Friday, March 29, 2024

Our farmed meat is a green food

Neal Wallace
Exporters are not shy in promoting New Zealand red meat as grass-fed and free-range but recent studies by Oxford and Otago Universities have lumped our system in with feedlots to claim the industry is environmentally degrading and unsustainable. Neal Wallace investigates the true environmental impact of grass-fed beef.
Reading Time: 3 minutes

Work to differentiate the environmental footprint of New Zealand’s pasture-based red meat sector from feedlot systems that have a far greater impact has begun.

Beef + Lamb NZ chief insight officer Jeremy Baker said NZ grass-fed, free-range beef has been included in international studies that claim beef production is a major contributor to climate change.

In reality NZ livestock emissions have been falling and the environmental footprint is smaller than beef finished on feedlots.

The launch of B+LNZ’s Taste Pure Nature brand and associated environmental strategy are designed to differentiate grass-fed, free-range beef free of genetic modification and hormones.

Consumer research shows beef that meets that criteria not only attracts new consumers but can earn price premiums of 20%.

“That really is worth going for,” he said.

But the message has to get out and several recent international studies lumped pasture-based and feedlot systems together to conclude beef farming is damaging the climate and is unsustainable.

But research by scientists in the Netherlands and more recent work by AgResearch countered that claim, finding free-range systems use much less water than feedlots.

International researchers have determined feedlot beef production and processing uses 680 litres of water a kilogram of meat but AgResearch found NZ’s free-range beef system uses 45 litres a kilogram of beef and sheep meat 20 litres a kilogram.

Processing adds another 20 to 70 litres a kilogram to beef and lamb, still well below that used on feedlot systems.

Baker said the news for free-range farming gets better, with greenhouse gas emissions falling 30% since 1990 while production has been maintained and the value has increased 63%.

Emissions from beef alone have fallen 10% over that period.

“There has been a huge change in productivity of the sector and the profitability of the average farm is better than it was in 1990 – a great story of the sector doing more with less.”

Our farming system has a positive story to tell but that doesn’t preclude the need to address water issues such as nitrogen leaching, runoff and emissions of carbon dioxide and nitrous oxide, Baker said.

Reducing or eliminating nitrous oxide is challenging because it is a long-lived gas but reducing and stabilising the short-lived methane gas is more achievable. 

Science has determined that to restrict global warming to under 2C, methane emissions need to be stabilised at less than 1990 levels.

B+LNZ is seeking Government acknowledgement of the carbon-sequestering role of the 1.4 million hectares of native forest on the country’s sheep and beef farms.

“That is a very significant carbon sink,” Baker said.

Native bush absorbs carbon for 300 years but is not counted as a greenhouse gas carbon sink because most stands predate the 1990 baseline on which international climate change agreements start while the Emissions Trading Scheme is based on areas of plantation forestry.

The Paris Agreement on climate change offers hope the carbon-sequestering values of native bush can be counted.

“The Paris Agreement is broader with domestic policy enabling the Government to work out how to meet our obligations with a bit more flexibility than the Kyoto Protocol, which was tighter and more prescriptive.”

Getting credit for the carbon-holding ability of soil and pasture is more difficult because of the absence of internationally accepted science.

There is potentially four times as much carbon stored in soil than in trees but scientists have been unable to determine how it is fixed or how management affects the amount stored, he said.

Carbon is stored at plant root level and there is general agreement drought causes it to be released.

AgResearch principal scientist Stewart Ledgard said researchers around the world are investigating the sequestering value of soil and pasture and some research shows carbon is stored but then the science becomes complicated.

During photosynthesis plants, algae and some micro-organisms use sunlight to convert carbon dioxide and water into sugars incorporated into their cells – some of which are eaten by animals.

Decomposing animal material, plant matter, fungi, worms, bacteria and other microorganisms all contribute carbon to the soil. 

Most of this organic material degrades quickly with microbes feeding on it and releasing carbon dioxide back into the atmosphere through respiration.

However, a small proportion of it becomes tightly bound to the mineral surfaces of soil particles or encapsulated in clumps of soil particles.

In that state the carbon in soil organic matter is physically protected and less accessible to microbes. They are stabilised and can remain locked away for tens to hundreds of years.

Ledgard said research shows carbon accumulation occurs over many years when land use changes, such as from crop to pasture or trees to pasture.

“Once you have got stable pasture, plants and roots die and bugs in the soil use that and discharge carbon back in to the atmosphere.”

There is a chain of thought carbon accumulation stops after several decades but Ledgard said French scientists are researching further into carbon accumulation.

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