Functional Soil Biological Measurements to Support Healthy Soils

Soil microorganisms contribute significantly to terrestrial ecosystem functioning through their activities. Various methods exist to characterize soil microbial activity and functional diversity including those that focus on potential enzyme activities and the respiratory responses of microbes to different substrates. Here, we describe: (1) the fluorescein diacetate hydrolysis assay for total potential microbial enzyme activity; (2) measurement of beta-glucosidase activity using ρ-nitrophenyl (pNP); (3) multienzyme assay using 4-methylumbelliferone (MUB); and (4) MicroResp assays to measure the respiratory responses of microbes to different substrates and generate a community level physiological profile (CLPP).