Effect of Inorganic N Composition of Fertilizers on Nitrous Oxide Emission Associated with Nitrification and Denitrification |
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| Authors: | Kazuhira Yokoyama Tohru Ohama |
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| Institution: | Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, 753–8515 Japan |
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| Abstract: | 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 × 103 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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| Keywords: | denitrification inorganic N nitrification nitrifier denitrification nitrous oxide |
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