Challenges and Limitations in Soil Enzymology

Abstract Soil enzyme activities are widely recognized as valuable indicators of microbial functioning and biogeochemical cycling, as they support the transformation of organic matter and the mobilization of carbon, nitrogen, phosphorus, and sulfur. Notwithstanding the enzyme assays are used in soil quality studies, their ecological interpretation requires complementary approaches due to the complexity of soil biochemical processes. Soil enzyme activities derivate from different intra and extracellular enzyme pools and are involved in different metabolic pathways catalyzing substrate-specific reactions, suggesting that the assessment of one enzyme activity could limit the interpretation of entire biogeochemical cycles. The review does not underestimate the value of soil enzymology but highlights the need for methodological refinement and a more comprehensive interpretation of the complex soil system. Therefore, the development of soil enzymology could benefit by the inclusion of validated assays of enzyme activities involved in the main pathways of nutrient dynamics in soil with biomarker of the pathway the enzyme activity of the reaction limiting the pathway rate. Soil enzymology may also benefit by the implementation of knowledge about to soil spatial heterogeneity and enzyme stabilization within organo–mineral complexes. However, soil enzyme activities remain powerful tools for assessing potential microbial function, but recent advances in omics technologies offer opportunities to improve the knowledge about the microbial origins, genetic potential, and regulatory mechanisms. Moreover, integrating enzyme activities into process-based biogeochemical soil models represents a promising frontier for understanding and predicting nutrient dynamics, encouraging the development of integrated and innovative approaches.