A simple method for quantitative determination of ATP in soil

A simple method to measure soil ATP by the luciferin-luciferase system is described. The ATP is extracted from the soil by vigorous shaking with a sulfuric acid-phosphate solution for 15 min. An aliquot of the soil suspension is neutralized with a Tris-EDTA solution and mixed with a special ATP releasing reagent (NRB). ATP is measured after a 10 s exposure to the NRB reagent, followed by addition of luciferin-luciferase and integration over 10 s in a Lumacounter M 2080. The ATP content in soils which had been stored at 5°C for 90 days and then incubated at 25°C for 5 days, ranged from 0.37 to 7.52 μg ATP g^?1 dry wt, with standard deviations less than 10%. There was a close (r = 0.96) linear relationship between ATP content and biomass C determinated by fumigation for this group of soils. The soil biomass contained 4.2–7.1 μg ATP mg^?1 biomass C. The ATP content of the biomass declined during storage at 5°C for 210 days.