Scale issues in agroecological research chains

Abstract

Translating information about soil characteristics and qualities across different spatial and temporal scales has emerged as a major theme in soil science. The interest in scale has developed as our understanding of processes operating at scales larger (e.g. landscape, regional) or smaller (molecular, aggregate) than the field plot has increased. As next steps are considered in this area, an examination of the ecological literature presents some valuable philosophical and practical concepts pertaining to the translation of information across scales. The concepts of hierarchy and the holon are particularly relevant to the study of soil as a component of an ecosystem. The experience of the ecologists over the last 30 years suggests both opportunities and constraints for the study of soil systems at different spatial and temporal scales. As an example, our ability to predict soil processes at the small scale given large scale information (“down” scaling) is much worse than our ability to scale “up”. Moreover, while there have been several successful efforts to scale up certain types of information, we have been unable to predict large-scale phenomena given small scale information in several important instances. Ecological studies provide relevant insight. Different approaches to scale translation, and the successes and failures of these different approaches, have important implications for soil characterization and identification of land qualities as we address contemporary environmental problems at different scales. It is suggested that current scale translation efforts of all types fail for one of two main reasons; (1) either a key controlling process or characteristic has been overlooked, or (2) when multiple factors interact to create unique phenomena.