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| Titel |
Trace gas emissions following deposition of excreta by grazing dairy cows in eastern Canada |
| VerfasserIn |
P. Rochette, D. E. Pelster, M. H. Chantigny, D. A. Angers, C. Liang, G. Belanger, N. Ziadi, E. Charbonneau, D. Pellerin |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250064491
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| Zusammenfassung |
| The N2O emission factor proposed for cattle excreta N by the Tier I IPCC methodology
(EF3) is 2% (IPCC, 2006). While N2O emissions from excreta deposited by grazing animals
have been reported in several publications, relatively few estimated EF3 values because
measurements did not cover the entire year. This study measured N2O and CH4 flux and crop
dry matter (DM) yield over two years (2009 to 2011) from a clay and a sandy loam soil
cultivated with Timothy grass (Phleum pratense L.). A split-plot design was used on each soil
type, with different application dates (either spring, summer or autumn application) as main
plots and treatment (U-50: urine 50 g N m-2, U-100: urine 100 g N m-2, dung: 60
g N m-2, and control) as the sub-plots. Regardless of application time, annual
DM yield increased in all treated plots when compared to the control. Also, DM
yields were generally greater when urine as opposed to dung was applied suggesting
greater N-availability from the urine application. The CH4 flux from the dung plots
increased for only the first two weeks after treatment while the flux from the urine
plots was similar to the control plots. Cumulative N2O emissions on the U-50 and
U-100 plots increased linearly with urine N rate on both soils, resulting in nearly
identical mean emission factors for both urine rates. The emission factor for the urine
was three times greater on the clay (1.02% of applied N on both rates) than on the
sandy loam soil (0.26% (U100) and 0.31% (U50) of applied N). Cumulative N2O
emissions from dung plots also differed between soil types; however the impact
of soil type on N2O emissions was opposite to that of urine, with greater losses
from the sandy loam (0.15%) compared with the clay soil (0.07%). These results
suggest that estimates of soil N2O emissions by grazing cattle in Eastern Canada
obtained using the IPCC default methodology are overestimates of actual values
and that these estimates for should include a stratification according to soil type. |
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