The Missing Link: A Purpose-Led Framework for Assessing Soil Health

Human food supply depends on healthy soils yet lack of metrics to estimate returns from soil health-improving practices (SHIPs) limits their adoption at ecologically significant scale. To address this limitation, we evaluate a purpose-led framework that evaluates tradeoffs between food production and other ecosystem services. “Proof of concept” evaluations of corn-based systems in the central USA estimated returns from adoption of no-till in Kentucky and subsurface drainage in Iowa. No-till returned $172 ha-1 yr-1 from improved nitrogen (N) and water availability associated with increased soil organic carbon (SOC), which increased N fertilizer efficiency and yield. Drainage returned $75 ha-1 yr-1 from greater soil N and water supply in an enlarged aerated root zone, which increased N fertilizer efficiency and yields while decreasing greenhouse gas emissions despite a reduction in SOC. Soil N and water supply were useful indicators of soil health in both cases, which should be broadly applicable to cereal systems worldwide.