Not enough carbon to spare: Don't risk selling your farm's share

In fact, selling credits for soil carbon sequestration is unlikely to have much of a long term future in Australia anyway, according to the University of Melbourne's Professor Richard Eckard.

Our dry- to drought-prone soils generally cannot absorb and sustain carbon in significantly greater quantities over long periods.

Given the sequestration process relied on rainfall for 70 per cent of the soil's carbon capacity, soil carbon credits were likely to have declining appeal and value to big businesses trying to counterbalance their own annual greenhouse gas emissions.

"Reducing your farm's methane emissions is probably a much safer bet," he said.

Professor Eckard has told farmers to keep as much carbon as they can possibly sequester within their own fence boundaries, or risk being ignored by supply chain buyers after 2030.

He also warned Australia was running a risk of massive and sudden land use change if big emitters like mining companies continued buying farmland to convert to vast tree plantings or regrowth areas so they could sequester carbon to counterbalance their own emissions.

"If we plant trees over the West Australian wheatbelt, that's the end of that industry," he said.

He also observed a permanent vegetation cover across the 4.5 million hectare WA wheatbelt would not satisfy even half our mining sector's 167 million tonne carbon equivalent sequestration needs for the next 25 years.

The director of the Primary Industries Climate Challenges Centre said it was "an imperative" farmers inset any valid emissions reduction or sequestration achievements on their land to help their own farm's carbon balance sheet.

A specialist in carbon farming accounting, Professor Eckard said based on current trends for farm commodity sector pathways towards net-zero emissions, Australian farms would probably not sequester enough carbon to satisfy their own needs, let alone help other industries balance their books.

Addressing a major dairy conference in NSW, he said producers must focus on becoming attractive as least carbon-costly food and fibre commodity suppliers to local and global supply chains.

Rather than selling credits, farmers should start doing basic on-farm audits of their storage and abated methane successes to demonstrate their low emissions credentials when the likes of Coles, Cargill or Saputo came knocking.

"The more a farmer sells out of this finite stock, the less is available for their own net carbon balance in the future," he said.

"Once you've sold those credits, you can't grow them again on that land - it's a bit like selling off a paddock."

Supermarkets and the commodity giants buying the 70pc of agricultural products exported from Australia would prioritise doing business with the lowest emitting farmers so they could limit the credits they needed to buy to counter their supply chain emissions.

"We have to flip the language to stop talking about farmers providing offsets for Woodside Petroleum to cover its emissions, because you need to have something to show for yourself," he said.

Professor Eckard was addressing Dairy Australia's Raising the Roof conference in the Hunter Valley, attended by hundreds of big scale farmers and dairy industry service providers.

He said it was imperative dairy farmers take note of the emerging environment, including the corporate and consumer perceptions about what constitutes a carbon-friendly food production chain.

"You need to remain at the front of the queue when the supply chain companies are forced to decide what milk - or plant-based milk - to buy based on the emissions footprint that best fits with their stated targets," he said.

Conveniently, enterprises which operated good herd nutrition, pasture and soil management, manure management and herd management regimes, based on current best practices, also had low dairy farm emissions intensity.

Improving soil carbon and strategically planting trees also had co-benefits such as improving soil moisture holding capabilities and shade and wind protection for stock and pastures.

He believed technologies such as rumen methane management products, farm manure digester plants and nitrogen fertiliser coating inhibitors which reduced nitrous oxide emissions, could even cut the average dairy farmer's emissions in half, tomorrow.

However, they were expensive, and without clear price signals to reward producers these technologies were not yet cost effective in their own right.

"Beyond these technologies, however, by 2030 we expect other feed supplements, inhibitors, vaccines and early life programming strategies will deliver the next step in reducing farm emissions.