Journal article
Lack of increased availability of root-derived C may explain the low N2O emission from low N-urine patches
Urine deposition on grassland causes significant N2O losses, which in some cases may result from increased denitrification stimulated by labile compounds released from scorched plant roots. Two 12-day experiments were conducted in C-13-labelled grassland monoliths to investigate the link between N2O production and carbon mineralization following application of low rates of urine-N.
Measurements of N2O and CO2 emissions from the monoliths as well as delta C-13 signal of evolved CO2 were done on day -4, -1, 0, 1, 2, 4, 5, 6 and 7 after application of urine corresponding to 3.1 and 5.5 g N m(-2) in the first and second experiment, respectively. The delta C-13 signal was also determined for soil organic matter, dissolved organic C and CO2 evolved by microbial respiration.
In addition, denitrifying enzyme activity (DEA) and nitrifying enzyme activity (NEA) were measured on day -1, 2 and 7 after the first urine application event. Urine did not affect DEA, whereas NEA was enhanced 2 days after urine application. In the first experiment, urine had no significant effect on the N2O flux, which was generally low (-8 to 14 mu g N2O-N m(-2) h(-1)).
After the second application event, the N2O emission increased significantly to 87 mu g N2O-N m(-2) h(-1) and the N2O emission factor for the added urine-N was 0.18%. However, the associated C-13 signal of soil respiration was unaffected by urine. Consequently, the increased N2O emission from the simulated low N-urine patches was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots.
Language: | English |
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Publisher: | Kluwer Academic Publishers |
Year: | 2006 |
Pages: | 91-100 |
Journal subtitle: | (formerly Fertilizer Research) |
ISSN: | 15730867 and 13851314 |
Types: | Journal article |
DOI: | 10.1007/s10705-006-9014-1 |