Effect of inorganic N composition of fertilizers on nitrous oxide emission associated with nitrification and denitrification
2005
Yokoyama, K.(Yamaguchi Univ. (Japan). Faculty of Agriculture) | Ohama, T.
We studied the effect of repeated application (once every 2 d) of a fertilizer solution with different ratios of NH4(+)-and NO3(-)-N on N2O emission from soil. After the excess fertilizer solution was drained from soil, the water content of soil was adjusted to 50% of the maximum water-holding capacity by suction at 6 x 10(3) Pa. Repeated application of NH4(+)- rich fertilizer solution stimulated nitrification in soil more than NO3(-)-rich fertilizer. Although the evolution of N2O through nitrifier denitrification tended to increase with the repeated addition of a fertilizer solution rich in NH4(+) rather than in NO3(-), the contribution of nitrifier denitrification remained at levels of 20 to 36% of the total emission regardless of the inorganic N composition. The total emission of N2O also tended to increase with the application of NH4(+)-rather than NO3(-)-rich fertilizer. It was suggested that the coupled process of nitrification and denitrification at micro-aerobic sites became important when fertilizer rich in NH4(+) was applied to soil under relatively aerobic conditions.
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