The art and science of comparing and evaluating soil resources are nearly as old as the discipline of Soil Science, but until the 1980’s, the emphasis was almost exclusively on naturally occurring or inherent soil properties. During the past 20 years, soil quality assessment has primarily been focused on dynamic soil properties and processes. Several different approaches for soil quality assessment have been offered, differing primarily with regard to their intended use, desired accuracy and precision, and analytical or technical sophistication. For all approaches and as a distinguishing feature from traditional soil survey and evaluation, these assessments emphasize soil physical, chemical, and biological response to recent and current soil management practices. Advantages and disadvantages of visual soil quality assessments, scorecards, test kits, analytical measurements, use of pedo-transfer functions, scoring functions, and computer simulation will be reviewed. Overall, the assessment purpose (i.e. education, improved soil management, or policy decisions), temporal and spatial scale, requirements for precision and accuracy, and cost are the primary drivers for which assessment approach to use. Soil quality assessments using the various approaches are being used throughout the world. Visual assessment and test kits are being used primarily for hands-on training. Analytical assessments are now being offered by some soil-test laboratories. Soil quality assessment has been incorporated into the CEAP (Conservation Effects Assessment Project) and is being used to evaluate sustainability of harvesting crop residues for agro-fuels and other products in lieu of leaving the materials on the soil to sustain several critical functions. The future for soil quality assessments will be demanding as humankind balances challenges associated with food, feed, fiber, and now energy production from a finite and dwindling resource.
Link to Presentation (pdf; 1MB)
Douglas Karlen - Douglas L. Karlen, USDA-ARS Supervisory Soil Scientist & Research Leader for the Soil & Water Quality Unit at the National Soil Tilth Laboratory has degrees from the University of Wisconsin – Madison, Michigan State University, and Kansas State University. He is author or co-author for more than 260 technical publications. His research focus is on assessing sustainability of agricultural practices by examining their impact on chemical, physical, and biological indicators of soil quality. He is chair-elect for the North Central Sustainable Agriculture Research and Education Administrative Council and currently co-chairs the Renewable Energy Assessment Project (REAP) team for the USDA-ARS. A Fellow within the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Doug also serves as Assistant Secretary General for the International Soil and Tillage Research Organization (ISTRO) and was the 2007 recipient of the Conservation Award at this year’s Soil & Water Conservation Society meeting.