Spatial optimization of nutrient reduction measures on agricultural land to improve water quality: A coupled modeling approach

The objective of this study is to identify the optimal spatial distribution of Best Management Practices (BMPs) to reduce total phosphorus (TP) runoff from agricultural land in the largest Canadian watershed draining into Lake Erie, the Great Lake most vulnerable to eutrophication. BMP measures include reduced fertilizer application, cover crops, buffer strips, and the restoration of wetlands. Environmental SWAT model results feed into a spatial optimization procedure using two separate objective functions to distinguish between public BMP program implementation costs (PIC) on the one hand and farmers’ private pollution abatement costs (PAC) on the other hand. The latter account for the opportunity costs of land retirement and changing land productivity. PAC are initially lower than PIC but exceed the latter after 30% of the annual TP baseline load is eliminated. This suggests that under optimal conditions existing grant and incentive payments cover the economic costs farmers face up to a maximum of 30% of the baseline load reduction. Imposing further reductions of up to 40% results in a cost to farmers of almost $52 million per year. This is 45% higher than the optimal solution based on PIC and therefore not deemed incentive-compatible under the watershed's existing cost-sharing scheme.     

Economic development,food demand and the consequences for agricultural resource requirements: an application to Indonesia

We analyse food demand patterns of Indonesian households from a resource intensity perspective and quantify the impact of changed demand patterns on the use of three major resource inputs: fossil fuel; land; and water in agricultural production. Using Indonesian Family Life Survey data, 13 major food items (which constitute 70 per cent of food expenditure) are categorised into low, moderate and high resource intensity, and income elasticity and Engel curves are estimated for the period from 1997 to 2007. Our results show that income growth in Indonesia is associated with demand patterns that are more resource intensive. By 2007, per capita requirements of fossil fuel, land and water increased by 42.7 per cent (3.13 MJ), 44.9 per cent (1.24 m²) and 50.4 per cent (2.1 kL), respectively, relative to 1997. The results imply that, at least for Indonesia, changed food demand patterns resulting from economic development will increase the demand for natural resources substantially.     

新农科建设背景下农林经济管理专业仿真教学研究

新农科建设着力于系统培养农林经济管理专业学生的理论知识、实践能力、创新创业能力与综合素养。基于知识-能力-素养-个性的人才培养要求,结合农林经济管理专业人才培养目标与专业课程框架体系,阐释了农林经济管理专业仿真实训教学的课程属性、设计理念、功能框架、运行机制与应用价值。提出了农林经济管理专业人才培养目标、培养模式、教学手段的新要求与新思路。     

Projected impacts of increased uptake of source control mitigation measures on agricultural diffuse pollution emissions to water and air

A multi-pollutant modelling framework for England and Wales is described. This includes emissions of nitrate, phosphorus and sediment to water and ammonia, methane and nitrous oxide to air, and has been used to characterise baseline (no uptake of on-farm measures) and business-as-usual (BAU) annual pollutant losses, comparing these with the loss under a range of new policies aimed at increasing the uptake of relevant source control measures to 95% across England and Wales. Model outputs, including uncertainty ranges, evaluated using national water and air quality data layers have been summarised at both farm (Robust Farm Type) and water management catchment (WMC) scale. Nationally, across all farm types, the median annual reductions in pollutant losses under the new scenario, relative to BAU in 2010, were predicted to range between 9 and 16% for nitrate, 13–37% for phosphorus, 12–21% for sediment, 2–57% for methane and 10–17% for nitrous oxide. For ammonia, the range was −2–28%, indicating the potential for pollution swapping and an increase in ammonia emissions under scenarios designed to reduce nitrogen flux to waters. Increased uptake of pollution source control measures would result in a wide range of annual total (capital and operational) costs (per farm) for the major farm types, with median estimates ranging from £635 yr⁻¹ (Less Favourable Areas (LFA) with grazing livestock) to £15,492 yr⁻¹ (Cereals) in Nitrate Vulnerable Zone (NVZ) areas, compared with a range of £23 yr⁻¹ to £13,484 yr⁻¹ for the same respective farm types in non-NVZ areas. The estimated median annual load reductions for all WMCs relative to BAU, were predicted to be 16% for nitrate, 20% for phosphorus, 16% for sediment, 16% for ammonia, 15% for methane and 18% for nitrous oxide. These predictions suggest that almost perfect (95% uptake) implementation of source control measures will not deliver substantial improvements in pollutant emissions.     

退耕还林的经济学分析及其对策

从经济学的角度对退耕还林政策进行深入分析,探讨退耕还林过程中现行政策执行的内在偏差,并分析出导致执行出现偏差的主要原因在于退耕还林与退耕农户利益之间存在着一定的矛盾,即长远利益与当前利益、外部经济利益与农户利益间的矛盾。在此基础上,有针对性地提出进一步完善退耕还林政策的相关对策措施。     

Partial equilibrium analysis of vaccination as an avian influenza control tool in the U.S. poultry sector

The study addresses the economic effectiveness of vaccination in the case of highly pathogenic avian influenza (HPAI) outbreaks. The effectiveness is evaluated in a U.S. case study comparing the outbreak costs under the currently recommended HPAI control practice versus one which also includes vaccination. An integrated economic‐epidemic partial equilibrium model is used to empirically simulate HPAI outbreaks in three different poultry regions within the State of Texas. The simulation results show that the effectiveness of vaccination depends on flock density in the region and risk aversion preferences of the decision maker. In regions with high flock densities, if the decision maker is less risk averse the currently recommended strategy—which includes depopulation, movement restrictions, and flock testing—is more cost‐effective than the same strategy supplemented with vaccination. Addition of vaccination improves cost effectiveness only if the decision maker is highly risk averse or if surveillance, carcass disposal, and cleaning costs are high. In regions with medium and low flock densities, adding vaccination to the currently recommended strategy is not cost‐effective except in the case of high surveillance, carcass disposal, and cleaning costs.     

矿业参与宏观调控的经济法思考

矿业作为关系国计民生的重要经济和社会领域,矿产资源参与宏观经济调控应该是国土资源管理部门行使政府职能必须考虑的一个问题。从经济法律角度进行分析,可以得出当前我国矿产资源宏观调控法律规范滞后于资源可持续发展要求的结论。因此,应完善矿产资源规划、市场运行机制、价格税收、环境保护及利益分配等矿业领域的宏观调控法律规范,以促进和保障矿业可持续发展战略目标的实现。     

主成分分析法在油气开发方案技术经济评价中的应用

对油气产能建设性项目进行经济评价时,往往涉及到多个经济评价指标。为了突出反映项目可行性的重要指标,需要在损失一些次要信息的情况下,减少变量的个数,降到低维空间进行方案决策。在以主成分分析法讨论四川新场气田经济评价方案选择中的应用时,通过对样本的一些变换,确定样本的主成分及意义,求取综合主成分因子确定各个方案的综合经济评价指标,进一步选择最佳的实施方案。对方案Ⅵ和方案Ⅶ进行了敏感性分析,从另一个角度验证了方案Ⅵ和方案Ⅶ抗风险能力较强,证明采用主成分分析法选择方案的正确性。     

从利润指标的成因浅探提高经济运行质量的方法

按权责发生制要求核算的利润对当前实际经济运行质量的衡量存在一定的局限性 ,应收帐款坏帐的发生会导致企业已有的利润变为乌有。本文就是探讨一种如何从经济业务发生的起点开始寻找一种使坏帐最小的提高经济运行质量的方法。     

注重运用经济手段 确保国土资源参与宏观调控取得实效

中央明确要求 ,要继续加强和改善宏观调控 ,要发挥市场配置资源的基础作用 ,更加注意运用经济手段和法律手段。把运用经济手段放在突出地位是党中央深刻分析、总结宏观调控经验后做出的重要决断。总结国土资源参与宏观调控的经验 ,为确保国土资源参与宏观调控取得实效 :一要牢固树立用经济手段管理国土资源的意识 ;二要更加注重运用经济手段管理矿产资源 ;三要正确把握运用经济手段实施土地参与宏观调控的力度和重点     

建设用地扩张对经济增长的贡献及其区域差异研究

研究目的：应用1999 — 2007年分省数据,测度近年建设用地扩张对中国及不同区域经济增长的贡献及变化趋势,为土地政策制定提供依据。研究方法：效率评价法、多元回归分析法、比较分析法。研究结果：（1）1999 — 2007年中国固定资本、劳动力和建设用地的产出弹性分别为0.745、0.274和0.083;（2）初级产品阶段地区、工业化阶段地区、发达经济阶段地区建设用地的产出弹性分别为0.376、0.068和0.066;（3）地区技术效率和土地宏观调控对建设用地扩张存在显著抑制作用。研究结论：（1）建设用地扩张对经济增长的贡献随着发展阶段演进逐渐减小;（2）对处于不同发展阶段的地区,应实行差别化的土地管理策略与绩效考核方法。     

汉唐间北方农业技术的南传及在江南地区的本土化发展

中国传统的农业技术体系率先成熟于秦汉时期,是以北方旱作农业为基础所形成的,所以具有一定的地域性特征。汉唐间,伴随中央政权对江南地区的次第开发,传统农业技术的诸多元素也源源进入江南地区,催生了稻作农业技术体系的形成,对江南地区经济与社会发展产生了积极影响;回顾这一历史过程我们亦不难发现,源自于北方地区的传统农业技术不是立竿见影地在江南地区产生普遍影响,而是存在一个不断本土化的过程,至唐代,这一过程大体完成,因此也最终引发了江南经济的真正的繁荣。     

支农财政、技术进步偏向的农田利用碳排放效应研究

研究目的:识别农田利用方式转型期支农财政、农业技术进步偏向及其交互作用对农田利用碳排放的影响及其区域差异,评价支农财政和农业技术进步的环境效率,提出减排政策建议。研究方法:构建农田利用碳排放强度指标,通过估计核密度函数揭示其区域分布,基于加入交互项的固定效应模型实证检验核心变量对农田利用碳排放强度的影响效果。研究结果:单位播种面积农田利用碳排放均值逐年增加,区域差异扩大;单位产值农田利用碳排放均值逐年减小,区域差异缩小;支农财政倾向于提高农田利用碳排放强度,效果与种植结构相关;与资源禀赋耦合的农业技术进步偏向具有减排效应,并有利于降低支农财政的促排效果,该交互作用亦与种植结构相关。研究结论:支农财政政策应关注由其产生的环境压力,通过提高生产要素利用效率、推动与资源禀赋相耦合的农业技术进步等途径促进农田利用碳减排,充分考虑农作物种植结构的区域差异,提高政策的精准性。     

燕北暨西辽河流域史前经济形态及其演变态势

燕北暨西辽河流域是一个独具特色的生态文化区,该区已发现的考古学文化——兴隆洼文化、赵宝沟文化、红山文化、夏家店下层文化处于新石器中晚期至早期青铜阶段(史前时期)。研究表明,此间该文化区经济形态的内容和特征为:多种经济形态并存;渔猎经济居重要地位;本地是北方旱作农业的发源地,农业地位逐渐上升乃至成为主导性的经济活动方式。     

云南省2002-2008年土地利用变化及与社会经济发展关系

以云南省为研究区,以2002-2008年的土地利用变更调查和统计数据为基础,通过分析土地利用变化和社会经济发展关系,得出云南省各州、市之间的土地利用变化类型多样、差异显著,各具特点,土地利用的制约性因素较多,分布不均衡,土地利用变化同人口、人均生产总值等相关因素有着较大的关系,而同全社会固定资产投资和居民消费价格总指数的关联较小.应提高建设用地集约利用程度,加强土地用途管制,注重加强人口因素和经济因素对土地利用变化所能带来的积极作用.