Evaluating Soil Quality in Organic, Low-Input, and Conventional Farming Systems

Soil quality is an evolving concept intended to aid farmers, land managers, researchers, public decisionmakers, and others in the management of soil resources. The central question of soil quality assessment is “how does a soil function?” and a variety of physical, chemical, and biological indicators can be used to address it. This question, however, is complicated by the interdependencies between soil characteristics which often lead to trade-offs. Moreover, societal demands on soil resources are diverse and often contradictory, making soil quality a controversial topic. Nevertheless, examination of soil quality indicators can result in a better understanding of the effects of management activities on soil processes and the interactions among these processes. In this article we summarize current soil quality research at the Sustainable Agriculture Farming Systems (SAFS) project at UC Davis. We examine a variety of soil quality indicators and discuss their meaning within the context of sustainability (Table 1).