地下水可交易水权制度框架及其作用研究

为解决地下水超采与浪费问题,研究在地下水管理中引入可交易水权制度,认为通过地下水水权交易,可以满足新进入者用水需求,有效地控制整个区域的地下水可开采总量。通过用水户之间的水权交易,可促进地下水资源在各用水主体间优化配置。为保障这一制度的运行,建议建立地下水可交易水权制度组织保障体系及法律保障体系。     

Integrating crop modelling and production economics to investigate multiple nutrient deficiencies and yield gaps

A method is described for integrating crop modelling and production economics to quantify optimum applications of multiple nutrients and yield gaps. The method is demonstrated for crop production in the high‐rainfall zone of southern Australia. Data from a biophysical crop model were used to overcome the persistent problem of inadequate experimental data. The Mitscherlich function was expanded to accommodate four variable inputs – nitrogen, phosphorus, potassium and sulphur – and the expansion path was used to determine the economic optimum application of all four nutrients. Modelling revealed the state‐contingent yield potential and the extent to which unrealised yield could be explained by profit‐maximising behaviour and risk‐aversion by growers. If growers and their advisors were guided by the methods described, they would be better equipped to assess crop nutrient demands and limitations, predict yield potential, additional profit and the risks associated with high input systems in a variable climate. If scientists were more aware of the extra profits and the risks involved (as well as the quantitative relationships between inputs and outputs) when thinking about what to produce and how to do so, they would be more circumspect about the net benefits to be obtained from closing yield gaps.     

工程定额在工程造价管理中的地位与作用

针对不同的工程造价管理模式,从工程建设成本和工程交易价格两个方面分别阐述了工程定额在工程造价管理不同阶段中的地位和作用,认为,企业定额是工程量清单计价模式下工程造价管理体制变革的必然结果。     

Ambiguity of measured WTP for quality improvements when quantity is unconstrained: a note

This paper addresses the issue of how to estimate by contingentvaluation methods the maximum price consumers are willing topay when a new quality is available for a market good for whichquantity adjustments are possible. We argue that current practice,which typically does not specify a quantity when asking consumersthe price they are willing to pay for a new quality product,fails to identify prospective consumers' behaviour when theyare free to adjust the quantity purchased. Theoretical modelsare discussed for assessing the maximum price consumers arewilling to pay in these cases, and econometric approaches toaddress these situations are discussed.     

Capacity reduction,quota trading and productivity: the case of a fishery*

We present the first ex post study that quantitatively analyses the effects of a licence buy‐back and enhanced quota trading on the profitability and productivity of individual vessels in a fishery. Using firm‐level data and a profit index decomposition method, we find that small and large vessels and three different trawler fleets all experienced substantial productivity gains in the year immediately following a licence buy‐back and the establishment of a quota brokerage service. The apparent ongoing benefits of the buy‐back and increased quota trading over the sample period are in stark contrast to the generally unfavourable long‐term outcomes commonly associated with vessel buy‐backs in input‐controlled fisheries.     

Land Invasions,Insecure Property Rights and Production Decisions

This paper investigates empirically the effect of land invasions on farm production decisions. The main hypothesis is that more invasions in a region are associated with lower investment, and in particular a bias towards annual crops as opposed to long‐term crops. We use a county‐level dataset for the state of Paraná, Brazil, from 2003 to 2007, with 1,995 observations. The panel data structure allows us to control for fixed effects, such as the formalisation of land titles and land concentration, which might be correlated with the intensity of invasions. An instrumental variable fixed effects model was estimated to avoid other sources of bias. Our main finding is that land invasions are associated with lower long‐term crop production and a higher percentage of annual crops, which could accelerate land degradation, and undermine environmental sustainability.     

Market Advisory Service Recommendations and Wheat Producers' Selling Decisions

This study uses actual producer transaction data to determine how Oklahoma wheat producers' selling decisions compare to recommendations from market advisory services and market incentives as reflected in futures spreads. Results show that producers responded to expected returns to storage as measured by futures spreads. Also, Oklahoma producers make marketing decisions that are either unrelated or the opposite of recommendations from market advisory services .
La présente étude a utilisé des données de transactions réelles pour comparer les décisions de vente des producteurs de blé de l'Oklahoma avec les recommandations faites par des services consultatifs et les stimulants du marché tels que reflétés dans les écarts. Les résultats ont montré que les producteurs ont réagi aux rendements attendus de l'entreposage tels que mesurés par les écarts. De plus, les décisions commerciales des producteurs de l'Oklahoma sont soit indépendantes des recommandations des services conseils, soit totalement contraires à ces recommandations .     

Gains from quota trade: theoretical models and an application to the Danish fishery

We provide a framework for evaluating potential effects of introducingtradable quotas to a sector. The effects depend on the economiesof scale and scope of the production technology, and on firms'ability and willingness to learn best practice methods (catchingup) and to change their input and output composition (mix).To illustrate our approach, data from the Danish fishery areused to calculate the potential gains from introducing individuallytransferable fishing quotas. Data envelopment analysis is usedto model the production technology. We find that pure reallocationis as important as pure learning, i.e. quota reallocation withoutcatching-up is as valuable as learning best practice with fixedallocations.     

Measuring productivity growth when technological change is biased–a new index and an application to UK agriculture

Productivity growth is conventionally measured by indices representing discreet approximations of the Divisia TEP index under the assumption that technological change is Hicks-neutral. When this assumption is violated, these indices are no longer meaningful because they conflate the effects of factor accumulation and technological change. We propose a way of adjusting the conventional TFP index that solves this problem. The method adopts a latent variable approach to the measurement of technical change biases that provides a simple means of correcting product and factor shares in the standard Tornqvist-Theil TFP index. An application to UK agriculture over the period 1953–2000 demonstrates that technical progress is strongly biased. The implications of that bias for productivity measurement are shown to be very large, with the conventional TFP index severely underestimating productivity growth. The result is explained primarily by the fact that technological change has favoured the rapidly accumulating factors against labour, the factor leaving the sector.     

Agricultural Policy Reform and Off‐farm Labour Decisions

Off‐farm labour decisions of a sample of Kansas farmers are evaluated. The central question of our analysis pertains to whether 1996 US farm policy reforms may have altered the decisions to work off the farm. The effects of policy decoupling on off‐farm labour are complex: different aspects of policy changes can have opposing effects on off‐farm work decisions. Essentially, this makes this issue an empirical question. Results show that the introduction of fixed, decoupled payments in 1996 might have reduced the likelihood of off‐farm labour participation. However, the new policy environment may have increased farm households’ revealed aversion to risk, motivating a higher participation in non‐farm labour markets. The effects of 1996 policy reforms on farm income variability could have been attenuated by changes in US crop insurance programmes and by an increase in emergency assistance payments towards the end of the 1990s. The reduction in price supports may have increased the motivation for working off the farm. The net effect of the overall reforms on off‐farm work participation is not likely to have been large.     

Information Asymmetries and Consumption Decisions in Organic Food Product Markets

Organic agriculture is a rapidly growing segment of most developed agricultural economies around the world. To stimulate growth and circumvent supply‐side market failures that emerge when organic products are not segregated, governments have introduced regulations concerning the certification and labeling of organic food. While certification and labeling satisfy market demand for information provision, the introduction of these activities creates incentives for the mislabeling of conventional food as organic. Despite the incentives for, and the incidence of, mislabeling in organic food product markets, this issue has not been analyzed systematically. In fact, the possibility of mislabeling has been customarily neglected by economic studies of markets for credence goods in general. This paper addresses the issue of product type misrepresentation in organic food product markets and develops a model of heterogeneous consumers that examines the effect of mislabeling on consumer purchasing decisions and welfare. Analytical results show that, contrary to what is traditionally believed, while certification and labeling are necessary, they are not sufficient for alleviating failures in organic food product markets. The effectiveness of labeling depends on the level of product type misrepresentation. Consumer deception through mislabeling affects consumer trust in the labeling process and can have detrimental consequences for the market acceptance of organic products. When extensive mislabeling occurs, the value of labeling is undermined and the organic food market fails. L'agriculture biologique est un secteur qui prend rapidement de l'expansion dans la plupart des pays agricoles industrialisés. Pour stimuler la croissance de ce secteur et éviter les problèmes d'offre qui surviennent quand il n'y a pas ségrégation des denrées, les gouvernements ont adopté des règlements sur la certification et l'étiquetage des produits biologiques. Même s'ils satisfont la demande d'informations sur le marché, la certification et l'étiquetage ouvrent la porte à l'usage abusif du terme “biologique” sur l'étiquette des denrées ordinaires. Or, bien que les producteurs soient tentés d'utiliser le terme à tort et à travers et en dépit des incidences d'un tel comportement, le phénomène n'a jamais été analysé de manière méthodique. De fait, les analyses économiques sur le marché des denrées alimentaires, en général, négligent souvent la possibilité de fausses déclarations sur l'étiquette des produits. L'article que voici aborde ce problème sur le marché des aliments biologiques et propose un modèle qui tient compte des effets d'un étiquetage fallacieux sur les achats et le bien‐être de consommateurs hétérogènes. Les résultats de l'analyse indiquent que, contrairement à ce qu'on croit, la certification et l'étiquetage, bien que nécessaires, ne suffisent pas à atténuer les problèmes observés sur le marché des aliments biologiques. En effet, l'efficacité de l'étiquetage dépend du nombre de fausses déclarations. La déception qui résulte d'une fausse déclaration ébranle la confiance des consommateurs dans le système d'étiquetage, si bien que les produits biologiques sont mal accueillis sur le marché. Quand les fausses déclarations se multiplient, l'étiquette perd sa valeur et il devient impossible de commercialiser les denrées biologiques.     

Family Composition and Off-Farm Participation Decisions in Israeli Farm Households

This article studies the relationship between the off-farm participation behavior of farm operators and their spouses and the demographic composition of the household. We focus on farm families without parents, siblings or partners, and examine the effects of the existence of elderly children of the farm couple. We find that both the father and the mother tend to reduce their participation in off-farm work as the number of elderly children rises. This result holds even after controlling for observed characteristics. We also find that the effect of elderly children stems from considerations related to both farm production and household production.     

Modelling a mixed system of air pollution fee and tradable permits for controlling nitrogen oxide: a case study of Taiwan*

A mixed-integer non-linear programming model that minimises the total regulatory costs of controlling nitrogen oxide is used to investigate how a newly proposed permit trading scheme in Taiwan, which incorporates the features of banking and a non-one-to-one trading ratio, may affect firms’ emission reduction strategies and permit trading decisions. Compared to the previous regulation where only an air pollution fee is used, the new regulation that requires a reduction in emissions by 10 per cent from the emission level in the year 2000 for a 5 year period will increase the costs by 77 per cent, which is equivalent to US$9.87 million. The design of banking and the increasing returns to scale characteristic of pollution control among firms might lead to an uneven reduction in emissions in each year. Setting a lower reservation rate for banking would, however, help maintain a more stable environmental quality without a significant loss to the government in terms of air pollution fee revenue.     

独联体国家粮食增产有望缓解全球供求紧张

面对国际粮食价格持续上涨,很多人担心地球能否生产足够粮食以满足人类各种需求.独联体则可能承担起这一重大的历史责任.