In response to increasing concerns about the degradation of natural resources and the sustainability of agriculture, many research programmes have been established in natural resource management (NRM). However, although methods for evaluating the impacts of crop improvement technologies are well developed, there is a dearth of methods for evaluating the impacts of NRM interventions. This is partly due to the complexity of interactions among natural resources, spatial and temporal dimensions of impact, and the valuation of direct and indirect environmental costs and benefits.