Table 1 Glossary of terms as used in this study
From: Revisiting enteric methane emissions from domestic ruminants and their δ13CCH4 source signature
Terms | Units | Explanations |
|---|---|---|
δ13CCH4 | ‰ | The 13C isotopic signature of methane; i.e., the 13C/12C-ratio of CH4 expressed in δ-notation relative to Vienna Pee Dee Belemnite (VPDB)-standard |
δ13CCH4-atm | ‰ | The 13C isotopic signature of atmospheric methane |
δ13CCH4-sources | ‰ | The 13C isotopic signature of methane from different source types, such as microbial sources, fossil-fuel sources, and biomass burning |
δ13CCH4-ruminant | ‰ | The 13C isotopic signature of ruminant enteric fermentation methane emissions |
δ13Cdiet | ‰ | The 13C isotopic signature of ruminant diet |
DM | kg | Dry matter |
ECH4 | MJ (kg CH4)−1 | The energy content of methane |
EGE | MJ (kg dry matter)−1 | The gross energy content of feeds |
FCH4-ruminant | Tg CH4 yr−1 | The annual ruminant enteric fermentation methane emissions |
FCR | kg dry matter (kg live-weight gain or kg eggs production)−1 | The feed conversion ratios |
fdressing | % | The dressing percentage of livestock |
fintensity | % | The farming intensity |
fDE | % | The digestible fraction of gross energy contained in feeds (i.e., an indicator of digestibility) |
GE | MJ | The gross energy intake/requirement by ruminants |
ME | MJ | The metabolizable energy intake/requirement by ruminants |
Q | kg dry matter | The total feed quantity used for different animal types |
REM | % | The fraction of digestible energy available in diet used for maintenance |
Weight | kg live-weight gain or kg eggs production | The total live weight of slaughtered animals or total weight of eggs production |
Ym | % | The methane conversion factor |
