonomous Region of China. The case study revealed that only labor productivity presented a long-term increasing trend in regional cotton and grain production. This result implies that people＇s pursuit of increasing labor pro- ductivity is probably the underlying motivation for land use change. Additional details identi- fied in agricultural and non-agricultural land use in China support the above implication. As labor productivity is a determinant of people＇s living standards, increasing labor productivity means improving people＇s living standards. Therefore, it is concluded that land use change results from people＇s pursuit of increasing labor productivity in a changing environment.  相似文献   

10.
王鹏飞 《地理研究》2005,24(3):453-463
运用政治生态学(politicalecology)的基本观点,以北京市农村地区为对象,在对平原、丘陵、山区4个不同类型村庄多年实地调查基础上,分析了在政治体制改革、市场经济影响下北京郊区农村的组织形态、产业结构、土地利用、耕地质量、生态环境的变化过程。研究揭示,1979以来北京农村政治改革与生态环境的关系与其他的农村地区不同,国家与地方政府的政策变化使北京农村生态环境在不同时期呈现出恶化-改善的波动性过程;根据长期研究,政体改革、政策变化在总体上起到了抑制生态恶化、改善农村环境的作用。  相似文献   

11.
This study evaluates land use/cover changes and urban expansion in Greater Dhaka, Bangladesh, between 1975 and 2003 using satellite images and socio-economic data. Spatial and temporal dynamics of land use/cover changes were quantified using three Landsat images, a supervised classification algorithm and the post-classification change detection technique in GIS. Accuracy of the Landsat-derived land use/cover maps ranged from 85 to 90%. The analysis revealed that substantial growth of built-up areas in Greater Dhaka over the study period resulted significant decrease in the area of water bodies, cultivated land, vegetation and wetlands. Urban land expansion has been largely driven by elevation, population growth and economic development. Rapid urban expansion through infilling of low-lying areas and clearing of vegetation resulted in a wide range of environmental impacts, including habitat quality. As reliable and current data are lacking for Bangladesh, the land use maps produced in this study will contribute to both the development of sustainable urban land use planning decisions and also for forecasting possible future changes in growth patterns.  相似文献   

12.
石羊河下游农户的土地利用行为及效率   总被引：1，自引：0，他引：1  
张丽琼  赵雪雁  郭芳  李文美 《中国沙漠》2015,35(6):1715-1722
农户的土地利用行为不仅决定着土地资源能否可持续利用,更影响着农村生态环境质量。本文以石羊河下游484户农户的问卷调查为基础,采用多独立样本和数据包络分析(DEA)法分析不同区域和不同类型农户土地利用行为的差异性和土地利用效率及影响因素。结果表明:(1)越向石羊河尾闾,粮食作物的种植比例越小,而经济作物种植比例越大;(2)坝区种植多样化指数最高,湖区农户土地的投入和产出最高,坝区与湖区土地利用的综合技术效率和规模效率均高于泉山区;(3)随着非农化水平的提高,农兼户的种植多样化指数最高,纯农户、农兼户和兼农户的土地投入与产出、综合技术效率、规模效率依次降低;(4)家庭规模、户主年龄、非农业收入与土地利用效率呈显著负相关性,劳动力受教育水平、农业总投入、农业收入与土地利用效率呈显著正相关性。最后,提出改善石羊河下游农户的土地利用行为、提高土地利用效率的对策建议。  相似文献   

13.
Even though cities cover approximately only 3 per cent of the earth's land area, they are often located on what previously was prime agricultural land. In line with what was common historically, many cities around the world are now deliberately seeking to promote and expand agricultural production within their borders. Pressure for change is coming from a number of sources, including both governments and private citizens. Potentially, community gardens and domestic backyard food production have an important role to play in this process, but while there now exists a sizeable body of research on the former, there is a serious lack of data on current productive practices in private domestic gardens. While other researchers have asked householders to estimate garden production, we believe this to be the first project to carefully document measured output by multiple households. The paper presents the results of a fine-grained study of 15 selected householders in metropolitan Melbourne. Participants collected detailed daily information about their food production over a three-month period. In addition, two of the respondents had been keeping daily production records continuously for one or more years. The results demonstrate enormous diversity in the food harvested, as well as some extremely high levels of productivity from relatively small domestic spaces. Participants were also questioned about their motivations for engaging in backyard food production and dealing with surpluses.  相似文献   

14.
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   

15.
Rapid change in land use and land cover (LULC) and unplanned urban expansion in Dhaka City, Bangladesh, receives continuous attention from local policymakers and the international community. This study employed a supervised classification procedure and postclassification change detection technique to estimate major changes between different LULC classes. The study revealed that built-up area increased significantly from 1989 to 2014. The total urban growth of 81.54 percent resulted in a substantial decrease in natural vegetation cover and agricultural land. In addition, water bodies have declined consistently over the last twenty-five years. The overall accuracy of LULC change maps produced from Landsat data ranged from 89.72 percent to 92.97 percent. The results should contribute to ongoing LULC information updates while forecasting possible future LULC change and sustainable development under greater population density.  相似文献   

16.
Mexico has a heterogeneous climate due to its geographical location. Half of the Mexican territory is dryland, mostly in the centre and north of the country, within which agriculture is the main activity in the primary production sector. At present, climate variability has a strong impact on Mexican agriculture. This study analysed rainfall variability, its impact on the agricultural productivity in terms of harvested quantity and productivity of 1996‐2014, and in parallel, the role that socioeconomic development plays on the well‐being of the population who live in areas with rainfed agriculture and a semi‐dry climate. The data obtained were analysed with the Statistical Analysis System. A positive correlation was found between rainfall and productivity (r = 0.76 for maize; r = 0.711 for beans). Rainfall variations therefore have a great impact on agricultural productivity, on food security and on the economy. Besides production losses, a parallel consequence is marginalization of the population because producers' income is increasingly reduced due to smaller crop volumes.  相似文献   

17.
The aim of this study is to establish several important factors representing land use intensification in cultivated land (denoted by CII), using a multi-dimensional approach to achieve realistic and practical cultivated land use policies in China. For this reason, the theoretical framework was first built to explain the changes of land use intensification in the cultivated land, and then the variables and index were further developed for the purpose of characterizing the dynamic trends and driving forces of the land use intensification in the cultivated land at the provincial level. The study results indicate that the extent of CII significantly increased during the period of 1996 to 2008, due to the extensive use of fertilizers, machinery and pesticide, increased labor and capital input, and intensified land use. Moreover, the principal component regression results show that the productivity of cultivated land, economic benefits of cultivated land, labor productivity, and land use conversion are the main factors affecting the village development. The first three factors play a positive role, while the last one has a negative effect on the land use intensification in the cultivated land. According to these results, the main policies for sustainable intensification in cultivated land are proposed. First, the sustainable pathways for intensification should be adopted to reduce the unsustainable uses of chemical fertilizer, agricultural chemicals, etc. Second, the conditions for agricultural production should be further improved to increase the cultivated land productivity. Third, it is very necessary and helpful for improving labor productivity and land use efficiency from the viewpoint of accelerated the cultivated land circulation. The last step is to positively affect the production activities of peasants by means of reforming the subsidy standards.  相似文献   

18.
Traditional agricultural land use systems in the humid tropics of the Southwest Pacific are, as elsewhere, affected by globalization processes. This paper analyzes the directions of change in the land use system of Bellona, a small outer island in the Solomon Islands. We focus on the human–environmental interaction that shapes land use patterns and practices in the context of theoretical lines of thought concerning intensification of agricultural systems in the tropics. Aerial photography from 1966 and satellite imagery from 2006 in conjunction with studies from the 1960s and a contemporary household survey reveal only minor changes in the agricultural system. Land use and land cover dynamics are related to agricultural strategies, demographic factors, institutional actors as well as biophysical drivers or constraints. Local agricultural production still contributes significantly to local subsistence but imported food has also become a major food source. Hence, land use has become partially disconnected from the local population pressure and therefore remains relatively stable while the larger livelihood portfolio has undergone significant diversification. At present, the agricultural system is a supplement to a range of strategies supporting the increasing number of people on the island. This explains why land use patterns continue relatively unchanged while livelihood and food supply strategies have changed.  相似文献   

19.
太湖流域土地利用变化对耕地生产力的影响研究   总被引：2，自引：1，他引：1  
以城镇化过程持续加速而耕地流失及粮食供需形势日趋严峻的太湖流域为研究区,结合遥感、土壤、气象及农业统计数据,借助AEZ模型和GIS开展1985~2010年土地利用变化对耕地生产力的影响分析及评价。结果表明：① 流域耕地生产力水平较高,高产耕地分布广泛;② 近30 a来就地城镇化和工业化发展导致流域建设用地快速扩张,耕地数量锐减;③ 由于减少的多为城市周边及交通沿线水土条件优越的优质耕地,新增的则多是来源于土地复垦或整理的低产耕地,“高产耕地锐减-低产耕地缓增”导致流域耕地生产力水平下降,且在不同发展阶段下降格局不同;④ 高产田锐减导致流域粮食大幅减产,不同县域由于经济发展水平和耕地利用条件不同,粮食减幅呈现显著空间差异。  相似文献   

20.
Crop diversity (e.g. the number of agricultural crop types and the level of evenness in area distribution) in the agricultural systems of arid Central Asia has recently been increased mainly to achieve food security of the rural population, however, not throughout the irrigation system. Site-specific factors that promote or hamper crop diversification after the dissolvent of the Soviet Union have hardly been assessed yet. While tapping the potential of remote sensing, the objective was to map and explain spatial patterns of current crop diversity by the example of the irrigated agricultural landscapes of the Fergana Valley, Uzbekistan. Multi-temporal Landsat and RapidEye satellite data formed the basis for creating annual and multi-annual crop maps for 2010–2012 while using supervised classifications. Applying the Simpson index of diversity (SID) to circular buffers with radii of 1.5 and 5 km elucidated the spatial distribution of crop diversity at both the local and landscape spatial scales. A variable importance analysis, rooted in the conditional forest algorithm, investigated potential environmental and socio-economic drivers of the spatial patterns of crop diversity. Overall accuracy of the annual crop maps ranged from 0.84 to 0.86 whilst the SID varied between 0.1 and 0.85. The findings confirmed the existence of areas under monocultures as well as of crop diverse patches. Higher crop diversity occurred in the more distal parts of the irrigation system and sparsely settled areas, especially due to orchards. In contrast, in water-secure and densely settled areas, cotton-wheat rotations dominated due to the state interventions in crop cultivation. Distances to irrigation infrastructure, settlements and the road network influenced crop diversity the most. Spatial explicit information on crop diversity per se has the potential to support policymaking and spatial planning towards crop diversification. Driver analysis as exemplified at the study region in Uzbekistan can help reaching the declared policy to increase crop diversity throughout the country and even beyond.  相似文献   

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