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991.
Michael J. Livingston 《Revue canadienne d'agroeconomie》2007,55(4):515-526
Cold treatment periods, and associated levels of quarantine security, that maximize net US welfare under USDA's current medfly detection and control program are examined using a deterministic bioeconomic optimization model . As anticipated, the efficient level of quarantine security is shown to increase with indices of medfly pressure (initial infestation rates) in areas in which the medfly is known to exist (the QCs) . Efficient cold treatment periods and weighted mean medfly survival rates are 8, 11, and 12 days and 5.0 × 10–2, 1.7 × 10–3, and 5.2 × 10–4 under low, moderate, and high initial infestation rates, respectively. When model output is averaged across initial infestation rates, an 11‐day cold treatment period, resulting in a weighted mean medfly survival rate of 1.6 × 10–3, maximizes US welfare. These findings suggest that the current minimum cold treatment period of 14 days and the current objective of US cold treatment policy—the probit 9 level of quarantine security—are economically inefficient. Adopting the 11‐day cold treatment period is shown to increase US social surplus by an annual $24.9 million, of which $21.5 and $3.4 million would accrue to US consumers and producers, respectively, and QC producer surplus by an annual $24.8 million. Nous avons examiné, à l’aide d’un modèle déterministe d’optimisation bioéconomique, les périodes de traitement par le froid et les niveaux de quarantaine de sécurité connexes qui maximisent le bien‐être net des États‐Unis d’après le programme actuel de détection et de lutte contre la cératite, instauré par le USDA. Comme prévu, le degré de quarantaine de sécurité efficace augmente en fonction des indices de pression des ravageurs (indices d’infestation initiale) dans les pays où la cératite est présente (pays dont les produits sont soumis à une quarantaine). Selon qu’il s’agit d’un indice d’infestation initiale faible, moyen et élevé, les périodes de traitement par le froid efficaces sont de 8, 11 et 12 jours respectivement et les taux de survie moyens pondérés de la cératite de 5,0 × 10–2, 1,7 × 10–3, et 5,2 × 10–4 respectivement. Lorsque l’on établit la moyenne pondérée de la sortie du modèle par taux de survie, une période de traitement de 11 jours et un taux de survie moyen pondéré de 1,6 × 10–3 maximisent le bien‐être des États‐Unis. Ces résultats donnent à penser que la période minimale actuelle de traitement par le froid de 14 jours et la politique actuelle concernant le traitement par le froid (la norme probit 9) sont économiquement inefficaces. L’adoption d’une période de traitement par le froid de 11 jours augmenterait le surplus collectif des États‐Unis de 24,9 millions (M$) par année, dont 21,5 M$ et 3,4 M$ reviendraient aux consommateurs et aux producteurs des États‐Unis respectivement, et un surplus de 24,8 M$ par année aux producteurs des pays dont les produits sont soumis à une quarantaine. 相似文献
992.
993.
Michael Harris & Iain Fraser 《The Australian journal of agricultural and resource economics》2002,46(2):139-192
In this paper an extensive review of the theoretical and applied literature on natural resource accounting (NRA) is provided. The review begins by explaining the economic theory that underpins NRA, contrasting welfare and sustainability as policy goals, and presenting various distinct conceptions of national income. The state of play regarding official revisions to the system of national accounts (SNA) with respect to natural resources and the environment is presented and controversial areas are highlighted. Finally, the economic literature on proposed revisions, and applied studies that have proceeded using these methods, is summarised and critiqued. We argue that much of the literature proceeds with weak conceptual foundations, and that typical case studies produce results that are ambiguous in interpretation. Moreover, we highlight fundamental tensions between economic theory and national accounting methodology, and conclude that one outcome of this has been the insufficient attention paid by economists to the revisions to the SNA; instead devoting time and effort to 'freelance' NRA case studies utilising sometimes ad hoc methods from the economic literature. 相似文献
994.
Risk, uncertainty, and learning in adoption of a crop innovation 总被引:1,自引:0,他引:1
Risk and uncertainty have often been suggested as causes of poor adoption of rural innovations, but empirical evidence has been scarce. This study focuses on a new crop‐type, chickpeas, in Western Australia to gather such evidence. The empirical models developed are based on a theoretical framework that conceptualizes adoption as a dynamic decision process involving information acquisition and learning‐by‐doing by growers who vary in their managerial abilities, risk preferences, and their perceptions of the profitability and riskiness of the innovation. Learning encompasses improvements in skill as well as reductions in uncertainty. An annual face‐to‐face survey of over 100 farmers was conducted over 3 years, eliciting the farmers' risk attitudes and their subjective distributions of yields and prices. Two limited dependent variable models, Tobit and Probit, are used to estimate the empirical model. There is a high degree of goodness‐of‐fit for both models. The study provides strong empirical support for the primarily economic character of the adoption decision, and highlight the importance of economic risk in the process. The two risk‐related factors with greatest impact on the adoption decision were risk aversion and relative riskiness of the innovation. Risk aversion tended to reduce adoption, and to do so to a greater extent as relative riskiness and scale increased. Results also reveal the key role that trialing of the innovation plays in adoption. 相似文献
995.
996.
Technology choice under changing peanut policies 总被引:2,自引:0,他引:2
The effect of marketing quotas and price supports on technology adoption are examined for peanut production in the southeastern United States using a real options model of investment with output price and yield uncertainty. The optimal choice of peanut production technology (dryland versus irrigated) in the southeast is shown to depend on price supports and how they change. The manner in which price supports change will have an effect on the choice and rates of abandonment or adoption of production technologies. 相似文献
997.
James M. MacDonald Michael E. Ollinger 《American journal of agricultural economics》2005,87(4):1020-1033
Beefpacking underwent a dramatic transformation in the 1970s and 1980s, as plants got much larger and industry concentration rose dramatically. We use individual Census Bureau plant records to analyze the sources of the transformation. We find that there were modest but extensive scale economies in packing plants, covering the full range of plant sizes, and that such economies became more important throughout the period of the study. As production shifted to larger plants, we estimate that the industry's aggregate processing costs fell by 35.3% by 2002, compared to what they would have been without consolidation. 相似文献
998.
Fabio R. Chaddad Michael L. Cook Thomas Heckelei 《Journal of Agricultural Economics》2005,56(3):385-397
This study examines the presence of financial constraints in US agricultural cooperatives. We test the cooperative capital constraint hypothesis with a panel data econometric analysis of agricultural cooperatives’ investment behaviour. Regression results suggest that agricultural cooperatives’ capital expenditures are significantly affected by the availability of internal funds. Results also indicate that the sensitivity of investment to cash flow is correlated with cooperative structural characteristics. 相似文献
999.
John D. Mullen Julian M. Alston Michael K. Wohlgenant 《The Australian journal of agricultural and resource economics》1989,33(1):32-47
An equilibrium displacement model of the world wool top industry is used to estimate the returns to the Australian wool industry from productivity improvements in farm production, in top making and in textile manufacturing. The returns to the industry from these different types of research and development are sensitive to the extent of substitution possibilities between Australian wool and other inputs used by the wool processing and textile industries but it appears that research resources have to be much more efficient in off-farm activities for the Australian wool industry to receive benefits similar to those from farm research activities. 相似文献
1000.
Many skeptics of trade liberalization in the developing world argue that lowering trade taxes can cause significant fiscal
pressures in countries particularly reliant on these taxes and result in a reallocation of resources away from important development
goals. This paper evaluates whether there is evidence that central governments systematically change the composition of spending
priorities in the wake of lowered trade tax revenues as a share of total government revenues. We find no systematic evidence
for this concern in a sample of 51 developing countries for the 1991 through 2005 period. 相似文献