隋唐五代时期园艺作物的培育与引进

隋唐五代时期是我国园艺业发展史上的重要时期。多种园艺作物培育成功并有为数不少的域外作物引进中土。这些新品种的花果、蔬菜、香料等，为我国园艺业增添了新的内容，丰富了人民生活。有的作物后来传到国外，为世界园艺提供了宝贵的种质资源。培育与引进的成功，则是与隋唐五代时期经济发展、气候条件适宜以及园艺技术提高等因素紧密相关的。     

农机服务规模经营对粮食生产效率的影响机理研究

依据2009—2019年全国31个省（自治区、直辖市）的省级面板数据,运用随机前沿分析方法和Tobit模型,考量农机服务规模经营对粮食生产效率的影响及其作用机理。结果显示：2009—2019年,中国粮食生产效率总体递增,但区域间发展不平衡;农机服务规模经营通过技术引入效应和劳动力替代效应提高粮食生产效率,其中,技术引入效应的发挥受限于农业研发支出水平及其增速,劳动力替代效应在农业劳动力成本高的区域发挥的影响效用更佳。鉴于此,应加快农业科技创新,发展粮食生产全程机械化服务,完善农机社会化服务体系。     

陕西特色农产品的品牌经营战略研究

陕西具有发展特色农业的良好条件，但由于受自然经济传统约束，广大农民缺乏市场经营意识和经营经验，加之缺乏有效的农业合作组织，缺少辐射带动能力强的龙头企业，导致特色农产品的品牌化经营程度低，现有特色农产品的品牌知名度和美誉度不高，市场影响力有限。要创建陕西特色农产品品牌，必须提高特色农产品的生产者、经营者和地方政府的市场意识、品牌意识，组织专业协会，发展龙头企业，完善特色农产品技术服务支持体系，推行标准化生产，加强产后商品化处理，建立和完善农产品品牌质量认证体系，加强对农产品品牌的宣传推广力度。     

产业结构变动中的粮食安全研究——江苏的案例

九十年代末 ,江苏产业结构发生很大的变化 ,农业在国民经济中的比重下降较快 ,同时 ,由于经济的快速发展 ,农地日益减少 ,人地矛盾日益尖锐 ,被人们普遍关心的粮食安全问题被提上了议事日程。本文主要分析江苏产业结构调整对粮食生产和粮食安全的影响 ,并探讨江苏在产业结构调整中保证粮食安全的对策。     

Economic Potential of Biomass Based Fuels for Greenhouse Gas Emission Mitigation

Use of biofuels diminishes fossil fuelcombustion thereby also reducing net greenhousegas emissions. However, subsidies are neededto make agricultural biofuel productioneconomically feasible. To explore the economicpotential of biofuels in a greenhouse gasmitigation market, we incorporate data onproduction and biofuel processing for thedesignated energy crops switchgrass, hybridpoplar, and willow in an U.S. AgriculturalSector Model along with data on traditionalcrop-livestock production and processing, andafforestation of cropland. Net emissioncoefficients on all included agriculturalpractices are estimated through crop growthsimulation models or taken from the literature. Potential emission mitigation policies ormarkets are simulated via hypothetical carbonprices. At each carbon price level, theAgricultural Sector Model computes the newmarket equilibrium, revealing agriculturalcommodity prices, regionally specificproduction, input use, and welfare levels,environmental impacts, and adoption ofalternative management practices such asbiofuel production. Results indicate no rolefor biofuels below carbon prices of $40 perton of carbon equivalent. At these incentivelevels, emission reductions via reduced soiltillage and afforestation are more costefficient. For carbon prices above $70,biofuels dominate all other agriculturalmitigation strategies.     

“入世”与中国农业和粮食的发展

中国“入世”后 ,农业和粮食业将面临一系列的机遇和挑战。文章在详尽地分析了各种机遇和挑战的基础上 ,就我国农业和粮食业的全面、创新发展提出了具体的政策建议。     

中国粮食期货市场的发展:困境、原因和未来的道路

目前，中国粮食期货市场规模小，交易品种少，市场交易量萎缩，在整个经济中的影响力较弱。这是受我国期货市场制度创新的动机、推动主体及外部环境制约的结果。今后，我们应从健全期货市场三级监管体制、培育套期保值主体、放宽对投资主体的限制，提高市场的流动性、增加粮食期货交易品种等方面入手，促进中国粮食期货市场的发展。     

Bioenergy Crop Production in the United States: Potential Quantities, Land Use Changes, and Economic Impacts on the Agricultural Sector

The U.S. Departments of Agriculture and Energyjointly analyzed the economic potential for,and impacts of, large-scale bioenergy cropproduction in the United States. Anagricultural sector model (POLYSYS) wasmodified to include three potential bioenergycrops (switchgrass, hybrid poplar, and willow). At farmgate prices of US $2.44/GJ, anestimated 17 million hectares of bioenergycrops, annually yielding 171 million dry Mg ofbiomass, could potentially be produced at aprofit greater than existing agricultural usesfor the land. The estimate assumes highproductivity management practices are permittedon Conservation Reserve Program lands. Traditional crops prices are estimated toincrease 9 to 14 percent above baseline pricesand farm income increases annually by US $6.0billion above baseline.At farmgate prices of US $1.83/GJ, anestimated 7.9 million hectares of bioenergycrops, annually yielding 55 million dry Mg ofbiomass, could potentially be produced at aprofit greater than existing agricultural usesfor the land. The estimate assumes managementpractices intended to achieve highenvironmental benefits on Conservation ReserveProgram lands. Traditional crops prices areestimated to increase 4 to 9 percent abovebaseline prices and farm income increasesannually by US $2.8 billion above baseline.     

论以粮换林换草与河西地区的可持续发展--以武威地区为例

分析了武威地区可持续发展的主要生态环境问题,讨论了生态恢复与重建面临的困境,论证了以粮换林换草对促进区域可持续发展的必要性和有效性,指出了以粮换林换草中应进一步研究的问题,提出生态重建要坚持多措施并举。