Harmonizing soil health assessment: converging indicators but divergent evaluation methods

Recent European initiatives, including the Soil Monitoring Law and Mission Soil, increasingly require harmonized soil health assessment frameworks. However, it remains unclear whether current scientific approaches provide sufficient methodological convergence to support such harmonization. Based on a targeted Scopus search and manual classification of 62 peer-reviewed studies published between 2008 and 2026, we show that convergence is emerging in conceptual framing and indicator selection, but not in the procedures used to benchmark, combine, and interpret indicators. The analysis covered conceptual dimensions, indicator-category frequencies, co-occurrence patterns, and reported aggregation or evaluation procedures. Indicator-based approaches occurred in 94% of the reviewed studies, and a recurrent physico-chemical assessment core emerged across the literature. Function / ecosystem based and policy-oriented perspectives occurred in 87% and 65%, of studies, respectively. In contrast, evaluation procedures remained heterogeneous, with threshold-based benchmarking representing the most common configuration. Explicit aggregation or evaluation procedures were identified in 42 studies, and 14 of this use threshold logic. This asymmetry creates a critical gap between monitoring and assessment. While common indicators are becoming available, there is still no widely accepted framework for translating measurements into comparable evaluations of soil health. We suggest that future harmonization efforts should focus less on identifying new indicators and more on developing transparent and reproducible principles for aggregation, benchmarking, and interpretation capable of integrating ecological and policy-relevant dimensions of soil health.