The history of economic models of land degradation is short, and yet fundamental changes have occurred in the structural assumptions underlying land degradation models and the questions they are used to address. Many of these changes are the results of studies in developing countries, where the problem of land degradation is proportionally much more severe. In this paper I first review the conventional single-farm approach, then present and explore some recent modifications and extensions. In an era of sometimes sweeping economic change in developing countries, the relationship between agricultural prices and land degradation is of particular importance. I examine ways in which different models predict the likely land degradation effects of economic reforms.