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 quantifies tradeoffs between food production and other ecosystem services. “Proof-of-concept” evaluations of corn-based systems in the central United States estimated returns from adoption of no-till in Kentucky and subsurface drainage in Iowa. No-till returned $172 ha⁻¹ year⁻¹ from improved soil N and water supply, which was associated with greater soil organic carbon (SOC), increased N fertilizer efficiency, and yield. Drainage returned $75 ha⁻¹ year⁻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. SHIPs that impact soil N and water supply had a large influence on profitability and resource use efficiency, which makes them useful soil health indicators, and this finding should be broadly applicable to rainfed, upland cereal systems worldwide.