Developing a multifunctional indicator framework for soil health

• The soil health indicator framework reports on the delivery of multiple ecosystem services rather than an aggregate metric. • Trade-offs between ecosystem service delivery by soil is possible at different spatial scales for a range of end users. • The framework can be updated by adding new data, expert or local knowledge, and refining the underlying conceptual models. We developed a proof-of-concept indicator framework to monitor soil health based on the delivery of ecosystem services. Instead of distilling soil health to one metric, the framework enables simultaneous comparison of the delivery and trade-offs between different ecosystem services that are delivered by soils, accounting for inherent capability determined by soil type and land use. The framework has potential to explore a whole systems approach, ascertaining soil system response in real time that can detect emergent properties of the system. Initial development of the framework ranked salient soil properties known to be linked and pertinent to the delivery of ecosystem services. These key soil properties, together with other environmental variables were used to create simple conceptual models representing a causal network for soils’ contributions to the ecosystem services of climate regulation, food production, water regulation and below-ground biodiversity. The conceptual models were developed into Bayesian Belief Networks populated with relevant national data and expert judgement. The resulting outputs gave an indication of how well (i.e. healthy) a soil can deliver each ecosystem service at a land parcel scale presented in a dashboard app. The output at a specific location can be contextualised or benchmarked against to the range of values for areas with similar soil and land use types. The idea was to build the model with readily available data and knowledge but with flexibility for iterative development to refine the framework and models and improve outputs over time. This enables indicator updates using inputs of local knowledge of land management, or when additional soil data becomes available, or when soil policy drivers change, or our understanding of the conceptual and statistical models are improved. The indicator framework can be applied and adapted for use in multiple contexts from reporting national policy targets on soil health to determining soil health for a farmer at the field level.