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Incorporation studies of NH + 4 during incubation of organic residues by l5 N‐CPMAS‐NMR‐spectroscopy
Author(s) -
KNICKER H.,
LÜDEMANN H.D.,
HAIDER K.
Publication year - 1997
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.1997.tb00209.x
Subject(s) - chemistry , lignin , nitrogen , incubation , amide , nuclear magnetic resonance spectroscopy , ammonia , straw , nuclear chemistry , organic chemistry , inorganic chemistry , biochemistry
Summary This study focuses on the processes occurring during incorporation of inorganic nitrogen into humic substances. Therefore rye grass, wheat straw, beech saw dust, sulphonated lignin and organosolve lignin were incubated together with highly 15 N‐enriched ammonium sulphate in the laboratory for 600 days. Samples from the incubates were periodically analysed for weight loss, and carbon and nitrogen contents. The samples were also analysed by solid‐state 13 C‐ and 15 N‐CPMAS‐NMR‐spectroscopy to follow the turnover of the materials during incubation. Most of the detectable N‐signals was assigned to amide ‐ peptide structures. The remaining intensities could be ascribed to free and alkylated amino groups, and those on the low field side of the broad amide‐peptide signal to indole, pyrrole and nucleotide derivatives. Abiotic reactions of ammonia with suitable precursors and the formation of pyridine, pyrazine or phenyloxazone derivatives were not observed. Signals from ammonia and nitrate occurred only at the end of the incubation.