A modified method for measuring soil hydroxylamine reductase activity

In this paper,the traditional measuring method of soil hydroxylamine reductase activity was partially modified.The anaerobic condition needed for the measurement was created by a 3-5 cm fluid seal,which was made from the boiled water having been cooled down under airproof condition.The air above the fluid seal was exhausted with N2 current to prevent O2 dissolving into water.Compared with traditional methods,this method could reduce the uncertainty and the complexity in operation,and increase the maneuverability.Taking iodometric analysis as the reference,four spectrophotometric methods were adopted to determine the hydroxylamine concentration in extract,and the results showed that ammonium ferric sulfate-phenanthroline method was of high accuracy and precision,being feasible in measuring soil hydroxylamine reductase activity.