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1.
This paper examines possible adaptations to climate change in terms of pasture and crop land use and stocking rate in the United States (U.S.). Using Agricultural Census and climate data in a statistical model, we find that as temperature and precipitation increases agricultural commodity producers respond by reducing crop land and increasing pasture land. In addition, cattle stocking rate decreases as the summer Temperature-humidity Index (THI) increases and summer precipitation decreases. Using the statistical model with climate data from four General Circulation Models (GCMs), we project that land use shifts from cropping to grazing and the stocking rate declines, and these adaptations are more pronounced in the central and the southeast regions of the U.S. Controlling for other farm production variables, crop land decreases by 6 % and pasture land increases by 33 % from the baseline. Correspondingly, the associated economic impact due to adaptation is around ?14 and 29 million dollars to crop producers and pasture producers by the end of this century, respectively. The national and regional results have implications for farm programs and subsidy policies.  相似文献   

2.
The potential impacts of climate change on the phenology and yield of two maize varieties in Greece were studied. Three sites representing the central and northern agricultural regions were selected: Karditsa, Naoussa and Xanthi. The CERES-Maize model, embedded in the Decision Support System for Agrotechnology Transfer (DSSAT 3.0), was used for the crop simulations, with current and possible future management practices. Equilibrium doubled CO2 climate change scenarios were derived from the GISS, GFDL, and UKMO general circulation models (GCMs); a transient scenario was developed from the GISS GCM transient run A. These scenarios predict consistent increases in air temperature, small increases in solar radiation and precipitation changes that vary considerably over the study regions in Greece. Physiological effects of CO2 on crop growth and yield were simulated. Under present management practices, the climate change scenarios generally resulted in decreases in maize yield due to reduced duration of the growing period at all sites. Adaptation analyses showed that mitigation of climate change effects may be achieved through earlier sowing dates and the use of new maize varieties. Varieties with higher kernel-filling rates, currently restricted to the central regions, could be extended to the northern regions of Greece. In the central regions, new maize varieties with longer grain-filling periods might be needed.  相似文献   

3.
TheglobalclimatechangeandforestpredictioninChinaJiangYouxuForestryInstitute,ChineseAcademyofForestry,Beijing100091,ChinaThegl...  相似文献   

4.
Mapping and modelling of changes in agricultural intensity in Europe   总被引:1,自引:0,他引:1  
Spatial maps of agricultural intensity are needed for analyses of environmental issues, including biodiversity changes. We present a method to produce such maps for Europe. While most studies beyond farm level focus on land cover change only, this paper focuses on spatial variation in land use intensity and its dynamics.Our method defines agricultural land use intensity in terms of nitrogen input. For arable land, it combines field observations with administrative-level statistics to assess probability of occurrence for three land use intensity classes. For grassland, it uses maps of livestock density to assess probability of occurrence for two intensity classes. Agricultural land is spatially allocated to intensity classes using an algorithm that downscales intensity changes simulated with an agricultural economic model.Our results are 1 km2 resolution maps of classified agricultural land use intensity in the year 2000. We illustrate the method by exploring changes in the spatial pattern of land use intensity for a financial policy reform scenario in the year 2025. Results indicate spatial heterogeneity in land use intensity across European countries, including large differences in intensity between countries, between regions, but also within regions.Our method could be improved with smaller-resolution agricultural statistics and broader intensity indicators.  相似文献   

5.
Fresh water is one of the most important resources required for human existence, and ensuring its stable supply is a critical issue for sustainable development. The effects of a general set of agriculture and water management adaptations on the size of the world’s water-stressed population were assessed for a specific but consistent scenario on socio-economic development and climate change during the 21st century. To maintain consistency with agricultural land use change, we developed a grid-based water supply–demand model integrated with an agro-land use model and evaluated the water-stressed population using a water withdrawals-to-availability ratio for river basins. Our evaluation shows that, if no adaptation options are implemented, the world’s water-stressed population will increase from 1.8 billion in 2000 to about 3.3 billion in 2050, and then remain fairly constant. The population and economic growth rather than climate change will be dominant factors of this increase. Significant increase in the water-stressed population will occur in regions such as North Africa and the Middle East, India, Other South Asia, China and Southeast Asia. The key adaptation options differ by region, depending on dominant crops, increase in crop demand and so on. For instance, ‘improvement of irrigation efficiency’ and ‘enhancement of reclamation water’ seem to be one of important options to reduce the water stress in Southeast Asia, and North Africa and the Middle East, respectively. The worldwide implementation of adaptation options could decrease the water-stressed population by about 5 % and 7–17 %, relative to the scenario without adaptations, in 2050 and 2100, respectively.  相似文献   

6.
The Cameroonian agricultural sector, a critical part of the local ecosystem, is potentially vulnerable to climate change raising concerns about food security in the country’s future. Adaptations policies may be able to mitigate some of this vulnerability. This article investigates and addresses the issue of selected adaptation options within the context of Cameroonian food production. A methodology is applied where transient diagnostics of two atmosphere–ocean general circulation models, the NASA/Goddard Institute GISS and the British HadCM3, are coupled to a cropping system simulation model (CropSyst) to simulate current and future (2020, 2080) crop yields for selected key crops (bambara nut, groundnut, maize, sorghum, and soybean) in eight agricultural regions of Cameroon. Our results show that for the future, substantial yield increases are estimated for bambara groundnut, soybean and groundnut, while little or no change or even decreases for maize and sorghum yields, varying according to the climate scenario and the agricultural region investigated. Taking the “no regrets” principle into consideration, we explore the advantages of specific adaptation strategies specifically for three crops viz. maize, sorghum and bambara groundnut, under GISS A2 and B2 marker scenarios only. Changing sowing dates may be ineffective in counteracting adverse climatic effects because of the narrow rainfall band that strictly determines the timing of farm operations in Cameroon. In contrast, the possibility of developing later maturing new cultivars proved to be extremely effective in offsetting adverse impacts, giving the highest increases in productivity under different scenario projections without management changes. For example, under climate change scenario GISS A2 2080, a 14.6% reduction in maize yield was converted to a 32.1% increase; a 39.9% decrease in sorghum yield was converted to a 17.6% increase, and for bambara groundnut (an under-researched and underutilised African legume), yields were almost trebled (37.1% increase above that for sowing date alone (12.9%)) due to increase length of growing period and the positive effects of higher CO2 concentrations. These results may better inform wider studies and development strategies on sustainable agriculture in the area by providing an indication as to the potential direction in shifts in production capabilities. Our approach highlights the benefit of using models as tools to investigate potential climate change impacts, where results can supplement existing knowledge. The results provide useful guidance and motivation to public authorities and development agencies interested in food security issues in Cameroon and elsewhere.  相似文献   

7.
This paper examines the possible impact of climate change on Malaysian rice production. Using the Ricardian Method and farm household data, we have examined the effects on rice producers focusing on sharecropper adaptations and ecological causes. The principle goal of this research paper is to investigate the impact of climate variables such as temperature, rainfall and precipitation on rice production during main and off seasons, in Kedah, Malaysia. The main purpose of this paper is to examine how climate change affects the net income of paddy farmers in the study area. The statistically significant results show that temperature, rainfall, farm size, educational knowledge, land area and value of labour input have an impact on rice production per hectare revealing potential impacts of climate vulnerability on Malaysian agriculture. The results showed that net revenue increased by Ringgit Malaysia (RM 1= $0.3277) 4.78 per hectare throughout the main seasons as a result of minimal increase in the temperature while there is a decrease of RM 3.02 in the net revenue per hectare during off seasons. During the off season, rainfall increased revenue per hectare by RM 1.32 and during the main season it reduced revenue per hectare by RM 1.01. The evidence from this study may be useful for Malaysian policymakers to facilitate greater preventive measures during the main and off-seasons to counteract climate uncertainty and vulnerability.  相似文献   

8.
A vulnerability approach to climate change adaptation research is employed to explore prospects of agricultural adaptation to climatic variability and change. The methodological approach focuses on the system of concern, in this case, farms in Perth County, Ontario. Twenty-five interviews and four focus groups with farmers were used to identify climate risks on farms, and to document farmers’ responses to conditions and risks associated with climate and weather. The information collected describes a complex decision-making environment, with many forces both external and internal to the farm operation influencing management decisions. Within this environment, climate and weather are consistently referred to as a significant force influencing both farm operations and management decisions. Farmers have, however, developed a wide-range of anticipatory and reactive management strategies to manage climate risks. While these have potential to address future climate-related risks and opportunities, there are limits to adaptation, and an increase in the frequency of extreme events may exceed their adaptive capacities. Farmers are also generally unaware and/or unconcerned about future climate change, which could constrain opportunities to adopt long-term climate change adaptations.  相似文献   

9.
农户层面土地利用变化研究综述   总被引:24,自引:4,他引:20  
论文从研究视角、研究内容、研究方法和手段、数据获取4 个方面对农户层面土地利用变化 研究进行了概括。并归纳出目前研究的几个特点: ①研究较为关注热点地区; ②多将农户层面土地 利用变化的驱动力归因于人口增长所导致的生计压力以及与之相关的农业扩张; ③研究逐步从单 纯关注用途变更转向对用途变更和土地利用集约度变化并重; ④在手段和方法上趋于多样化并趋 向于综合使用多种方法; ⑤土地利用主体决策行为对于土地利用变化影响得到重视; ⑥在分析数据 的获取上, 问卷调查成为主导方式, 但越来越多的研究开始尝试将问卷调查和“3S”技术相结合。最 后总结了已有研究存在的问题, 并探讨了今后农户层面土地利用变化研究发展的方向。  相似文献   

10.
Future climate change directly impacts crop agriculture by altering temperature and precipitation regimes, crop yields, crop enterprise net returns, and net farm income. Most previous studies assess the potential impacts of agricultural adaptation to climate change on crop yields. This study attempts to evaluate the potential impacts of crop producers’ adaptation to future climate change on crop yield, crop enterprise net returns, and net farm income in Flathead Valley, Montana, USA. Crop enterprises refer to the combinations of inputs (e.g., land, labor, and capital) and field operations used to produce a crop. Two crop enterprise adaptations are evaluated: flexible scheduling of field operations; and crop irrigation. All crop yields are simulated using the Environmental Policy Integrated Climate (EPIC) model. Net farm income is assessed for small and large representative farms and two soils in the study area. Results show that average crop yields in the future period (2006–2050) without adaptation are between 7% and 48% lower than in the historical period (1960–2005). Flexible scheduling of the operations used in crop enterprises does not appear to be an economically efficient form of crop enterprise adaptation because it does not improve crop yields and crop enterprise net returns in the future period. With irrigation, crop yields are generally higher for all crop enterprises and crop enterprise net returns increase for the canola and alfalfa enterprises but decrease for all other assessed crop enterprises relative to no adaptation. Overall, average crop enterprise net return in the future period is 45% lower with than without irrigation. Net farm income decreases for both the large and small representative farms with both flexible scheduling and irrigation. Results indicate that flexible scheduling and irrigation adaptation are unlikely to reduce the potential adverse economic impacts of climate change on crop producers in Montana’s Flathead Valley.  相似文献   

11.
在江苏省苏州市、南京市、扬州市各自选择了2个村的基础上,运用对240个农户的抽样调查资料,建立了区域农业土地利用变化分析的数量经济模型,较为深入地分析了农村土地流转市场引导下的农户行为对于农业土地利用变化的影响。研究结果表明,在农户决策行为起主导作用的前提下,农业土地利用正在逐步由传统的大田作物向效益更高的经济作物和水产养殖等地类转化;农户家庭非农就业水平的提高有效地推进了这一转化;同时,农户受教育水平的高低以及政府行为都在一定程度上影响着农业土地利用变化。最后从区域非农产业和城镇化发展、深化农村土地产权的物权化改革、农村社会保障制度的完善、建立农村土地流转中介机制、进一步规范政府行为及积极推进农村户籍制度改革等方面提出了一些政策性建议。  相似文献   

12.
This study combined uncertainty analysis of carbon emissions with local stakeholders' perspectives to develop an effective Reducing Emission from Deforestation and Degradation (REDD+) scheme at the district level. Uncertainty of carbon emission estimates depends on scale while local stakeholders' views on plausible REDD+ schemes influence and limit transaction costs. The uncertainty analysis formed the basis for determining an appropriate scale for monitoring carbon emission estimates as performance measures for REDD+ incentives. Our analysis of stakeholder’ perspectives explored (i) potential location and activities for lower emission development pathways, and (ii) perceived fair allocation of REDD+incentives. Our case study focused on frontier forest in Tanjung Jabung Barat District, Jambi, Indonesia. The uncertainty analysis used Monte Carlo simulation techniques using known inaccuracy of land cover classification and variation in carbon stocks assessment per land cover type. With decreasing spatial resolution of carbon emission maps, uncertainty in carbon estimates decreased. At 1 km2 resolution uncertainty dropped below 5 %, retaining most of the coarser spatial variation in the district. Fairness, efficiency and transaction cost issues in the design of REDD+ mechanisms were readily recognized by local stakeholders, who converged on an equal allocation to short-term efficiency (emission reduction activities) and long-term fairness (alternative livelihood development). A striking difference occurred in desirable transaction costs (which include monitoring, reporting and verification), with Non-Governmental Organizations (NGOs) aiming for 8 %, while government and researchers accepted transaction costs of 40 %. Feasible measures for emission reduction in the district, derived from a participatory planning process, are compatible with the 1 km2 spatial resolution of performance measures.  相似文献   

13.
Climate change is expected to adversely affect agricultural production in Africa. Because agricultural production remains the main source of income for most rural communities in the region, adaptation of the agricultural sector is imperative to protect the livelihoods of the poor and to ensure food security. A better understanding of farmers’ perceptions of climate change, ongoing adaptation measures, and the decision-making process is important to inform policies aimed at promoting successful adaptation strategies for the agricultural sector. Using data from a survey of 1800 farm households in South Africa and Ethiopia, this study presents the adaptation strategies used by farmers in both countries and analyzes the factors influencing the decision to adapt. We find that the most common adaptation strategies include: use of different crops or crop varieties, planting trees, soil conservation, changing planting dates, and irrigation. However, despite having perceived changes in temperature and rainfall, a large percentage of farmers did not make any adjustments to their farming practices. The main barriers to adaptation cited by farmers were lack of access to credit in South Africa and lack of access to land, information, and credit in Ethiopia. A probit model is used to examine the factors influencing farmers’ decision to adapt to perceived climate changes. Factors influencing farmers’ decision to adapt include wealth, and access to extension, credit, and climate information in Ethiopia; and wealth, government farm support, and access to fertile land and credit in South Africa. Using a pooled dataset, an analysis of the factors affecting the decision to adapt to perceived climate change across both countries reveals that farmers were more likely to adapt if they had access to extension, credit, and land. Food aid, extension services, and information on climate change were found to facilitate adaptation among the poorest farmers. We conclude that policy-makers must create an enabling environment to support adaptation by increasing access to information, credit and markets, and make a particular effort to reach small-scale subsistence farmers, with limited resources to confront climate change.  相似文献   

14.
涪江流域农业非点源污染空间分布及污染源识别   总被引:18,自引:7,他引:11  
丁晓雯  沈珍瑶 《环境科学》2012,33(11):4025-4032
采用输出系数模型,借助地理信息系统技术,对涪江流域的农业非点源污染进行了模拟,分析了流域非点源污染的空间分布特征,并对主要污染源进行了辨识,以期为流域非点源污染控制与管理提供决策支持.研究表明,2010年研究区农业非点源总氮污染负荷为9.11×104t,全区平均负荷强度为3.10 t.km-2;农业非点源总氮负荷总量最主要分布在旱地、绵阳市和缓坡区,农业非点源总氮负荷强度的高负荷区为旱地、德阳市和缓坡区;农业用地的化肥流失是污染的首要污染源,贡献率为62.12%,其中旱地的化肥流失是最主要来源,贡献率为50.49%.可见,改进粗放的农业耕作方式、积极推进"退耕还林"、合理处理养殖废水、集中收集农村生活污水等是研究区非点源污染有效的控制措施.  相似文献   

15.
To propose specific adaptation strategies in the agricultural sector based on vulnerability to climate variability and climate change at the local level, we built a vulnerability index using an indicator tool at a fine spatial scale. This index was applied as a case study in the municipality of Guasave, Sinaloa, Mexico, at the basic census area (BCA) level. We used a total of 37 variables organized into three groups with equal weighting: exposure (13), sensitivity (13), and adaptive capacity (11). From the 20 rural BCAs located in the study area, eight were categorized as having very low vulnerability; five had low vulnerability; two had medium vulnerability because of the lack of basic services (sewers, water, and electricity) and a high rural population density; three had high vulnerability due to a high frequency of days with temperatures below 5 °C and the lack of basic services; and two had very high vulnerability, characterized by a high percentage of production units (PUs) with losses due to climate factors, a high rural population density, and a high frequency of days with temperatures below 5 °C. Approximately 50 % of the municipal rural population lives in BCAs vulnerable to climate change. This methodology allowed us to identify the most susceptible agricultural areas at the local level and the variables that require more attention so that we can propose adaptation strategies and minimize vulnerability due to climate change.  相似文献   

16.
湖北省农地资源价值研究   总被引:22,自引:0,他引:22  
农地价值包括农地提供粮食、纤维等农副产品可计量的市场价值和提供开敞空间、维护生物多样性、保育环境、文化教育等公共物品所具有的非市场价值。科学、合理地评估农地价值,形成完整的资源成本核算体系,可缓解我国农地流失形势,为制定和实施农地生态管护政策等提供理论与实践依据。文章运用收益还原法及条件价值评估法对湖北省不同类型农地的市场价值和非市场价值进行评估,较为科学地评估出农地的整体价值,摸清农地资源的价值构成。研究表明,湖北省包括耕地、园地、林地及水域用地在内的农地资源的非市场价值现值达2514.88×108元,相当于全省2004年生产总值的39.86%,是农地价值构成中无法忽略的重要部分。全省现有耕地资源总价值达11398.77×108元,目前无法进入交易市场或有效地通过交易机制实现的非市场价值有942.63×108元,占耕地总价值的8.27%;园地及水域用地的总价值分别为3715.27×108元和10192.81×108元,非市场价值的比例份额分别达13.64%和5.48%;现有林地资源的非市场价值达506.35×108元,折合林地非市场价值约6407元/hm2。  相似文献   

17.
The production of tropical agricultural commodities, such as cocoa (Theobroma cacao) and coffee (Coffea spp.), the countries and communities engaged in it, and the industries dependent on these commodities, are vulnerable to climate change. This is especially so where a large percentage of the global supply is grown in a single geographical region. Fortunately, there is often considerable spatial heterogeneity in the vulnerability to climate change within affected regions, implying that local production losses could be compensated through intensification and expansion of production elsewhere. However, this requires that site-level actions are integrated into a regional approach to climate change adaptation. We discuss here such a regional approach for cocoa in West Africa, where 70 % of global cocoa supply originates. On the basis of a statistical model of relative climatic suitability calibrated on West African cocoa farming areas and average climate projections for the 2030s and 2050s of, respectively, 15 and 19 Global Circulation Models, we divide the region into three adaptation zones: (i) a little affected zone permitting intensification and/or expansion of cocoa farming; (ii) a moderately affected zone requiring diversification and agronomic adjustments of farming practices; and (iii) a severely affected zone with need for progressive crop change. We argue that for tropical agricultural commodities, larger-scale adaptation planning that attempts to balance production trends across countries and regions could help reduce negative impacts of climate change on regional economies and global commodity supplies, despite the institutional challenges that this integration may pose.  相似文献   

18.
Reducing carbon emissions from deforestation and degradation in developing countries is of the central importance in efforts to combat climate change. A study was conducted to measure carbon stocks in various land-use systems including forms and reliably estimates the impact of land use on carbon (C) stocks in the forest of Rajasthan, western India (23°3′–30°12′N longitude and 69°30′–78°17′E). 22.8% of India is forested and 0.04% is the deforestation rate of India. In Indian forest sector of western India of Aravally mountain range covered large area of deciduous forest and it’s very helpful in carbon sequestration at global level. The carbon stocks of forest, plantation (reforestation) and agricultural land in aboveground, soil organic and fine root within forest were estimated through field data collection. Results revealed that the amount of total carbon stock of forests (533.64?±?37.54 Mg·ha?1, simplified expression of Mg (carbon) ·ha?1) was significantly greater (P?<?0.05) than the plantation (324.37?±?15.0 Mg·ha?1) and the agricultural land (120.50?±?2.17 Mg·ha?1). Soil organic carbon in the forests (172.84?±?3.78 Mg·ha?1) was also significantly greater (P?<?0.05) than the plantation (153.20?±?7.48 Mg·ha?1) and the agricultural land (108.71?±?1.68 Mg·ha?1). The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 30-cm layer and decreased with soil depth. The aboveground carbon (ABGC): soil organic carbon (SOC): fine root carbon ratios (FRC), was 8:4:1, 4:5:1, and 3:37:1 for the forest, plantation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land.  相似文献   

19.
刘玉  蒋治  王浩森 《自然资源学报》2020,35(10):2444-2459
北京减量提质发展背景下,农业地域功能主要体现在优质农产品生产、生态保护、高端休闲娱乐供给、新业态示范、产业链拓展与融合以及就业收入拉动等方面。以184个街道、乡镇为基本研究地域单元,测算了北京农业地域功能并剖析了空间分异特征。研究发现:北京农业地域功能空间分异与城市空间开发结构密切相关,总体上表现为自城乡结合部核心区、拓展区到远郊区呈圈层递增态势;城乡结合部拓展区农业地域功能衰退趋势显著,对城市空间开发的约束变弱;远郊区农产品供给、生态保护和就业安置等基本和传统功能较强而产业融合、新业态等高级与现代功能偏低,农业地域功能仍有较大提升空间。通过OLS基本回归和分位数回归发现,土地因素是影响北京农业地域功能的关键因素,其中区位因素决定农用地规模进而影响农业地域功能,房价因素通过加速农用地流转对功能最弱地区的农业地域功能具有明显抑制作用。非农产业对农业地域功能具有促进而非挤压替代作用。  相似文献   

20.
耕地地块细碎程度及其对山区农业生产成本的影响   总被引:6,自引:0,他引:6  
在务农成本持续上涨和省工性技术普及的背景下,山区地块细碎化逐渐成为抑制农民增收的重要因素。厘清山区耕地细碎程度及其对农业生产的影响,对于降低农业生产成本具有指导价值。基于重庆市武隆区、巫山县和酉阳县的1015份农户调研数据,分别从地块权属和空间分布两个角度测算耕地细碎程度,并采用半对数经济计量模型评估耕地细碎差异对农业生产成本的影响。结果表明:研究区耕地细碎程度严重,辛普森指数和地块距离指数分别为0.71和0.19,户均耕地面积6.19亩、地块数8.89块,地块与家庭平均相距430 m,即呈现出“块数多、规模小和距离短”的特征;耕地细碎程度加剧提高了农业生产成本,当辛普森指数和地块距离指数每增加一个标准差时,单位产量总成本依次上升33.8%和16.6%;具体到各单项成本,耕地细碎程度加剧显著提高了劳动力、化肥和种子成本,而限制机械及其他要素的使用。分作物的实证显示,耕地细碎化效应存在明显的作物异质性。此外,优质耕地能缓解地块细碎带来的成本上升,同时扩大地块面积有助于降低生产成本。政策启示:降低农业经营成本是缓解山区耕地撂荒的重要举措,政府应建立低成本的农地流转网络,并鼓励农户或村庄之间的土地互换,提高地块规模和减少耕作距离,同时政府还应推广和普及适合山区农业的微耕机械。  相似文献   

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