Estimating on-farm methane emissions for sheep production on the Northern Tablelands: establishment of demonstration site

Abstract

A 36-hectare demonstration site at Armidale on the Northern Tablelands of New South Wales has been established to give livestock producers a practical insight into the magnitude of carbon fluxes, especially methane (CH4), associated with crossbred lamb production. The site contains soil and topographical diversity typical of the region (pH 4.8–5.1 (1:5 CaCl₂); soil organic carbon 1.2–3.8%; cation exchange capacity 3–41 meq/100g). The replicated study over two years will compare animal productivity and emissions of low stocking rate enterprises on a low fertility (hill) section of the site (3.7 DSE/ha) with those of high soil fertility enterprises on the more fertile alluvial flats (6.7 DSE/ha). An EM38 soil map and seven soil samples were used to characterise the soil diversity within the two landscapes and to block each landscape into three classes (A, B, C), with three paddocks/class. Monthly pasture (green and dead DM availability) and regular production data (liveweight gain, fat score, fecundity, wool and lamb carcass weights at slaughter) will be collected. These measures will be used in decision support tools to estimate total on-farm CH₄ emissions, emission per unit product, and to conduct a life cycle analysis of the contrasting enterprises. It is intended to use the site as a regional reference point for effective integration of farm carbon, productivity and economic understandings.