Nitrogen transformations of ammonium sulfate and alanine in submerged Maahas clay |
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| Authors: | Ireneo J Manguiat Tomio Yoshida |
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| Institution: | 1. The International Rice Research Institute , Los Ba?os , Laguna , Philippines;2. College of Agriculture, University of the Philippines , Los Ba?os , Laguna , Philippines;3. P. O. Box 583, Manila , Philippines |
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| Abstract: | The fate of added nitrogen in submerged soils was studied using 15N-labelled ammonium sulfate and alanine. After 8 weeks of incubation 25 and 22%, respectively, of nitrogen from ammonium sulfate and alanine were recovered in the soil. Under the experimental conditions used nitrogen added to presubmerged soils was lost rapidly outside of the soil-water system, regardless of whether the nitrogen was organic or inorganic. Fractionation studies revealed that the amount of tagged N incorporated into exchangeable ammonium, residual fractions, volatilized as NH3 and chemically fixed nitrogen was not enough to account for the nitrogen loss. The nitrogen loss was attributed to nitrification and subsequent denitrification during the incubation period. The effect of N-Serve 2-chloro-6-(trichloromethyl)pyrimidine] on nitrification of 15N-labelled (NH4)2SO4-in submerged soils was studied. About 15% more nitrogen was recovered from non-presubmerged soils, and less nitrate was accumulated in presubmerged soils where N-Serve coated (NH4)2SO4 was applied, than from soils where (NH4)2SO4 was applied without N-Serve. Presubmerged soils provided a more favorable environment for nitrification than for denitrification under the experimental conditions used. |
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