关键词： Agricultural innovation systems   climate change   food security  

摘要： Climate change and variability present new challenges for agriculture, particularly for smallholder farmers who continue to be the mainstay of food production in developing countries. Recent global food crises have exposed the structural vulnerability of globalized agri-food systems, highlighting climate change as just one of a complex set of environmental, demographic, social and economic drivers generating instability and food insecurity, the impacts of which disproportionately affect poorer groups in marginal environments. Rather than search for single causes, there is a need to understand these changes at a systemic level. Improved understanding of and engagement with the adaptive strategies and innovations of communities living in conditions of rapid change provides an appropriate starting point for those seeking to shape agricultural innovation systems responsive to food insecurity and climate change. This paper draws lessons from selected country experiences of adaptation and innovation in pursuit of food security goals. It reviews three cases of systems of innovation operating in contrasting regional, socio-economic and agro-ecological contexts, in terms of four features of innovation systems more likely to build, sustain or enhance food security in situations of rapid change: (i) recognition of the multifunctionality of agriculture and opportunities to realize multiple benefits;(ii) access to diversity as the basis for flexibility and resilience;(iii) concern for enhancing capacity of decision makers at all levels;and (iv) continuity of effort aimed at securing the well-being of those who depend on agriculture. Finally, implications for policymakers and other stakeholders in agricultural innovation systems are presented.

关键词： soil respiration   spring barley   soil tillage   pasture   DNDC  

摘要： Simulation models can be valuable to investigate potential effects of climate change on greenhouse gas emissions from terrestrial ecosystems. DNDC (the DeNitrification-DeComposition model) was tested against observed soil respiration data from adjacent pasture and arable fields in the Irish midlands. The arable field was converted from grassland approximately 50 years ago and managed since 2003 under two different tillage systems;conventional and reduced tillage. Both fields were located on the same soil type, classified as a free draining sandy loam soil derived from fluvial glacial gravels with low soil moisture holding capacity. Soil respiration measurements were made from January 2003 to August 2005. Three climate scenarios were investigated, a baseline of measured climatic data from a weather station at the field site, and high and low temperature sensitivity scenarios predicted by the Community Climate Change Consortium for Ireland (C4I) based on the Hadley Centre Global Climate Model (HadCM(3)) and the Intergovernment Panel on Climate Change (IPCC) A1B emission scenario. The aims of this study were to use measured soil respiration rates to validate the DNDC model for estimating CO2 efflux from these key Irish soils, investigate the effects of future climate change on CO2 efflux and estimate the efflux uncertainties due to using different future climate projections. The results indicate that the DNDC model can reliably estimate soil respiration from the two fields examined. The model underestimated annual measured CO2 efflux from the pasture by only13% (model efficiency: ME = 0.6;root mean square error: RMSE = 1.9 and mean absolute error: MAE = 6.3) and that from the arable conventional and reduced tillage by 9% (ME = 0.6;RMSE = 1.6 and MAE = 2.4) and 8% (ME = 0.23;RMSE = 1.8 and MAE = 2.9), respectively. Short-term land use change had no significant effects on CO2 effluxes from soil. Using the high temperature sensitivity scenario, future C effluxes would inc

关键词： 气候变化   适应性措施   绩效评估   粮食产量   DID模型  

摘要： 本文基于对江苏省GEF项目区的调研,采用倍差法(D ifference inD ifference)对农业适应气候变化措施的绩效进行分析和评估。研究表明,GEF项目中农业适应气候变化措施的绩效集中体现在粮食产量上,适应性措施的实施显著地提高了项目区粮食单产水平,尤其是水稻的单产水平;适应性措施对水稻单产的净效应为42.41公斤/亩,对小麦单产的净效应为5.96公斤/亩。GEF项目的适应性措施体系可以为全国未来适应气候变化农业综合开发项目提供参考。

关键词： 全球气候变化背景   青藏高原   农业气候资源   气候倾向率  

摘要： 基于青藏高原干旱半干旱区1961—2007年55个气象站点地面观测资料,利用五日滑动平均法及GIS软件的IDW模块进行栅格处理,对比分析了研究区1961—1980年(时段Ⅰ)和1981—2007年(时段Ⅱ)各气候要素的时空变化特征及其气候倾向率.结果表明:1961—2007年,研究区喜凉作物生长季内日照时数的变化不明显,喜温作物生长季内日照时数呈增加趋势,但空间分布的变化较小;与时段Ⅰ相比,时段Ⅱ喜温作物生长季内积温值≥1500℃.d的地区面积扩大33.9%;降水量的空间分布总体表现为由东南低地向西北内陆逐渐递减,研究期间青藏高原东南部喜凉作物生长季内降水量均达到800 mm,其他地区喜凉作物生长季内降水量的气候倾向率有正有负,变幅相对较小,与时段Ⅰ相比,时段Ⅱ喜温作物生长季内降水量≥400 mm的分布面积扩大了40%;参考作物蒸散量(ET0)总体略有增加,其空间分布格局与日照时数和积温的分布相似,时段Ⅱ较时段Ⅰ喜温作物生长季内ET0≥400 mm的分布面积扩大了35.7%.研究期间,青藏高原作物生长季内的热量与降水资源有一定幅度增加,这对农牧业生产非常有利,但ET0的增大表明潜在蒸发增大,需进一步加强研究气候变化对该区域农牧业生产带来的可能影响.

关键词： 气候变化   农业   影响   对策  

摘要： 文章从近年来中国气候变化的事实和未来发展趋势入手进行分析,详细阐述了气候变化对农业生产的影响,包括对农业生产条件的影响和对农作物的影响,最后针对上述影响提出了农业开发应采取的措施。

摘要： As climate change has emerged as a significant threat, there is much concern about how vulnerable agricultural communities will adapt, particularly as global population continues to rise. Much of the current lack of productivity and economic marginalization of African agriculture arises from global trade regimes that give a competitive advantage to Western farmers, from low use of agricultural inputs, and from a dearth of infrastructure and services for the agriculture sector. For centuries, African farmers have used a wide variety of risk-reducing livelihood strategies, including diversifying income sources, switching crops, and investing in marketing. However, improving their productivity to “modern” levels has remained a distant dream, resulting in a continual reduction in investment in the sector over the past five decades.

摘要： The United States could manage the nation's forest and agricultural lands in ways that would sequester more carbon and reduce U.S. emissions of carbon, according to two reports issued by the Pew Center on Global Climate Change on 21 September. The reports recommend a national strategy that could include policies such as regulating land use of privately owned forests, incentives for farmers, and changing public land practices. According to the reports, U.S. greenhouse gas emissions could be offset by one fifth through changes in agricultural land practices and the foresting of marginal agricultural lands, and the use of biofuels could reduce emissions by another 10 to 25 percent.

关键词： 气候变化   农业生产   粮食安全   影响  

摘要： 在全球气候变化的大背景下,农业气候受其影响很大,综述了近几年来国内外学者专家对农业气候变化的研究工作及其进展,主要包括气候变化对农作物、粮食安全及整个农业的影响等内容。