Agronomic performance, herbage quality, methane yield and methane emission potential of pasture mixtures

Guangdi Li; Matthew Newell; Suzanne Boschma; Richard Meyer; Jennifer Wood; Warwick Badgery; Richard Hayes

Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Agronomic performance, herbage quality, methane yield and methane emission potential of pasture mixtures

Guangdi Li , Matthew Newell , Suzanne Boschma , Richard Meyer, Jennifer Wood , Warwick Badgery , Richard Hayes

Abstract

Context: Enteric methane (CH4) emission from livestock accounts for 71% of greenhouse gas (GHG) emissions from Australian agriculture. Aims: To evaluate a range of pasture mixtures using species with anti-methanogenic properties for their compatibility, productivity, feed quality and CH4 emission reduction potential. Methods: Two field experiments were conducted at Wagga Wagga and Cowra, NSW Australia from 2022 to 2024. A total of 33 pasture mixtures were evaluated over 3 years. Herbage was taken in spring from each pasture mix to analyse mineral composition, feed quality, plant secondary compounds and CH4 yield from in vitro fermentation. Key Results: Methane yield was negatively correlated with saponins and condensed tannins. Perennial herbs, particularly plantain, had higher concentrations of condensed tannins and saponins than perennial grasses at both sites. Overall, balansa clover was the species with the highest concentration of condensed tannins and biserrula had the highest concentration of saponins. However, plantain and biserrula lacked persistence at both sites. Chicory-based pastures were highly productive with high feed quality. Conclusions: Pasture species higher in saponins and condensed tannins have great potential to reduce enteric CH4 emissions. Pasture mixtures containing plantain and/or biserrula exhibited potential to reduce CH4 emissions, but poor persistence may limit their adoption in some environments. Implications: The study provides evidence that a number of highly productive pasture mixtures have potential to reduce CH4 emission intensity and can be deployed within extensive livestock grazing systems, allowing producers opportunity to decrease their GHG liability in emission reduction schemes.

CP24356 Accepted 06 March 2025