Abstract: Incubation experiments were made to study the effects of ammonium bicarbonate(AB), urea and modified ammonium bicarbonate(MAB) on N₂O emission from soil and NO₃^- formation in soil (under low(12%), normal(22%) and high (32%) soil moisture conditions). The results showed that the inorganic nitrogen fertilizers applied in fields were the important source of atmospheric N₂O. In most situations, MABnot only greatly delayed the occurrence of N₂O emission peak, but also reduced the amount of N₂O emission significantly (P<0.01), compared with ABand urea. In comparison with ABand urea, the amounts of N₂O emission were reduced by 80.23 and 88.41% (low moisture, 12%),40.00 and 27.59% (normal moisture, 22%) and little reduction and 45.88% (high moisture, 32%), respectively, during a period of 5 month incubation when MAB was applied. It is indicated that MAB was a promising Nfertilizer from the aspect of reducing N₂O emission from agroecosystem. The results also implied that applying MAB instead of AB which is used widely in China at present, might reduce the NO₃^- pollution of the underground water.

Key words: Ammonium bicarbonate(AB), Urea, Modified ammonium bicarbonate(MAB), N₂O emission rate, low-concentration CrylAc, cotton leaf roller, population growth, growth