M. REVATH1 AND K. VENKATESWARLU
Abstract
The impact of three pesticides, endosulfan, mancozeb and neem oil at 10, 25 and 50 ).J.g ml.' concentrations on autotrophic ammonium oxidation by nitrosofiers enriched from non-rhizosphere and rhizosphere soil samples from groundnut and foxtail millet was investigated. The nitrite-nitrogen released by nitrosofiers from ammoniacal nitrogen supplemented to the modified Winogradsky's medium was significantly less in enrichment cultures of non-rhizosphere and rhizosphere soil samples treated with all the three pesticides tested when compared with untreated controls. The present results suggest that the selected pesticides act as nitrification inhibitors besides controlling major agricultural pests.