Protocol for indicator scoring inthe soil management assessmentframework (SMAF)

Assessment tools are needed to evaluate agronomic management effects on critical soil functions such as carbonsequestration, nutrient cycling and water partitioning. These tools need to be flexible in terms of selection of soil functionsto be assessed and indicators to be measured to ensure that assessments are appropriate for the management goals. The soilmanagement assessment framework (SMAF) is being developed to meet this need. The SMAF uses soil physical, chemicaland biological indicator data to assess management effects on soil function using a three-step process for (1) indicatorselection, (2) indicator interpretation and (3) integration into an index. While SMAF is functional in its present format, it isintended to be malleable so that user needs can be met. Development of additional indicator interpretation scoring curvesis one way that this framework can be expanded. Scoring curve development is a multi-step process of identifying anindicator, determining the nature of the relationship of the indicator to a soil function, programming an algorithm and/orlogic statements describing that relationship and validating the resulting scoring curve. This paper describes the stepsinvolved in developing an SMAF scoring curve. Scoring curves for interpreting water-filled pore space (WFPS) andMehlich extractable potassium (K) were developed using the described protocol. This protocol will assist users of the SMAFin understanding how the existing scoring curves were developed and others interested in developing scoring curves forindicators that are not in the current version