退耕还林对延安地区农业经济的影响

对延安地区11个农业县退耕前后耕地/播种总面积、种植业结构、农业投入、粮食、油料产量与单产量以及农民年均纯收入的变化进行了研究,探讨了退耕还林对延安地区农业经济的影响及其作用机制。退耕还林优化了农村的种植业结构与产业结构,全面带动了农村经济的发展。但仍然存在着一些亟待解决的问题,并给农村经济带来了一定的负面影响。     

基于SSBM-ESDA模型的安徽省县域农业效率时空演变

以绿色农业发展为导向,选择农业碳排放作为非期望产出指标,采用超效率的SSBM模型和探索性空间数据分析(ESDA)相结合的方法,以县域单元为尺度对2000-2017年安徽省农业效率水平、空间格局及其演变趋势进行实证分析。研究发现:①传统DEA模型忽视了农业碳排放等非期望产出的负面效应,从而高估农业资源利用的实际状态,基于超效率的SSBM模型更符合实际情况,能较好地识别各评价单元之间的优劣关系。②研究期内,安徽省农业效率值呈波动式上升态势,但总体上处于效率中等水平,农业效率空间分布不均衡,呈现出皖南地区>皖中地区>皖北地区的空间分布格局;空间变化趋势呈现自西向东递增、自北向南U型增长的变化态势,南北差异的增大是安徽省县(市、区)农业效率差异增大的主导因素。③除2010年外,安徽省农业效率呈正相关,空间差异有所缩小,但空间集聚程度相对较弱;安徽农业效率HH集聚县区集中分布于皖南地区,且呈现出向周边县区扩散的态势,LL型县(市、区)则主要分布在皖北地区,且空间分布较为稳定。④研究期内,安徽省农业效率空间正相关的县(区)数量有所增加,表明该时间段内安徽省农业效率空间上进一步集聚,LL型集聚的皖北地区应当是安徽省农业发展关注的重点。     

发展中国农业保险的对策分析

目前中国农业保险发展滞后,其原因主要有农民收入不高、农业保险保费收入低、农业保险的法律法规不够完善及农业保险组织体系不够健全,应提高农民收入、完善农业保险法律法规、建立健全农业保险组织体系,以促进中国农业保险业的发展。     

比较优势理论与农业区域专业化发展——以福建省为例

应用比较优势理论探讨农业区域专业化发展问题。理论推导得出,按照区域农产品生产优势来选建农业专业化部门能够实现农业增效,提高农业生产整体水平。以福建省为例,采用区位商和平均值法分析了主要农产品生产比较优势。结果表明,福建省多数县份的一种或几种农产品具有显著比较优势,农业生产的区域专业化已现端倪。但目前大多数县份主导产品不显著,专业化生产与农业资源禀赋不相协调。按照县域农产品的比较优势创建农业专业化部门,将是福建省解决"三农"问题和协调县域之间经济发展的有效途径。     

中国粮食生产区域分化特征和成因的实证研究

对中国在1990年和2002年粮食生产的区域分化状况进行统计分析的结果表明,工业化和城市化的发展,以及农产品市场形成条件下,稻米生产的区域分散特征、小麦生产的区域集中特征以及玉米播种面积的集中和生产产量的分散特征日益明显。计量检验显示,人均承包经营耕地面积和种植业收入比率是影响粮食生产区域分化的最主要的两个因素。     

非农化经营与农业上市公司经营绩效——理论分析与实证检验

我国农业上市公司非农化经营现象甚为严重,这一现象对农业上市公司经营绩效的影响引起了社会各界的广泛关注.农业上市公司非农化经营主要可以归纳为产业层次和企业管理层次这两方面成因.农业发展不足的现实成为我国农业上市公司非农化经营取向的最大产业背景因素.文章运用农业比较利益理论、外部性理论以及多元化经营理论,形成对农业上市公司非农化经营成因和非农化经营对绩效影响的理论分析框架.通过实证分析所得出的结论是:非农化经营从整体上减损了农业上市公司经营绩效.研究认为,政府应该着力在改善农业投资经营环境和制度创新上下功夫,才可能真正引导农业上市公司专注于农业上来;同时认为,目前农业上市公司主要应当实施农业专业化经营战略,在条件具备的情况下才实施与主业相关的多元化战略,现阶段应尽量避免非相关多元化经营.     

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.     

Impacts of an EC carbon/energy tax and deregulating thermal power supply on CO2, SO2 and NOx emissions

Emission of CO₂, SO₂ and NO_x are all closely linked to the burning of fossil fuels. Here we report on simulations done by linking a Sectoral European Energy Model (SEEM), covering energy demand in nine Western European countries, with the emission-transport-deposition model RAINS developed by IIASA. The study analyses emissions of CO₂, SO₂ and NO_x, deposition of sulphur and nitrogen and the extent of areas where the critical load for sulphur is exceeded in year 2000 under four different energy scenarios. Two different sets of future behavioural patterns for the thermal electric power production sector are considered. In one regime, called the plan-efficient regime, the sector is assumed to follow official plans with regard to investment in new capacity. In the other regime, called the cost-efficient regime, the thermal power sector is assumed to behave in a cost minimizing manner. The effects of the proposed EC carbon/energy tax are studied under both regimes, giving rise to altogether four scenarios.In both regimes the effect of the EC tax is to reduce emissions by between 6 and 10 per cent in year 2000 relative to the scenarios without the tax. A change of regime, from the regulated, plan-efficient regime to the market-based, cost-efficient regime, will, by itself, reduce emissions of CO₂ and NO_x by approximately 3 per cent, while SO₂ emissions are reduced by 13 per cent. The EC tax will reduce sulphur deposition by more than 5 per cent in the nine model countries under the plan-efficient regime. A change of regime further reduces the total deposition by 9 per cent. The area where depositions exceed the critical load is reduced by approximately 6 per cent in year 2000 by the tax in both regimes. Changing from the plan-efficient to the cost-efficient regime has a similar impact.Although the emission reductions due to the EC tax may seem modest, they are shown to have a sizeable effect on the technological abatement costs of reaching targets like those prescribed in the Sofia protocol on the stabilisation of NO_x emissions, and the Helsinki protocol on SO₂ emission reductions. This is part of what can be considered to be secondary benefits of the EC carbon/energy tax.     

城市森林固定CO2价值评估

本文利用我国第四次森林资源清样调查资料对上海市森林植被碳储量和碳密度的估算结果,结合植物的光合作用过程计算上海市森林固定CO2的能力,采用造林成本法对上海市森林固定CO2的价值进行了评估。笔者希望通过该研究激发人们保护城市森林以维持城市生态系统可持续发展的积极性,并为合理地进行城市森林管理和城市绿化提供参考。另外,利用系统连续的森林资源清样调查资料评估森林植被的固碳价值,能够对我国更好地履行《联合国气候变化框架公约(》UNFCCC),并为依据《京都议定书(》KyotoProtocol)进行环境外交提供帮助。     

黑龙江省农产品物流SWOT分析

近年来，随着农产品产量的增加和经营的放开，农产品物流环境发生了很大变化，不可控制因素变得更加复杂。本文通过对黑龙江省农产品物流现状进行SWOT分析．分别阐述了黑龙江省农产品物流的优势、劣势、机会、威胁等。指出只有完善农产品物流体系，抓好规模经营．提高组织化程度，才能更好地发展现代农业。