Results of a 10-year decomposition experiment indicated that the annual mineralization rate of organic N in newly-formed humus varied with the type of original plant materials and the water regimes for decomposition,ranging from 0.028 to 0.074.The mineralization rate under waterlogged conditions was higher than that under upland conditions.The proportion of α-amino acid N in humus newly-formed under waterlogged conditions was slightly higher than that under upland conditions.It decreased gradually with time,while the proportion of nonhydrolyzable N showed no consistent trend,irrespective of the water regines for decomposition.The distribution of amino acids in humus newly-formed from different plant materials under various water regimes was quite similar with that in original plant materials,and only minor differences could be found among them.For example,in comparison to original plant materials,the newly-formed humus contained higher proportions of isoleucine,cysting,γ-amino-butyric acid and ornithine,and lower proportions of phenylalanine and proline.Moreover the proportion of phenylalanine was higher in the humus newly-fored under waterlogged conditions than that under upland conditions.
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