Juggling profit, climate, greenhouse gas emissions and biodiversity: the livestock farmer's conundrum

<p>armers must maintain profitability to persist, while juggling other challenges like climate change, greenhouse gas (GHG) emission reduction and biodiversity. The need for innovations that boost productivity, profitability and biodiversity while slashing GHG emissions has never been higher. Companies in the value chain are setting targets to cut GHG emissions from farms. Under the Treasury Laws Amendment Act 2024, all agricultural value chain companies will need to report on their greenhouse gas emissions by 2027, including the farms that supply them with product. However, these GHG emissions are typically on the basis on which they purchase (e.g. mass or volume), that's being emissions intensity (t GHG/t product), this gives farmers far more options to respond, as it is just about improving farm production efficiency. Reductions in emissions intensity can be achieved by (1) reducing GHG emissions while maintaining production, (2) increasing production while maintaining GHG emissions or ideally (3) reducing emissions while increasing production. The greatest reductions in emissions intensity often align with improving farm production and efficiency strategies such as improved weaning rates or greater liveweight gain of young animals. This project conducted GHG audits on 13 beef and sheep farms across Australia. The project explored mitigation options including tree planting, supplementation with feed additives, methane reducing legumes and improving LWG through better quality feed. The farmers also nominated options that were of interest and relevance, including pasture and soil fertility improvement, improved lambing times and weaning rates, changing herd/flock size, using organic compost versus nitrogen fertiliser. The interventions chosen reflected the diversity in enterprises, environments, interests and business goals of farmers involved. Several interventions increased absolute GHG emissions and/or emissions intensity. However, these interventions also remained more profitable than the baseline farm systems, even after placing a ‘carbon tax’ on the relative increase in GHG emissions. Improving soil organic matter (SOM) had multiple productivity and sustainability benefits over the long term. While soil carbon is around 58% of soil organic matter, soil organic carbon (SOC) per se does not confer the productivity benefits (i.e. nitrogen mineralization, soil buffering capacity and water holding capacity); instead, it is the SOM that provides physical, chemical and biological benefits to plants. Overall, planting native vegetation had significant biodiversity benefits, but this benefit was not realised for at least three decades after trees were planted. For example, threatened species habitat, as a percentage of the area planted to trees, increased by 43-353% in the 30 years after planting trees. We conclude that metrics of assessment are important when assessing purported improvements in sustainability: governments are focused on total GHG, supply chains are focused on emissions per unit of meat and/or wool production (EI), and Farmers should be focused on reducing GHG relative to farm GHG in previous years (relative reductions). The greatest EI reductions, improvements in profit and biodiversity gains come from targeting underlying site-specific inefficiencies and combining options (e.g. trees and legumes). Planting trees had significant benefits for biodiversity, but this benefit took two-three decades after trees are planted to occur, while Carbon benefits from trees are greatest 10-20 years after trees are planted, then diminish thereafter.</p>