首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Land conversion to urban use typically accompanies economic development but raises concerns about food security. Debates of these issues often rely on incomplete and incompatible evidence. This study uses satellite‐detected luminosity, from 1992 to 2012, to examine the urban land expansion of 41 major urban areas in Indonesia. The trend annual expansion rate is 2.0 per cent, which is comparable to the rate for India and just one‐third of the rate for China, as estimated with the same data and methods. Prior to the Asian Financial Crisis in 1997/98, the rate of urban expansion was faster, and the income elasticity of urban expansion was much higher. About 85 per cent of the area of urban expansion had formerly been grassland, shrub or woodland, and just 7.0 per cent was former cropland so food security concerns about urban expansion may be overstated.  相似文献   

2.
Rice is Indonesia's staple food and accounts for large shares of both consumers' budgets and total employment. Until recently, Indonesia was the world's largest importer, but rice import policy is now highly protectionist. Since early 2004, rice imports have been officially banned. Advocates of this policy say it reduces poverty by assisting poor farmers. Opponents say it increases poverty, stressing negative effects on poor consumers. This paper uses a general equilibrium model of the Indonesian economy to analyse the effects of a ban on rice imports. The analysis recognises 1000 individual households, including all major socioeconomic categories, disaggregated by expenditures per person. It takes account of effects on each household's real expenditure and its income, operating through wages and returns to land and capital. The results indicate that the rice import ban raises the domestic price of rice relative to the import price by an amount equivalent to a 125 per cent tariff, six times the pre‐2004 tariff. Poverty incidence rises by a little under 1 per cent of the population and increases in both rural and urban areas. Among farmers, only the richest gain. These results are qualitatively robust to variations in key parametric assumptions.  相似文献   

3.
Urban regions are important places of ecosystem service demands and, at the same time, are the primary source of global environmental impacts. Although there is broad agreement on the importance of incorporating the concept of ecosystem services into policy strategies and decision-making, the lack of a standardized approach to quantifying ecosystem services at the landscape scale has hindered progress in this direction. Moreover, tradeoffs between ecosystem services and the supply/demand ratio of ecosystem services in urban landscapes have rarely been investigated. In our paper, we present a method to quantify and map the supply and demand of three essential provisioning services - energy, food, and water - along the rural-urban gradient of the eastern German region Leipzig-Halle. This urban region has experienced significant socio-economic dynamics and land use changes since the German reunification in 1990. The results show that both the demand and the supply of ecosystem services changed considerably during the time span under consideration (1990-2007). We identified an increasing supply/demand ratio of food and water but a decreasing supply/demand ratio of energy. In addition, the pattern of ecosystem demands shows a levelling of rural-urban gradients, reflecting profound modifications of traditional rural-urban relationships. The changes of ecosystem service supply gradients are determined more by land use intensity, such as the intensification of agricultural production, than by land cover changes such as urban sprawl. The comparison of supply/demand ratios and rural-urban patterns of ecosystem services can help decision-makers in landscape management in striving for a sustainable balance between resource supply and demand.  相似文献   

4.
Agriculture is the largest type of land use in the UK, accounting for about 77 per cent of the total area, compared with an average 50 per cent for the EU27. But in common with most high-income countries, agriculture's contribution to UK GDP and employment is low, at about 0.5 and 1.8 per cent, respectively, although the regional importance of the sector (and its associated food and farming industries) varies considerably.Of the 17.5 million ha used for agriculture, about 28 per cent is allocated to crops, and 67 per cent is grassland. The grassland includes 4.4 million ha of sole-owned rough grazing and 1.1 million ha of common land in mainly upland “disadvantaged areas,” primarily used for beef and sheep production. This has a major influence on land use, especially in the northern and western parts of the UK.From the 1930s until the mid-1980s, UK policy promoted increases in agricultural productivity to feed the nation from its own resources. An array of income and production support measures encouraged intensive farming, including a relative switch to arable farming in eastern areas. Since the early-1990s, policies have sought simultaneously to make UK agriculture internationally competitive and environmentally benign. These policies, evident in the Agenda 2000 Reforms of the Common Agricultural Policy, point the way forward for the future. It is likely that a greater distinction will emerge between policies to protect natural resources and enhance the flow of non-market ecosystem services from rural land, and agriculture and food policies intended to encourage an appropriate proportion of national food requirements to be met from domestic sources.It seems likely that over the next 50 years, the UK's land area will be required to deliver an increasingly diverse range of private and public goods to meet growing human needs and aspirations. This will require a balance of policy-driven goals and market forces. It will also need a much improved understanding of the trade-offs between food production and environmental goals and of the institutional arrangements required to achieve a balance of economic, social and environmental outcomes.  相似文献   

5.
This study uses resource‐based measures to explore the evolution of China's demand and supply for food. China's dietary shift from plant to animal‐based foods, induced by its income growth, is likely to impose considerable pressure on agricultural resources. China's demand for food on this measure appears consistent with global trends, while China is an out‐performer on the supply side, producing much more food than its income level and land endowment would predict. China's current per capita income is in a range where consumption growth is high and in excess of production growth, but the gap between supply and demand is likely to diminish as population and per capita consumption growth decelerate. Continuing agricultural productivity growth and sustainable resource management will be important influences on the growth of China's future net import demand for food.  相似文献   

6.
Indonesia has set the target that by the year 2020 its emissions of greenhouse gases will be reduced by 26 per cent relative to business‐as‐usual conditions. This article analyses the effectiveness of a subsidy to the use of land in forestry as a means of achieving this goal. The analysis uses a general equilibrium model of the Indonesian economy characterised by explicit treatment of land use, disaggregated by industry and by region. The results of the analysis indicate that the subsidy cost of permanently reducing carbon emissions by 26 per cent is a little over US$1 per metric tonne of carbon emissions abated. This cost needs to be compared with that of alternative instruments and with the price of carbon that might be agreed under the proposed Reducing Emissions through Deforestation and Land Degradation (REDD) scheme, to be administered through the World Bank and the United Nations.  相似文献   

7.
This study computes the eco‐efficiency of high‐yielding variety (HYV) rice production by including an on‐farm environmental damage index (OFEDI) as an undesirable output using data envelopment analysis. It then identifies its determinants by applying an interval regression procedure on a sample of 317 farmers from north‐western Bangladesh. Results reveal that the mean level of the OFEDI‐adjusted production efficiency (i.e. eco‐efficiency) is 89 per cent, whereas ignoring OFEDI adjustment (i.e. with OFEDI = 0) reduces the mean level of efficiency to 69 per cent, implying that the production of undesirable output or on‐farm environmental damage induces an efficiency loss of 20 per cent with significant differences across regions. The proportion of farmers’ income from HYV rice agriculture, land ownership, extension services and socio‐environmental living standard are the significant determinants of improving eco‐efficiency. Policy implications include investments in extension services and land reform measures to increase land ownership, which will synergistically improve eco‐efficiency of HYV rice production in Bangladesh.  相似文献   

8.
基于生态足迹模型的河南省农业生态承载力动态评价   总被引:3,自引:0,他引:3  
[目的]河南省是农业大国,研究其农业生态承载力可持续性不仅对河南省乃至全国都有重要意义。[方法]将生态足迹模型应用于农业领域生态可持续发展分析,将河南省农业生物生产性土地面积划分为耕地、林地、草地、水域用地,分别计算农产品、林产品、水产品及畜牧产品人均生态足迹及承载力。[结果]河南省人均耕地生态足迹由2007年的1.491hm2/人上升至2016年的2.164hm2/人,增长率45.10%,而人均耕地承载力却未出现同步增长,生态赤字不断加大。(2)2007年河南省草地人均生态足迹为0.101hm2/人,2016年上升至0.132hm2/人,增长率3.1%;而人均草地承载力却出现下降,下降率达26.2%,处于不可持续发展状态。(3)2007—2016年河南省水域人均生态足迹和人均水域承载力均未有太大变化。相比于耕地、林地和草地,其水域的供求差距最大。降低水域供求矛盾,提高水域及水产品利用效率是关键。(4)在农、林、牧、渔业中,河南省林地的人均生态足迹是唯一呈下降趋势的产业,2007年人均林地生态足迹为0.052hm2/人,2016年下降为0.046hm2/人,下降比率为11.54%;林地的人均生态承载力也是在4个产业中唯一出现增长的产业,上升比率为27.90%,但仍处于不可持续状态。[结论]2011—2016年河南省农业生态承载力严重不足,耕地保护、草地的确权及保护、提高水域及水产品利用效率、继续退耕还林是关键。  相似文献   

9.
[目的]严守耕地红线、合理利用和保护耕地资源,保障国家粮食安全。[方法]文章采用最小人均耕地面积和耕地压力指数模型,分析了2007—2016年中原经济区耕地压力时序变化特征,引入重心转移模型和变异系数,探究耕地压力重心的空间分布及迁移特征,并基于粮食生产因素和社会经济因素双重视角,选取10个指标运用灰色关联分析法对影响中原经济区耕地压力变化的驱动因素进行研究。[结果]2007—2016年中原经济区耕地压力指数呈现阶段性特征,总体处于波动递减的趋势,各地级市耕地压力离散程度和空间差异不断拉大,空间分布不均衡,东西分化趋势显著;耕地压力重心从西北向东南方向迁移,在郑州市区域移动;选取的影响因素指标对耕地压力变化均有影响,关联度大小依次为人均GDP城市化水平农民收入产业结构化肥投入灌溉水平复种指数粮食单产量耕地质量人均耕地面积。[结论]社会经济因素对耕地压力影响显著,是影响耕地压力变动的主导因素。  相似文献   

10.
Many Asian countries are expected to undergo structural transformations in their economies and rapid urbanization over the next 25 years. The changes in tastes and lifestyles engendered by urban living are likely to have significant influences on food demand. Changes in marketing systems and occupational changes, closely linked with increasing GNP per capita, also may influence the demand for food. In this paper, estimates presented for Taiwan demonstrate that structural changes in food demand (as distinguished from changes due to income and price effects) have been significant factors driving the rapid changes in dietary patterns seen in East Asia over the past three decades. Because most previous demand studies have ignored the possible influence of structural shifts which are highly correlated with increases in per capita income over time, the effects of income on food demand have been overestimated.  相似文献   

11.
Changing dietary preferences and population growth in South Asia have resulted in increasing demand for wheat and maize, along side high and sustained demand for rice. In the highly productive northwestern Indo-Gangetic Plains of South Asia, farmers utilize groundwater irrigation to assure that at least two of these crops are sequenced on the same field within the same year. Such double cropping has had a significant and positive influence on regional agricultural productivity. But in the risk-prone and food insecure lower Eastern Indo-Gangetic Plains (EIGP), cropping is less intensive. During the dryer winter months, arable land is frequently fallowed or devoted to lower yielding rainfed legumes. Seeing opportunity to boost cereals production, particularly for rice, donors and land use policy makers have consequently reprioritized agricultural development investments in this impoverished region. Tapping groundwater for irrigation and intensified double cropping, however, is unlikely to be economically viable or environmentally sound in the EIGP. Constraints include saline shallow water tables and the prohibitively high installation and energetic extraction costs from deeper freshwater aquifers. The network of largely underutilized rivers and natural canals in the EIGP could conversely be tapped to provide less energetically and economically costly surface water irrigation (SWI). This approach is now championed by the Government of Bangladesh, which has requested USD 500 million from donors to implement land and water use policies to facilitate SWI and double cropping. Precise geospatial assessment of where freshwater flows are most prominent, or where viable fallow or low production intensity cropland is most common, however remains lacking. In response, we used remotely sensed data to identify agricultural land, detect the temporal availability of freshwater in rivers and canals, and assess crop production intensity over a three-year study period in a 33,750 km2 case study area in southwestern Bangladesh. We combined these data with georeferenced and temporally explicitly soil and water salinity information, in addition to relative elevation classifications, in order to examine the extent of winter fallows and low productivity rainfed cropland that could be irrigated by small-scale surface water pumps. Applying observations of irrigated crop sowing dates and yields from 510 wheat, 550 maize, and 553 rice farmers, we also modeled crop intensification production scenarios within the case study area. We conservatively estimate that at least 20,800 and 103,000 ha of fallow and rainfed cropland, respectively, could be brought into intensified double cropping using SWI. Scenario analysis indicates that if 25%–75% of the fallow or low-intensity land were converted to irrigated maize, national aggregate production could increase by 10–14% or 29–42%, respectively. Conversion to wheat would conversely boost national production by 9–10% or 26–31%. Irrigated rice is however unlikely to contribute >3%. In aggregate, these actions could generate between USD 36–108 million of revenue annually among farmers. Intensification therefore has important land use policy and food and income security implications, helping to rationalizei SWI investments. Crop choice, water resource allocation, and water governance will however remain crucial considerations for irrigation planners.  相似文献   

12.
Food consumption patterns are undergoing substantial change in many countries as economic development proceeds. The trend is a move away from traditional cereals towards higher-value and higher-protein foods. Explaining such changes only in terms of traditional economic variables can lead to biased estimates of income effects and perhaps biased projections of food demand. Household survey data from Indonesia are used to measure the importance of several socioeconomic variables in explaining differences in household food consumption patterns and nutrition. Household expenditure and the level of women's education are shown to be the most influential in this explanation.  相似文献   

13.
目的 通过分析耕地利用综合效率的时空格局及影响因素,为促进边境地区农业可持续发展及保障粮食安全提供理论基础。方法 文章通过构建耕地利用效率“投入—产出”指标体系,运用DEA模型、Malmquist指数模型及Tobit模型从动静两方面研究了中国陆地边境地区的耕地利用综合效率的时空格局变化及分区域影响因素。结果 (1)2008—2018年中国陆地边境地区耕地利用综合效率经历“小幅下降—快速上升—稳步上升”3个阶段,耕地利用综合效率高值区总体上呈“多点式”向“带片状”转变的态势,连片集聚度不断上升。(2)边境地区耕地利用全要素生产率指数(TFP)波动幅度较大,由2008—2014年的“倒V”型反转向2014—2018年的“V”型增长过渡。从全要素生产率指数结果来看,西南边境地区>西北边境地区>东北边境地区,这与各片区发展的资源禀赋、区域定位等差异有关。(3)东北边境地区耕地利用综合效率的显著性影响因素有农业机械总动力与农业劳动力,西北边境地区耕地利用综合效率的显著性影响因素有化肥施用量、种植结构调整、农业机械总动力,西南边境地区耕地利用综合效率影响因素为农村居民人均纯收入、乡村户数、农林水利事务支出、种植结构调整、农业劳动力。结论 边境地区耕地利用综合效率的主导影响因素存在明显的空间差异性,应因地制宜实施差异化的耕地利用管控政策,有效促进边境地区耕地利用综合效率的持续增长,维护边境地区的社会稳定与国家粮食安全。  相似文献   

14.
Agricultural price policy has a major impact on the input markets as well as the output markets and a model is developed to analyse the effects of changes in support levels on U.K. agricultural employment, earnings, investment and land prices. This paper describes the specification, estimation and evaluation of the model and simulates the effects of a one per cent increase in support prices. The main conclusions are that net investment would increase in the years following the rise by a maximum in the second year of £12m and by a cumulative total of £44m (representing an increase of about 0.4 per cent in the capital stock). Employment on the other hand, while rising at first, would subsequently fall to almost one per cent below its original level, and earnings of hired labour also fall slightly. Net farm income increases by around 10 per cent and this is capitalised into a similar increase in land values.  相似文献   

15.
Spikes in international food prices in 2007–2008 worsened poverty incidence in Indonesia, both rural and urban, but only by small amounts. The paper reaches this conclusion using a multisectoral and multihousehold general equilibrium model of the Indonesian economy. The negative effect on poor consumers, operating through their living costs, outweighed the positive effect on poor farmers, operating through their incomes. Indonesia's post‐2004 rice import restrictions shielded its internal rice market from the temporary world price increases, muting the increase in poverty. But it did this only by imposing large and permanent increases in both domestic rice prices and poverty incidence. Poverty incidence increased more among rural than urban people, even though higher agricultural prices mean higher incomes for many of the rural poor. Gains to poor farmers were outweighed by the losses incurred by the large number of rural poor who are net buyers of food, and the fact that food represents a large share of their total budgets, even larger on average than for the urban poor. The main beneficiaries of higher food prices are not the rural poor, but the owners of agricultural land and capital, many of whom are urban based.  相似文献   

16.
Historically, land use in Britain has been shaped by the environment's capacity to provide energy as well as food, water and shelter. Over the next decades, energy will again become a major driver in land cover change as we seek to capture the necessary energy to replace fossil fuels, reduce environmental damage and substitute for insecure supplies. Britain was one of the first places to exploit fossil fuels extensively, initially coal, and it has the potential to generate considerable amounts of renewable energy from tides, waves, the wind, biomass and sunlight. The UK Government's policy is to develop a suite of technologies that will provide a resilient supply without compromising its economy or its international commitments to environmental protection.This paper examines the three major terrestrial options for renewable energy and assesses each by successively filtering them for feasibility, achievability and practicality incorporating existing developments, designation and public opinion. Technology and opinion are dynamic, so the outputs need to be viewed as indicative of alternative scenarios rather than as fixed forecasts. Implications for changes in the energy supply infrastructure needed to match the new supply chains are highlighted.The demand for energy depends on the demographic profile (population size, age distribution, lifestyle and expectations) and on economic activity. Here total demand is predicted using the UK Energy Research Centre's Energy 2050 model, which uses linear programming to balance economics and environmental capacity by major demand sectors in five-year time steps. The core model often generates challenging results.  相似文献   

17.
水资源可持续承载力是区域可持续发展综合评价的重要指标。文章从重庆市水资源系统、社会经济系统及生态环境系统等3个方面考虑,选取24个水资源承载力影响因子建立了水资源可持续利用评价指标体系。基于三角白化权函数的灰色评估是灰色聚类分析法中划分对象类别的一种新方法,将这种方法应用于重庆市水资源可持续承载力评价中,把重庆市2000~2009年的水资源可持续承载力状况分成劣、差、中、良、优等5个灰类进行综合聚类评估。结果表明:(1)2000~2009年间,重庆市水资源可持续承载力总体上处于上升趋势,排列顺序为:2008200020092004200220032007200520062001;在2000年、2008年及2009年属于优灰类,2001年属于劣灰类,2002年、2003年、2004年及2007年属于良灰类,2006年属于差灰类,2005年属于中灰类;(2)基于三角白化权函数的灰色评估评价得出的结果比较客观,重庆市水资源可持续承载力对水资源子系统依赖程度较高,制约重庆市未来水资源可持续利用的主要因素在于年际间的干旱灾害,应引起相关部门的高度重视。  相似文献   

18.
The present study estimates the potential costs of land degradation (LD) in agriculture at the national scale in Italy during 2000–2006 and provides a medium-term scenario for 2015 based on changes in climate conditions and human pressure. According to the user cost approach, a depletion factor (S) to agricultural income has been derived from the observed changes in a composite index of land sensitivity to degradation. Based on S figures, the investigated area has been classified into five risk categories from ‘negligible’ to ‘high’. Surface land classified as ‘high LD risk’ increased slightly from 1.1 per cent in 2000 to 4.4 per cent in 2006 ranging from 2.9 to 8.6 per cent in 2015. Eleven indicators have been used to identify the socioeconomic conditions which possibly discriminate districts in ‘high’ and ‘low’ LD risk in agriculture. The gap in LD risk observed in 2000 between developed and disadvantaged regions in Italy reduced significantly in 2006. This suggests that agriculture is sensitive to LD in both economically marginal and affluent areas where climate and soil conditions are turning towards the worse. These results support strategies improving sustainable agriculture–environment relationships and protecting the soil resource base at the local scale.  相似文献   

19.
Land for food production is limited. We investigate how land demand for food develops as populations grow, diets change and agricultural practices become more intensive. The Philippines provide an excellent case: during the 20th century population grew tenfold implying similar increases in basic dietary needs. To quantify occurring changes, we link average dietary patterns to their arable land requirements. For this, we utilize data on population, dietary patterns and crop yields from 1910 to 2003. While average per capita food supply improved during the century, the amount of land required to feed a person declined, albeit not continuous: it was at about 2500 m2 in 1910, at 2000 m2 in 1960, at 1000 m2 in 1985, and did not change greatly since then. Accounting for population growth, this translates to a fourfold increase in total land required for food from 1910 to 2003. When investigating what drove the observed developments at national level, we find that in the first half of 20th century population growth was linked to increased land requirements, before strong increases in yields were enabling constant land requirements for about two decades. Recently, the combined effect of dietary change and population growth led again to increased land requirements for food. Different yield developments in individual crops caused shifts in the relative land requirements of different food items. Our findings suggest that developments in land requirements for food and underlying factors are often non-linear. Caution is warranted when discussing futures of global food supply, based on assumptions of linear or continuous trends.  相似文献   

20.
Agricultural land use is affected by government policies and leads to different consequences of regional sustainability. In this work, changes in cropping patterns including acreage, cropping locations and management-related environmental impacts were simulated under various policy scenarios for Quzhou County, China. This county is in China's major agricultural region, the North China Plain. Four dominant crop systems were categorized (winter wheat/summer maize, winter wheat/summer maize/spring maize, cotton, and vegetables) and analyzed, following two alternative policy scenarios that either prioritized government funding to subsidize crop production (“subsidy” scenario) or promoted advanced irrigation techniques (“technique” scenario). Input–output coefficients for all four crop systems were determined, mainly irrigation demand, yield, and price of produce, but other factors like a limited area of arable land and scarce regional water resources were also considered. For the simulation, a LINDO Inc. system was linked with the CLUE (Conversion of Land Use and its Effects) model. Temporal changes of crop systems were simulated with the LINDO system, whereas spatial dynamics of cropping patterns were simulated with the CLUE model, based on land suitability maps. The results show that crop patterns changed variably with time under the two scenarios, and water availability was the primary constraint on sustainability of land use. Under the subsidy scenario, winter wheat/summer maize/spring maize became dominant across the entire county, replacing other crop systems. In contrast, the vegetable system gradually occupied farmland surrounding the township under the technique scenario. The different policies produced opposite consequences for regional sustainability. Although a “subsidy” policy contributed to farmers’ income, it did not encourage water conservation for sustainable crop production, leading to land abandonment because of water shortage. In contrast, the “technique” policy partially cut direct financial benefits to farmers, but promoted water conservation and made a substantial contribution to agricultural sustainability.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号