Farm-to-market transaction costs and specialisation in small-scale agriculture: Explorations with a non-separable household model

Using an integrated household model with endogenous transaction costs, this article illustrates how, even in the absence of risk, the tension between gains from specialisation and corresponding increases in transaction costs may lead to enterprise diversification on small farms. A numerical example illustrates that this tension may contribute to the prevalence of inter-cropped cash-crops on small farms, in apparent disregard for foregone yield and income from greater specialisation involving pure-stands. By implication, measures that augment households' abilities to override trading costs may be critical complements to efforts seeking to raise productivity and incomes in small-scale agriculture via increased specialisation.

Modelling and monitoring land-cover change processes in tropical regions

Transformations in terrestrial ecosystems are increasingly regarded as an important element of global change. Quantitative data on where, when and why land-cover changes take place globally are still incomplete. This article reviews recent approaches to the monitoring and modelling of deforestation and dryland degradation in tropical regions. The review highlights the requirement to tailor the investigation method to the specific research question of interest. Different techniques to monitor land-cover changes at regional scales are analysed. The following modelling scenarios are discussed and illustrated by specific studies: projection of future land-cover changes with descriptive models, explanation of land-cover changes with empirical models, projection of future spatial patterns of changes with spatial statistical models, test of scenarios on future changes in land-cover with dynamic ecosystem models, and design of policy interventions with economic models. The article stresses the needs for a better integration of social science knowledge in land-cover change models and for a comprehensive theory of land-use changes