The Economics of Soil Erosion: Theory, Methodology and Examples

The purpose of the following paper is to provide an overview of an economic analysis of soil erosion, concentrating particularly on explaining the farm-level economics of soil erosion and discussing with examples the appropriate methodology for measuring on and off-site costs.Soil erosion

Modeling the deformation textures and microstructural evolutions of a Fe–Mn–C TWIP steel during tensile and shear testing

The high manganese austenitic steels with low stacking fault energy (SFE) present outstanding mechanical properties due to the occurrence of two strain mechanisms: dislocation glide and twinning. Both mechanisms are anisotropic. In this paper, we analyzed the effect of monotonous loading path on the texture, the deformation twinning and the stress–strain response of polycrystalline high Mn TWIP steel. Experimental data were compared to predicted results obtained by two polycrystalline models. These two models are based on the same single crystal constitutive equations but differ from the homogenization scheme. The good agreement between experiments and calculations suggest that the texture plays a key role in twinning activity and kinetics with regard to the intergranular stress heterogeneities. Rolling direction simple shear induces single twinning while rolling and transverse direction uniaxial tensions induce multi-twinning leading to lower twin volume fractions due to twin–twin interactions

Trade and Development in a Labor Surplus Economy

This paper looks at a model in which two countries trade agricultural and manufactured commodities. The manufactured-goods sector produces with increasing returns to scale under conditions of monopolistic competition. It is shown that an increase in land endowment (or an increase in agricultural productivity) can have negative welfare implications for both countries. This outcome can result under three different scenarios: asymmetries across countries, i.e. a North-South model, a neoclassical labor market in the home country's instead of a Lewisian market, and alternative utility functions.international trade, labor surplus economy, land expansion, monopolistic competition, North-South model

Managing the Black Sea Anchovy Fishery with Nutrient Enrichment and a Biological Invader

Many marine systems are subject to high nutrient loadings together with invasions by exotic species. Devising appropriate management responses is an increasing concern and one that has received relatively little attention from researchers. This paper considers the Black Sea anchovy fishery, which has benefited from the relaxation of a nutrient constraint, but has suffered from competition and predation by an invading comb-jelly (Mnemiopsis leidyi). We examine alternative hypotheses about the mechanism triggering outbreaks of the invader (sea temperatures versus nutrients), and the severity of these outbreaks, to see whether a constant escapement policy might be optimal for this fishery. If nutrient levels serve as the triggering mechanism, we argue a mixed blessing effect may be present, so that the effects of nutrient abatement for the anchovy fishery are uncertain. We specify our model empirically and show that a constant escapement policy would be viable under a scenario of reduced impacts from outbreaks of the invader and that nutrient abatement could be beneficial if nutrients trigger outbreaks.Mnemiopsis leidyi, nutrient abatement, stochastic bioeconomic model, biological invasion, Resource /Energy Economics and Policy, O3, O41, Q2, Q20, Q22,

Biodiversity and Geography

The paper combines an economic-geography model of agglomeration and periphery with a model of species diversity and looks at optimal policies of biodiversity conservation. The subject of the paper is "natural" biodiversity, which is inevitably impaired by anthropogenic impact. Thus, the economic and the ecological system compete for space and the question arises as to how this conflict should be resolved. The decisive parameters of the model are related to biological diversity (endemism vs. redundancy of species) and the patterns of economic geography (centrifugal and centripetal forces). As regards the choice of environmental-policy instruments, it is shown that Pigouvian taxes do not always establish the optimal allocation.biodiversity, new economic geography, agglomeration, species redundancy vs. endemism, environmental regulation

Trade and Development in a Labor Surplus Economy

This paper looks at a model in which two countries trade agricultural and manufactured commodities. The manufactured-goods sector produces with increasing returns to scale under conditions of monopolistic competition. It is shown that an increase in land endowment (or an increase in agricultural productivity) can have negative welfare implications for both countries. This outcome can result under three different scenarios: asymmetries across countries, i.e. a North-South model, a neoclassical labor market in the home country's instead of a Lewisian market, and alternative utility functions.international trade, labor surplus economy, land expansion, monopolistic competition, North-South model.

Biodiversity and Geography

The paper combines an economic-geography model of agglomeration and periphery with a model of species diversity and looks at optimal policies of biodiversity conservation. The subject of the paper is "natural" biodiversity, which is inevitably impaired by anthropogenic impact. Thus, the economic and the ecological system compete for space and the question arises as to how this conflict should be resolved. The decisive parameters of the model are related to biological diversity (endemism vs. redundancy of species) and the patterns of economic geography (centrifugal and centripetal forces). As regards the choice of environmental-policy instruments, it is shown that Pigouvian taxes do not always establish the optimal allocation.biodiversity, new economic geography, agglomeration, species redundancy vs. endemism, environmental regulation

Agricultural pricing and environmental degradation

The link between agricultural pricing and land degradation is often difficult to analyze empirically. The authors'understanding of how agricultural supply responds to changing prices in developing countries is incomplete. Even more incomplete is the author's analysis of subsequent impacts on the resource base sustaining agricultural production. Yet available evidence suggests that some important effects do exist, and much further analysis of them is warranted. The social, economic, and environmental relationships that determine the often countervailing effects of price changes on land use and management are extremely complex. Not enough is known about: (1) farming systems in developing countries; (2) open-access use and common property resource rights; (3) land tenure regimes and security; (4) access to technology and other farming systems information; (5) the distribution of wealth and income; and (6) coping strategies for variable climatic, economic, and social conditions. All these factors influence how rural households respond to price changes in terms of managing land and natural resources, and often they may override the incentive effects of price changes. Changes in pricing policies will then be less effective in correcting resource degradation than other approaches to dealing with its underlying causes. Such approaches include providing better research and extension advice, improving property rights and management, and establishing more secure tenure or access rights. At the same time, it is wrong to assume that poor farmers - even those in resource-poor regions far from major markets - are totally isolated from agricultural markets. Virtually all subsistence households require some regular market income for cash purchases of agricultural inputs and basic necessities; many small farmers provide important cash and export crops. So changes in market prices often significantly affect the livelihoods of rural groups. Clearly, the economic incentives emerging from these impacts will affect farmers'decisions to invest in land management and improvements. Just because we do not always understand the economic and social factors determining these incentive effects does not mean they do not exist. Nor should the complexity of the links between price changes and resource management - which sometimes appear counterintuitive - deter further analysis of the role of agricultural pricing in land degradation.Environmental Economics&Policies,Crops&Crop Management Systems,Agricultural Knowledge&Information Systems,Economic Theory&Research,Agricultural Research