NITROUS-OXIDE EMISSION FROM GRASSLAND AND FOREST SOILS THROUGH NITRIFICATION

The present paper reports laboratory nitrification and nitrous oxide e mission in well-aerated soils of a Miscanthus sinensis dominated grass land and a Quercus serrata dominated warm temperate deciduous forest l ocated at Tokyo University's forest in mid-east Japan. This study anal ytically appraises the assumptions recognized recently regarding the g enesis of nitrous oxide in soil during the nitrification process. The nitrous oxide emission level gently ammonium fertilizer-treated acidic grassland forest soils (246 and 304 ng/g dry soil) compared to unamen ded respective soils. This rise in nitrous oxide emission sharply boos ts up after lime addition when the pH is raised to 7.4 in the same N-f ertilized acidic grassland and forest soils (3451 and 883 ng/g, respec tive dry soils). These results have direct implications on use of ammo niacal fertilizers to raise the agricultural productivity. Sizable par t of the Indian soils is alkaline, well drained, with low moisture. Ni trous oxide emission from such soils during nitrification of fertilize r N may be significant in relation to the potential threat of fertiliz er-derived nitrous oxide to the stratospheric ozone layer.