Environmental indicators offer a simple measure of the status of an environmental attribute. Examples include indicators of potential damage, such as toxic emissions, as well as indicators of potential benefits, such as biodiversity. Environmental indicators can be used in trade-off analysis.

Introduction to Agro-Environmental Indicators
This helpful introduction to the general topic of environmental indicators for agriculture comes from Environment Canada.

Specific environmental indicators
Many different specific environmental indicators are available. This page provides links to indicators of soil erosion, pesticide toxicity, and other indicators.