农业生产资料投入对粮食作物产出影响因素的相关验证分析

农业生产资料价格上涨,导致农民对农业生产的资源配置、作物结构以及投入结构进行调整,以优化生产成本,这将进一步影响相关粮食作物的产出。应用C—D生产函数的扩展形式,分析农业生产资料各投入要素变化,对粮食作物产出的影响程度。化肥施用量和农业劳动力数是影响粮食产出的两个主要因素,进而提出了推广科学施肥,提高化肥利用率、大力推广农业机械化技术的应用、加大国家对农业基础建设和科研开发与推广的投资力度等保障措施,来进一步促进粮食生产稳步增长。     

Genetically Modified Crops: Their Market and Welfare Impacts

A framework is developed for examining price and welfare effects of the introduction of genetically modified (GM) products. In the short run, non-GM grain generally becomes another identity-preserved product. However, more profound market effects are observed under some reasonable parameterizations. When calibrated to reflect the U.S. corn market, introducing GM technology increases aggregate welfare over a wide range of scenarios, unless the corresponding production cost savings are small and consumers are seriously concerned about GM products. The possibility that GM technology may reduce aggregate welfare is interesting because the model assumes rational agents and does not include regulatory constraints.     

Cash cropping and food crop productivity: synergies or trade‐offs?

The case for promoting export‐oriented cash crops in Africa has generally been based on their direct potential contribution to agricultural productivity and small farmer incomes. A relatively neglected avenue of research concerns the synergistic effects that cash cropping can have on other household activities, including food production. The conventional view that cash crops compete with food crops for land and labour neglects the potential for cash crop schemes to make available inputs on credit, management training, and other resources that can contribute to food crop productivity, which might otherwise not be accessible to farmers if they did not participate in cash crop programs. This article builds on previous research by hypothesising key pathways by which cash crops may affect food crop activities and empirically measuring these effects using the case of cotton in Gokwe North District in Zimbabwe. Analysis is based on instrumental variable analysis of survey data on 430 rural households in 1996. Results indicate that—after controlling for household assets, education and locational differences—households engaging intensively in cotton production obtain higher grain yields than non‐cotton and marginal cotton producers. We also find evidence of regional spill‐over effects whereby commercialisation schemes induce second round investments in a particular area that provide benefits to all farmers in that region, regardless of whether they engage in that commercialisation scheme. The study suggests that the potential spill‐over benefits for food crops through participation in cash crop programs are important to consider in the development of strategies designed to intensify African food crop production.     

我国农作物秸秆资源化利用的经济分析:一个理论框架

农作物秸秆是生物质资源的主要来源之一,与之相关的技术开发目前已成为生态农业和可持续发展的一个重大课题。农作物秸秆资源化利用有肥料、燃料、饲料、工业原料和食用菌基料等多种途径和技术路径,这些利用方式和技术的经济可行性如何,引起了研究者越来越多的关注。文章提供了一个对我国农作物秸秆资源化利用行为进行经济分析的理论框架。在该框架中,农作物秸秆资源化利用的总收益包括秸秆产品的市场价值、秸秆资源使用节约的相关资源性产品价值以及秸秆产品使用产生的环境收益;农作物秸秆资源化利用的总成本则由秸秆的收集、运输、储藏、加工以及机会成本构成。最后,文章对农作物秸秆资源化利用的公共政策等问题进行讨论。     

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。     

Testing assumptions underlying economic research on transgenic food crops for Third World farmers: Evidence from Cuba, Guatemala and Mexico

Transgenic crop varieties (TGVs) are being promoted as essential for improving small-scale Third World (SSTW) agriculture. Most economic research on this topic makes critical, untested assumptions, including that farmers will choose TGVs over other varieties because TGVs are economically optimal and because farmers are risk neutral profit maximizers. We tested these assumptions using data from a survey of 334 farmers in 6 communities in Cuba, Guatemala and Mexico in which farmers ranked 4 real and hypothetical maize varieties for eating and sowing. Our results did not support these assumptions. Most farmers preferred farmer varieties for sowing and especially for eating, avoiding TGVs, a preference associated with being risk averse and with non-monetary preferences. Farmers more integrated into modern agriculture were more likely to choose TGVs. These results suggest that farmers most in need of support and most important for conserving genetic diversity are least favorable toward TGVs, and that alternative ways of improving SSTW agriculture should receive more attention.     

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.     

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.     

Refining the debate on GM crops using technological foresight—the Danish experience

Rapid developments in and the controversial nature of biotechnology call for communication, networks, partnerships, and collaboration in research, not just among researchers, but also between researchers and research “users” in industry, government, and elsewhere. Technological foresight appears to offer a coordinating method for developing and strengthening those linkages. To test this, a technological foresight study was performed on genetically modified (GM) crop technology in the Danish context. The background of the study was the conflict and intense debate in Denmark over applications of gene technology, especially over the deliberate release of genetically modified (GM) crops. However, the current debate characteristically involves sharply opposed fronts, lacking willingness and courage to engage in a free-flowing and open-minded debate on both rational and normative components of biosafety. In it, stakeholders and experts on both side of the conflict advocate widely differing opinions. Without a proper generally intelligible dialogue, the broader public audience finds it hard to comprehend this type of debate. The study pursues the notion that public dialogue can act as a driver of future applications in the technological domain, specifically GM crops. The study concluded with a stakeholder workshop that revealed three key issues that might provide helpful starting points for a more free-flowing and open-minded debate about the future of GM crops. The issues were those arising from the following statements: a broad perspective on risk is crucial; international regulation must make allowance for developing countries; a better configuration of the risk debate is needed. These issues are discussed in more details in the article.     

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。