Beyond the laboratory: performance and agreement of rapid methodologies for soil health assessment

Abstract. Soil health assessment increasingly relies on biological indicators because of their sensitivity and direct links to ecosystem functioning. However, conventional laboratory methods are time-consuming, require specialized infrastructure, and are often incompatible with rapid decision-making in applied contexts. Several rapid or field-deployable tools have recently been developed to address this limitation, but their comparability with standard laboratory methods remains insufficiently evaluated. Here, we compared four rapid approaches with their corresponding laboratory reference methods in a long-term grassland experiment: aggregate stability (SLAKES), soil respiration (portable CO2 analyzer), microbial biomass carbon and fungal-to-bacterial ratio (microBIOMETER®), and enzyme activities (Soil Enzymatic Activity Reader, SEAR). Agreement between methods was assessed using Spearman correlations, redundancy analyses and Procrustes analysis. Aggregate stability showed strong correspondence between rapid and laboratory measurements (R = 0.64), whereas soil respiration exhibited weak agreement, likely reflecting that in situ and laboratory approaches capture different aspects of respiratory activity. Microbial biomass carbon displayed moderate comparability between methods (R = 0.51), while fungal-to-bacterial ratios did not. Enzyme activities measured with SEAR were generally consistent with laboratory assays. Multivariate analyses indicated that overall, rapid methods captured ecological patterns similar to those revealed by laboratory protocols. These findings support the use of selected rapid tools as complementary or alternative options when laboratory facilities are unavailable or timely soil health information is required to inform management decisions.