In Search of the Holy Grail: Defining and Indexing Soil Quality.

In the early 1990s, there was a flurry of papers and book chapters attempting to define soil quality. Many of these papers included theoretical models for developing an index. Dr. John Doran was a leader in this effort, chairing the SSSA S-3 Soil Quality Working Group, co-editing two books on soil quality, and authoring or co-authoring numerous papers on soil quality into the early 2000s. John helped make the definition and concepts clear and concise as a member of a SSSA ad hoc committee on soil quality, which developed the now standard definition. Because some soil scientists had concerns about soil quality concepts, John participated in efforts to set the record straight with new publications addressing these issues.  The search for the elusive soil quality index, as proposed by John and others, is now becoming reality. Many proposed indices use single indicators or ratios. The Soil Management Assessment Framework is the culmination of work begun as a direct result of the “Defining Soil Quality for a Sustainable Environment” book, which John edited. This framework has been used by multiple researchers in the US and abroad at various scales, including use by USDA for the Conservation Effects Assessment project. It is also being adapted for use by the Natural Resources Defense Council. The Cornell Soil Health Assessment is a widely used suite of soil tests which also creates a soil quality index for farmers, loosely based on the SMAF. Early efforts toward a soil quality index began with theoretical constructs but today these indices have real world applications due to the ground-breaking work of Dr. John Doran.