Studies of shifting cultivation and other slash-and-burn systems over the past 30 years have basically confirmed the conceptual model of carbon and nutrient cycling put forth by Nye and Greenland. The model stresses that soil biological processes should not be viewed in isolation but as an integral part of the system. There has been some progress in refining certain aspects of the model but most studies have merely provided more numbers for specific fluxes or pools in the cycle rather than the entire cycle. While these studies have reinforced the model of Nye and Greenland, they have not added much to understanding the controls or improving the predictive capacity that would allow improved management of slash-and-burn systems. Future studies should concentrate on controlling and manipulating certain components in the system and looking at the resulting changes in the other pools and processes in the system. Results from these types of studies can be combined with system models for simulating and comparing different management strategies.