Corrigendum to: Experimental validation of the Intergovernmental Panel on Climate Change default values for ruminant-derived methane and its carbon-isotope signature

Abstract

Two aspects regarding the ruminant's contribution to global methane (CH₄) emissions were investigated: (i) testing the accuracy of the Intergovernmental Panel on Climate Change default values for dairy cows fed different diet types and differing slurry storage temperatures; and (ii) providing carbon-isotope (C-isotope) signature data to contribute information on the characteristics of ruminant-derived CH₄ as global source. The experimental diets, fed to 18 dairy cows, were separated into forage-only (hay, C₃ plant) and forage-concentrate diets (barley, C₃ plant; maize, C₄ plant). Accumulated slurry was stored at either 14 or 27°C. The hay diet had the highest CH₄ conversion rate (Y_m 7.9%). Negligible amounts of CH₄ were emitted from slurries stored at low temperature. No diet effect was found at 27°C (~33 L/kg volatile solids). The isotope ratios of enteric CH₄ averaged -67.7‰ (C₃ plants) and -57.4‰ (C₄; maize). High temperature slurry storage resulted in different enrichment factors εCO₂-CH₄ for maize (33.2‰) and hay (35.9‰). Compared with the Intergovernmental Panel on Climate Change default values for Y_m and slurry CH₄ emission the results gained in the present experiment were higher and lower, respectively. Slurry-derived CH₄ was less depleted in ¹³C than enteric CH₄, which decreases the usefulness of this signature for global ruminant-derived CH₄.