Built Biological: Indicators at the Intersection of Resources, Environmental Limits and Ecosystem Function in the Willamette Valley, OR

The science of soil health increasingly reflects the idea that soils are living ecosystems with inhabitants that influence, and are influenced by, their environment. The suite of properties used in the USDA-NRCS Dynamic Soil Properties for Soil Health (#DSPs4SH) project are indicators that change on timeframes pertinent to human activity. This framework has strong potential as a tool for leveraging scientific inquiry toward solutions for land managers. However, many of these indicators must be calibrated to be interpretable across variable soils. In the Willamette Valley, Oregon, Dynamic Soil Properties for Soil Health study, we measured Dynamic Soil Properties in three management systems in an extensive benchmark soil series. We sampled soil from vineyards, Christmas tree farms and second-growth timber stands on the Jory series (Palehumults). Previously, we found that soil carbon indicators, taken together, indicated complex dynamics between nutrient availability, demand and activity. For instance, permanganate oxidizable carbon (POXC) was correlated to soil organic carbon and carbon mineralization rates, but we found limited evidence that it represents a particularly active form of carbon. In this presentation we will build upon this work to characterize function more accurately in our soils. We measured a suite of potential extracellular enzyme activities using standard methodology and assessed them on their ability to 1) detect differences in management strategies, 2) characterize relevant soil functions and 3) reflect the nutrient demand of the microbiome in context with other biological indicators. Finally, we suggest a conceptual model for interpreting these indicators on a holistic and quantitative basis to visualize ecosystem function.