Trade Reform and the Corn Market: Prospects for the World Trade Organization Negotiations on Agriculture

Government support and trade restrictions on agricultural commodities are among the most globally distorting protectionist policies. This is especially true with regards to corn. Vast production subsidies and import barriers, primarily within the European Union and China, have artificially inflated the global supply of this commodity, while restricting the available consumer markets. This impact is augmented by the preferential treatment granted in these countries to the production and importation of the best available substitute to corn, soybeans. Using an econometric model with commodity data over the past 20 years, this article predicts the likely impact of potential World Trade Organization (WTO) trade pacts on these corn trade distortions. Despite the WTO setback in Seattle, the vast global benefits resulting from agricultural trade liberalization in corn alone validate a continued push towards freer trade.     

农业政策调整下大豆种植格局变化对水土资源消耗的影响评估

[目的]通过对政策调整下农作物种植格局变化引起的水土资源消耗变化研究,从资源利用角度为种植格局调整的政策制定提供科学支撑。[方法]文章以黑龙江省为研究区,利用系统动力学方法构建大豆种植格局驱动机制模型,并模拟三大作物(即大豆、玉米和水稻)补贴政策情景下的作物种植面积转换;其次,核算三大作物生产中的水土资源消耗量,并获取不同政策情景下大豆与玉米和水稻种植面积转换引起的水土资源消耗变化量。[结果](1)黑龙江省大豆、玉米和水稻生产过程中单位面积的水资源消耗排序为“大豆<玉米<水稻”,单位产量的耕地资源消耗排序为“水稻<玉米<大豆”。(2)由于单位面积大豆的耗水量最少、单位产量大豆的耕地消耗量最多,当大豆生产者补贴增加40%时,大豆净增加面积最多(由玉米和水稻转入),因此三大作物生产过程中水资源消耗总量减少最多为2 400万m³,但耕地资源消耗仅增加3.2万hm²。[结论]农业补贴调整,不仅可以满足粮食的总体供给,优化作物种植格局、扩大大豆种植面积,进而减少大豆供给的不确定性,还可以实现区域水土资源的优化配置。该文结论可以为...     

Production technologies in Ethiopian agriculture

This article examines the characteristics of and choice among two production technologies in Ethiopian agriculture, one with fertilizer and the other without, using 1989–90 farm-level data. For northwest and central Ethiopia, fertilizer usage determinants are estimated simultaneously with technology-specific production functions. For southern Ethiopia, where fertilizer is rarely used, a single production function is estimated. Three conclusions emerge. First, fertilizer use is not significantly affected by a farm's stocks of capital or land. This is consistent with the fact that fertilizer allocation decisions under the deposed Mengistu regime were politicized to the point where farmers had little control over use. Second, fertilizer is associated with a smaller factor share for cattle and a larger share for land, meaning that those who control land may gain relative to the individual farmers who own cattle as the country develops agriculturally. Third, farms without fertilizer in northwest and central Ethiopia tend to be too small, a problem due to population pressures on the land and communal methods of land allocation. This suggests that land allocation institutions should adjust by distributing land to a smaller but more economically viable number of farmers.     

Impact of Genetically Engineered Varieties on the Cost Structure of Corn and Soybean Production in Canada

This paper investigates the impact of genetically engineered (GE) varieties on the cost structure of corn and soybean production in Canada. Employing an adoption index for each farm and a time trend with farm‐level data on production costs of grain corn and soybeans from 2000 to 2007, a translog cost function and the associated input‐share equations are estimated. The use of the adoption index improves the estimates of technological change and multifactor productivity (MFP) growth. The results demonstrate that the adoption of GE corn and soybean reduced the variable costs of production by 0.62% per year. The MFP of corn and soybean grew by 2.0% per year during the study period, and 31% of this growth is attributable to GE varieties of these crops. The results also reveal that the adoption of GE varieties reduced the cost shares of fertilizer, herbicides and pesticides, and machinery in corn and soybean production. While the adoption of GE varieties increased the cost shares of seeds and custom works including labor, only the former was statistically significant.     

土地流转背景下缺水地区农用水权初始分配——基于投影寻踪混沌粒子群优化模型分析

[目的]文章从公平性和效率性2个方面选取6个指标构建了缺水地区微观主体农用水权初始分配指标体系,在该指标体系基础上,提出了投影寻踪混沌粒子群优化模型,研究了在土地流转背景下如何对缺水地区微观主体农用水权进行初始分配的问题。[方法]该文利用了投影寻踪技术对微观主体农用水权初始分配问题进行降维处理,采用混沌优化和粒子群优化算法寻找最优投影方向,并通过算例验证分析证明了该模型的可行性、合理性和有效性,为农用水权初始分配问题提供了相应的方法和思路。[结果]研究认为,土地流转使农业生产向土地规模化、经营主体职业化、分工专业化方向发展,为农用水权在微观主体之间进行初始分配提供了条件;农用初始水权明晰有利于缺水地区优化农业用水结构,节约农业用水,实施农用水权置换,促进农业用水转向第二、三产业,以推动缺水地区产业结构优化升级、社会经济转型发展;在农用水权初始分配过程中各指标重要性水平不能主观评估,应当由不同地区的样本数据驱动,客观地计算决策方案的最优值,公正地确定权重和水权分配比例。[结论]农用水权初始分配应考虑法律制度政策、社会经济、生态环境等多种因素,以构建完善的农用水权初始分配体系。     

How financial investment distorts food prices: evidence from U.S. grain markets

Convergence between commodity futures prices and the underlying physical assets at each contract's expiration date is a pivotal condition for the market's functioning. Between 2005 and 2010, convergence failed for several U.S. grain markets. This article presents a price pressure‐augmented commodity storage model that links the scale of nonconvergence to financial investment channeled through indices, which are traded in commodity futures markets. The model is empirically tested, using Markov regime‐switching regression analysis. Regression results strongly support the model's predicted link between index investment and the extent of nonconvergence for three grains traded at the Chicago Board of Trade: wheat, corn, and soybeans.     

Property portfolio allocation: A multi‐factor model

Summary

The objective of the paper is to describe a method of portfolio allocation currently being developed in the property sector. The model applies a multi‐index approach to portfolio decision making and enables investors to explore the effects of changing their allocational decisions. In estimating the parameters required for the model, we explain the method which can be used to adjust for smoothing effects on returns caused by the valuation process. Although the model is still at the development stage, the approach is general and can be applied both to allocating funds within a mixed‐asset portfolio or between different types of property within a wholly property‐orientated portfolio.     

基于空间信息重构技术的东北三省大豆时空演变研究（1980—2010年）

［目的］东北三省是我国大豆生产的重要基地,也是国家种植结构调整的重点区域。研究分析了1980—2010年东北三省大豆时空演变特征,为合理制定种植结构调整政策、加快推进农业供给侧结构性改革提供科学的空间信息参考。［方法］综合卫星遥感技术和空间信息重构模型优势,基于交叉信息熵方法,构建了作物空间信息重构模型SPAM China,对1980—2010年东北三省大豆种植空间分布、时空演变、重心迁移等进行了研究。［结果］1980—2010年东北三省大豆种植区域小幅增加,大豆种植面积栅格数量从6 703个增加至7 214个,松嫩平原、三江平原以及吉林省中部地区是东北三省的大豆主产区; 种植面积大幅增加,单位栅格面积增加1 000hm2以上的栅格数量增加明显,面积增加区域主要位于北纬47°~50°之间和东经1255°~131°之间; 东北三省大豆种植面积重心分别向东迁移10620km,向北迁移20857km,辽宁省、吉林省大豆种植面积重心南移,黑龙江省基本保持不变。［结论］1980—2010年东北三省大豆种植面积空间分布小幅增加,但时空变化特征显著,种植面积重心向北向东迁移。     

Abstracts of Award-Winning Theses

This thesis determines the tradeoff between producer welfare and the provision of environmental benefits, through reduced soil erosion and fertilizer applications, on agricultural working land. A land-use allocation model of two Iowa counties is formulated as a mathematical programming problem, building upon the Takayama and Judge framework. Slope is used to reflect terrain heterogeneity, such that the spatial allocation of land-use practices impacts economic and environmental outcomes via a yield damage function and differentiated rates of soil erosion. The model differs from prior empirical models in that it includes both crop and livestock production, which gives the model the flexibility to choose whether the two activities are optimally nonseparable.
Price policy analysis indicates that the land use allocation is relatively insensitive to changes in commodity prices, i.e., altering commodity-based support payments is insufficient to attain environmental improvements. Several "green" policy instruments are simulated to estimate the cost to producers of reducing environmental damages. Limiting soil erosion with either a regulatory standard or a per unit tax reduces the average return to land by 10%. Shifting current income support payments into a system of payments for conservation land management practices, similar in essence to the Conservation Security Program, cannot attain the same soil erosion reduction with less cost to producers. Overall, the inelastic response of land use practices to commodity prices indicates that targeting the use of productive inputs, as opposed to commodity outputs, may be a more efficient means of attaining environmental improvements.     

Cap reform: modelling supply response subject to the land set-aside

This paper uses duality theory to develop a model of European Community agriculture. The model is used to investigate the impact of the land set-aside provision of the recent package of reforms of the Common Agricultural Policy. We assume that producers chose output and variable input levels that maximize difference between revenue and variable cost. By including first-order conditions for the allocation of land across its uses, we impose that the observed allocations are profit-maximizing allocations. To overcome the problem of incorporating many outputs into an estimable production structure, we imposed a priori the restriction that the technology was weakly separable in major categories of outputs. With this restriction, it was possible to model production decisions in stages using consistent aggregates in the latter stages.     

耕地生产、生态功能视角下巨型城市区耕地补偿分区与补偿金配置研究

研究目的：探讨巨型城市区耕地生产、生态多功能需求下耕地补偿分区及补偿金配置模式。研究方法：文献资料法和模型分析法。研究结果：耕地补偿分区以耕地功能供需关系为直接依据,以区域公平为出发点;食物生产功能应是各级补偿分区的第一准则,生态服务功能应作为该功能需求强烈的巨型城市区的第二准则;复杂的层级式行政管理体制下,粮食安全视角的补偿金配置应以省级补偿关系为起点,兼顾土地利用效率理论及区域主体功能定位,采用自上而下的路径配置到末级实施单元;生态安全视角的耕地补偿面向巨型城市区内部,补偿分区及补偿金测算可直接到末级实施单元,不需要复杂的资金配置体系。研究结论：提出“粮食安全与生态安全二元制的巨型城市区耕地补偿分区模式及补偿金配置模型”,珠三角的案例分析验证了模式及模型的良好可行性。     

农村水库移民农地转入意愿及其影响因素——以贵州平桥水库安置区为例

水库农民搬迁失地后,如何解决移民安置的土地调配问题,预防搬迁致贫的风险,对移民生计恢复和生产安置具有重要意义。以贵州省平桥水库移民安置区实地调研数据为基础,构建移民基本特征、农地资源禀赋、农地流转条件及环境感知程度的指标体系,并构建logistic回归模型,分析移民市场化土地流转转入农地意愿的影响因素。结果表明:移民家庭结构对农地转入意愿有显著影响,融资机会能明显提高移民农地转入意愿,征地前土地资源数量和转入的农地价值对移民农地转入意愿有显著正向作用,政府补贴、社会养老保险和农地流转组织并未产生显著影响。建议应因户施策,合理引导,增加融资机会和补贴,健全农村社会保障体制,降低土地依赖性,完善移民安置区土地流转市场,积极引导移民参与农地流转。     

基于用地企业视角的土地资源配置效率研究

研究目的:通过随机抽样调查,获取W城市3个开发区7个行业243家企业数据,基于C-D生产函数理论构建用地企业视角的土地资源配置效率测度模型,测算不同类型用地企业的土地资源配置效率。研究方法:数据包络分析方法。研究结果:大多数企业的土地资源配置效率都是DEA无效的,土地资源投入冗余值较大,配置效率低下;不同类型企业或同类型的不同企业之间土地资源配置效率的差异性显著。研究结论:当前企业在生产过程中的土地资源配置效率存在巨大提升空间,提升企业的土地资源配置效率是促进土地资源节约集约利用的重要措施之一。     

Joint Estimation of Technology Adoption and Land Allocation with Implications for the Design of Conservation Policy

One challenge to estimating the parameters of a technology adoption model is that technology is selected jointly with land allocation. The article estimates a nested logit model of technology and crop choices that accounts for unobserved correlation among decisions. Estimation is conducted with a data set of adoptions, in contrast to the more common approach of using cross-section observations of existing technologies. Estimation results support the choice of a nesting structure as opposed to a more standard multinomial logit model. Adoption of precision irrigation technology is shown to be more sensitive to financial incentives affecting input price and technology cost than suggested by previous studies.     

价格扭曲与边际产出孰轻孰重？ ——建设用地资源错配的来源分解

研究目的:探究中国城市建设用地资源错配的产生机理并对其来源进行分解,为纠正城市建设用地资源错配提供参考。研究方法:基于Cobb-Douglas生产函数,采用定量分析与定性分析相结合的方法,并尝试对HSIEHKLENOW的资源错配模型进行拓展。研究结果:考察期内工业、住宅用地存在过量配置,而商服用地则配置不足,且造成三类建设用地资源错配的主要来源不尽相同。研究结论:短期内纠正存量建设用地在不同行业间的资源错配已成为土地资源约束下提高经济产出的最佳选择。     

EU and US Regulations for Handling and Transporting Genetically Modified Grains: Are Both Positions Correct?

Differences in the way GM grains are treated in the US and the EU motivate the question of whether there is a single correct policy towards identification of such products. This issue is addressed here, based on a mathematical model that assumes that the cost of maintaining identity on non-GM markets is borne by the non-GM industry. The economic welfare impacts of introducing GM technology depend on the levels of consumer concern and production cost savings, and the cost of maintaining non-GM grain identity. The introduction of a new cost-reducing GM technology often increases total welfare as one might expect. However, society loses when GM production cost-savings are small and consumers are highly concerned about GM grain because introducing GM technology creates a need to preserve the identity of non-GM grain. Taken together, the results suggest that the US may have maximized welfare by not requiring labeling of GM corn and soybeans, and that the recently approved EU legislation enforcing labeling of GM crops also makes sense in the EU. The reason for this is that consumer concern in the EU appears to be greater than in the US, and fewer EU producers stand to benefit from cost savings in GM corn and soybean production.     

农户视角下湖北省耕地集约利用影响因素分析

研究目的：基于农户视角分析耕地资源集约利用的影响因素及其作用机理,探讨促进耕地集约利用的途径与措施,为提高中国耕地资源配置和利用效率提供新的研究视角。研究方法：双对数函数模型分析法。研究结果：农民户均劳动力人数、农民人均纯收入和农业比较收入对耕地集约利用具有明显的正向驱动作用;农业生产资料价格指数对耕地集约利用具有较明显的负向影响;而耕地的产权保障和农业补贴政策对耕地集约利用的影响不显著。研究结论：耕地利用集约度实质上是农户不同耕种行为的表现结果,提高耕地利用集约度的关键是采取相应的政策措施激励农户的耕种行为;增加农户农业收入、控制农业生产资料价格,稳定或适度降低农业生产成本等是促进农户集约利用耕地资源的重要经济手段;深化农地产权制度改革和调整完善农业补贴政策是提高耕地利用集约度的重要制度基础。     

Market interdependence and volatility transmission among major crops

This article provides a comprehensive analysis of the dynamics of volatility across major agricultural commodities in the United States. Volatility interactions across markets may lower the effectiveness of diversification strategies to mitigate price risks and should be taken into account when analyzing the pricing behavior of different agricultural commodities. We follow a multivariate GARCH approach to evaluate the time evolution of conditional correlations and volatility transmission across corn, wheat, and soybeans price returns on a daily, weekly, and monthly basis. The period of analysis is from 1998 to 2012. The estimation results indicate a lack of lead‐lag relationships between corn, wheat, and soybeans price returns at the mean level. We find, however, important volatility spillovers across commodities, particularly at the weekly and monthly level. Wheat and corn seem to play a major role in terms of volatility transmission. Despite the supposed higher financial market integration of agricultural commodities, we do not observe that agricultural markets have become more interdependent in recent years.     

中国城市土地供给错配：特征事实及对 全要素生产率的影响效应

研究目的：探究城市土地供给错配的典型特征,明晰城市土地供给错配对全要素生产率的影响,为提升土地配置效率和全要素生产率提供经验证据。研究方法：从土地供给过度与供给不足视角解析城市土地错配对全要素生产率的影响机制,通过空间一般均衡模型构建城市土地供给错配指数,利用面板计量模型和中介效应模型进行实证分析及中介效应检验。研究结果：（1）中国城市土地供给错配表现出明显的差异性：不同地区、城市规模、人口流动方向分别呈现出“东少西多”“阶梯递减”“逆向配置”特征。（2）城市土地供给错配对全要素生产率产生负向影响,影响效应在不同类型城市存在异质性,城市土地供给过度对全要素生产率的负向作用强于土地供给不足。（3）城市土地供给过度通过创新创业发展和产业结构优化双重路径显著抑制了城市全要素生产率,土地供给不足主要通过产业结构优化对城市效率产生显著的负向影响。研究结论：应警惕土地配置过度的“经济效率”陷阱,强化建设用地指标分配的人地挂钩机制,因城施策提升土地资源配置效率。     

Risk aversion and land allocation between annual and perennial crops in semisubsistence farming: a stochastic optimization approach

This article analyzes the effect of production uncertainty on farmland allocation decisions between perennial and annual crops, focusing on a representative farmer's attitude toward risk. A dynamic stochastic optimization model that considers net planting—the difference between new plantings and removals of perennial crops that achieve full production cycle—is used. The effect of uncertainty on the representative farmer's decisions to increase or decrease perennial crops’ acreage, on the optimal path, is examined. Our results reveal that the response of optimal path of net planting to uncertainty related to perennial crop production is highly affected by the farmer's attitude toward risk. A risk‐averse or a low‐risk loving farmer tends to reduce land allocation to perennial crops under uncertainty, while a high‐risk loving farmer will do exactly the opposite. Also, due to disutility of farming, the farmer tends to reduce land allocation to perennial crops when prices are high enough for him to attain a desired income level expectation. One implication of this research is the need for mechanization—in sub‐Saharan countries in particular—that increases per‐acreage yield and output in semisubsistence agriculture.