A REPORT by the Tasmania Institute of Agriculture has found that the most cost-effective way for livestock businesses to achieve net-zero is by implementing multiple strategies.

While there has been a lot of research on the effectiveness of methods to reduce greenhouse gas (GHG) emissions, this report focussed specifically on how different interventions impacted productivity, profitability and emissions of the beef and sheep industries.

It looked at several practices aimed at reducing or removing GHG emissions:

• Improving soil carbon storage by grazing management and pasture renovation
• Improving carbon storage in vegetation by planting native tree species
• Improving livestock feed conversion efficiencies
• Adopting anti-methanogenic feed additives, such as Asparagopsis or biochar, and
• Revenue diversification with renewable energy or irrigation to reduce dependence on rainfall for income.

Lead author Professor Matthew Harrison said the easiest option was also the most costly, while the more difficult changes were the most lucrative, with the cost of transitioning to net-zero in the latter case improving profitability.

The report worked with a regional reference group of industry practitioners and used data from two farms in southern Australia to ensure relevance, credibility and legitimacy of proposed interventions.

The study found that few interventions enhanced profitability and reduced GHG emissions, but costs of transitioning to net-zero were lower when appropriate interventions were stacked and boosted productivity.

“To get to net-zero in a profitable way – you would need to improve livestock feed conversion efficiency, reduce enteric methane through anti-methanogenic feed additives and sequester carbon through planting native trees,” said Professor Harrison.

“You have got to have all three to get to net-zero in a profitable way.

“The intervention with the lowest social licence – continuing the status quo and purchasing carbon credits to offset emissions was the most expensive pathway to transition to net-zero.

“I cannot see farms doing that to negate all of their GHG emissions, although it may be necessary to offset some remaining emissions that cannot be negated through other interventions in the business.”

Profit vs emissions reduction

The report found anti-methanogenic feed supplements and planting trees had the greatest impact on emissions abatement, while revenue diversification with wind turbines and adoption of livestock genotypes with enhanced feed conversion efficiency were best for improving profit.

In particular, those interventions that resulted in a productivity co-benefit (ie improvement in liveweight gain or wool production) were often the most profitable.

Ways to reduce GHG emissions for the livestock sector. Source: Tasmania Institute of Agriculture.

Here are some more in-depth findings from the report:

NOTE: the study assumed farmers would be paid $28/tonne CO₂ reduced or removed and taxed $80/tonne CO₂ that increased above baseline levels (the latter known as the social cost of carbon).

Feed additives

Individual interventions targeting livestock enteric CH₄ (CH₄ produced by fermentation in the gut) were most promising for reducing GHG emissions, such as the seaweed feed additive Asparagopsis taxiformis.

Asparagopsis feed additive reduced farm enterprise CO₂ by 46–72percent under future climates. However, this was also one of the most expensive singular interventions, reducing profits by $23–25tonne CO₂ mitigated.

The regional reference group considered biochar feed supplementation as highly adoptable based on ease of implementation in comparison with other interventions.

The study showed that biochar feed supplementation reduced net GHG emissions by 8pc and increased profit of the cattle enterprise by 18pc, but reduced profit of the sheep enterprise by 10pc.

The studies do not account for upstream (pre-farm) GHG emissions associated with biochar production, which may reduce perceived climate benefits at the farm scale.

In contrast, interventions that were considered most adoptable by the group of expert practitioners often had the lowest mitigation potential.

Revenue diversification

Purchasing a farm in a distinctively different climatic zone and altering lambing or calving times accordingly evoked the greatest improvement in productivity (16–18pc), while enterprise diversification (capital investment to enable income generation from irrigated grapevines or wind turbines), pasture renovation with deep-rooted legumes and improvements in animal genetic feed-conversion efficiency were most conducive to improved profit (17–39pc).

Improving feed conversion efficiency

Improving liveweight gain per unit of feed consumed was operationalised by increasing pasture utilisation.

This increased profit $70–250 tonne CO₂ but only had modest impacts on productivity (0–6pc increase) and GHG abatement (−9 to 15pc reduction).

Improving feed conversion efficiency through genetics increased livestock production and profit by 8–39pc while reducing net GHG emissions by 11–17pc.

Planting trees

Planting trees on farm decreased profits for each unit of CO₂ mitigated compared with incorporating lucerne into pastures.

This occurred because lucerne enabled pasture growth and improved livestock production, whereas planting trees was assumed to represent a new investment or occur within remnant vegetation, with no effect on livestock production.

This assumption was made for conservatism, acknowledging that some tree species could provide productivity co-benefits via provision of forage, shelter or pasture production co-benefits.

Conclusions

The report found stacking several interventions to mitigate enteric methane, improve feed conversion efficiency and sequester carbon – entirely negated enterprise emissions in a profitable way.

Professor Harrison said that one of the simplest ways to reduce emissions intensity (emissions per unit production) was to improve production efficiency.

“That could be done by reducing juvenile or adult mortality, culling unproductive animals, and focussing on avenues to fatten up young animals and remove them from the farm enterprise earlier than that conducted historically,” he said.

“There is no one size fits all. Focus on the aspect of the enterprise in most need of improvement – whether that be soil fertility, feed conversion efficiency or planting native trees on unproductive land.”

You can read the full report here.