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| Petersen, Søren O.; Bol, Roland; Dittert, Klaus; Christofides, Calliopi; Roslev, Peter; Hansen, Martin N.. |
| Managed grasslands can accumulate soil organic carbon and thereby remove CO2 from the atmosphere. When grazed, however, the interaction between N inputs (fertilization, feeding, N fixation) and excretal returns can lead to sward deterioration and elevated emissions of N2O in urine patches. Both effects may reduce the positive effect of carbon storage on the greenhouse gas balance. A field plot study was carried out between 19 September and 4 October 2001, in which cattle urine amended with 13C- and 15N-labelled urea was added to a sandy loam pasture. Two levels of urea, corresponding to 23.3 and 39.8 g urea-N m-2, were compared with an unamended control. Ammonia losses corresponded to 14 and 12% of the urea-N applied in the low (UL) and high (UH) urea... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Air and water emissions. |
| Ano: 2004 |
URL: http://orgprints.org/2906/1/Ghent_presentation_020604.ppt |
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| Petersen, Søren O.; Roslev, Peter; Bol, Roland. |
| Within grazed pastures, urine patches are hot-spots of nitrogen turnover since dietary N surpluses are excreted mainly as urea in the urine. This short-term experiment investigated 13C uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g urea-C m-2. Confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0-5 and 10-20 cm depth was analyzed for content and composition of phospholipid fatty acids (PLFAs), and for the distribution of urea-derived 13C among individual PLFAs. Carbon dioxide emissions were quantified and the contributions derived from urea assessed. Initial changes in PLFA composition were greater at the lower level of urea, as revealed by a principal... |
| Tipo: Journal paper |
Palavras-chave: Soil biology. |
| Ano: 2004 |
URL: http://orgprints.org/4061/1/4061.pdf |
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