Technology choice under changing peanut policies

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.     

Evaluating the impact of rising fertilizer prices on crop yields

Because of tensions on fossil energy and phosphorus markets, the rise in fertilizer prices observed during the last decades may continue in the future, putting into question production pathways relying heavily on crop intensification. To evaluate how, in this context, economic choices may alter crop yields, we first construct different fertilizer price scenarios to 2050 based on an econometric relation with oil and gas prices. Other possible scenarios, such as the continuation of historical trends, are also considered. The resulting changes in fertilizer price range between +0.8% and +3.6% per year over the 2005–2050 period. These scenarios are tested in a global land‐use model incorporating an endogenous representation of the land–fertilizer substitution. We find that the supply‐side response to rising fertilizer prices could lower crop yields in 2050 from ?6% to ?13%, with a corresponding increase in global cropland area ranging between 100 and 240 Mha if the demand for food and nonfood products has to be met. The sensitivity of these results is tested with regard to assumptions on food consumption, change in potential yield and nutrient use efficiency.     

Protected areas in fisheries: a two‐patch,two‐species model*

The use of marine protected areas as a fishery management tool has been suggested as a hedge against management failures and variation in harvests. A stochastic bioeconomic model of a hypothetical predator–prey fishery is used to test the performance of protected areas in a fishery with heterogenous environments. Protected areas are analysed under density‐dependent and sink‐source dispersal relationships between the subpopulations that occur within the fishery. Differing management structures governing resource extraction are analysed. The focus of the study is placed on the biological and management characteristics that yield benefits to both fishers and society. It is shown that the establishment of a protected area improves fishery rent and lowers harvest variation. This result is sensitive to both current management controls and the correlation between species and patches.     

Dynamics and Long-run Structure in U.S. Meat Demand

Empirical analysis, based on a general dynamic Almost Ideal Demand System, shows the commonly used autoregressive and partial adjustment processes are restrictive to meat demand data. This study derives a linear specification in levels form to investigate dynamics in a general framework. Merging a long-run steady state structure with short-run dynamics results in consistent and robust long-run demand elasticities Une analyse empirique, basée sur un systéme dynamique général de demande quasi optimale, montre que les mécanismes courants d'ajustement autorégressif et d'ajustement partiel ont un effect restrictif sur l'évaluation des données de la demande de viande. Les auteurs proposent une spécifcation linéaire par niveaux pour examiner la dynamique du cadre général. La combinaison d'une structure stable de longue durée avec une dynamique de courte période a produit des élasticités cohérentes et solides de la demande à long terme     

ON DECISION-MAKING FOR MAXIMUM PROFIT PER UNIT OF TIME FROM BATCH PRODUCTION

Finding ration sequences which result in maximum profit per day from fattening batches of livestock over successive weight intervals has posed difficulties in earlier studies. Fractional and dynamic programming are considered as solution methods and illustrated for a problem previously solved by total enumeration. Other problems are discussed which would be best solved by a combination of the two methods. A novel proposal is made for using the two methods to maximise the present value of returns from sequencing weight gains over infinite production cycles.     

AGRICULTURAL FLOOD ALLEVIATION BENEFIT ASSESSMENT: A CASE STUDY

The cost of flooding on farm land depends on land use, on the frequency, seasonality, duration and depth of flooding, and on water quality. This paper describes a method to calculate the average annual cost of flooding and the extra benefits or costs associated with given changes in flooding regime, illustrated by means of a simplified case study which examines the agricultural benefits of reduced summer flooding on grass in an area of environmental importance. Using hydrological and agro-economic data, the method derives the cost of individual flood events occurring in any one month for a given land use, weights these according to observed seasonality of flood flows, and derives average annual costs per hectare and for the floodplain as a whole for given levels of flood risk. The method is useful for appraising river flood alleviation schemes whereby the effects of changes in flood risk, flood seasonality or land use can be assessed.