Chemical decomposition and fixation of nitrite in acidic pasture soils and implications for measurement of nitrification

Abstract

The fate of added 15N-labelled nitrite (15NO2--N) was investigated in a laboratory experiment with two acidic pasture soils collected from northeast Victoria (Maindample and Ruffy) and an alkaline soil collected from Waurn Ponds, Victoria, Australia. Two and a half hours after mixing and extraction, the 15NO2--N recovered in 2 M KCl extracts was 22% and 33% of the applied NO2- in Maindample and Ruffy soils, respectively, and 100% in the Waurn Ponds soil. There was no difference in NO3- recovered with and without NaClO3 addition during this procedure, suggesting that biological oxidation of the applied NO2- was not the cause of the low recovery. Of the applied 15NO2--N, 21% and 20% in the aci..