A keystone microbial enzyme for nitrogen control of soil carbon storage

Third, standard deviations and replicates had to be reported or could be derived from the results. Fourth, details on N addition methods (rate, frequency, form, and duration) had to be provided. We identified 40 papers that met these criteria.

For each study, we recorded linginase and cellulase activities, site location (longitude and latitude), climatic variables (mean annual precipitation (MAP), mean annual temperature (MAT)), elevation, background N deposition (BND), vegetation and soil types and N addition methods (rate, duration, frequency and form of N addition). If these data were not reported, we contacted the corresponding author for more information.

Otherwise, we obtained MAT and MAP from WorldClim Database (worldclim.org/), BND from Global N deposition database (webmap.ornl.gov/), vegetation types from the Whittaker Biome Diagram, and soil types from FAO classification (fao.org/soils-portal/soil-survey/soil-classification/usda-soil-taxonomy/en). Where available, we also tabulated plant productivity, soil pH, soil C:N, microbial abundance, soil texture and recalcitrant C pool.