Red meat sector emissions down by 30%
Land use and productivity changes in the red meat sector mean absolute emissions have declined by 30% and emissions per unit of product by 40% since 1990, a Lincoln University researcher says.
Derrick Moot, who leads the dryland pastures research programme at the university, summarised the work of a number of scientists.
He acknowledges that the paper may be viewed as controversial, as agriculture is often blamed for climate challenges.
The paper showed New Zealand produced more than 70% of its energy from renewable sources, such as hydropower. With cleaner sources of energy, New Zealand’s greenhouse gas (GHG) emission profile was different to that of other developed countries.
This meant 48% of greenhouse gas emissions were from agricultural production, with methane emitted by grazing ruminants and nitrous oxide released from fertiliser application and urine patches, the paper said.
That meant agriculture took centre stage in political debates,
Moot said. But land use change and a drastic reduction in stock numbers were the first contributors to reduced emissions, he said.
In the 1990s, centre pivot irrigation was used in the Canterbury summer dry region for the first time. This led to an explosion of dairy farms. As dairying grew, extensive sheep and beef farms were sold, and these farmers reestablished themselves on hill country, Moot says.
‘‘The total number of sheep and beef farms declined from 19,600 to 9165. The red meat sector lost much of the flat and rolling hill country that had traditionally
been used to finish or grow lambs to slaughter weight. These finishing farm numbers declined from 6650 to 2085,’’ the paper said.
The number of breeding ewes were reduced from 40.4 million in 1990 to 16.6m in 2021.
The grazing land area used by sheep and beef also declined, from 12.4m hectares to 7.7m hectares. Land loss also meant total beef cattle numbers declined from 4.6m to 3.9m, the paper said.
The paper shows that feed efficiency meant the lambing percentage had increased from 100% to 132%, and lamb carcass weights at slaughter increased 32%, from 14.4kg to 19kg per animal.
This meant more animals were grown from less feed. This was a result of intensification, which played the next part in reducing the sector’s emissions.
‘‘The easiest way to stop a lamb from producing methane is to grow it as quickly as possible and get it to a killable weight. That’s what has been done through intensification,’’ Moot said.
Much of the intensification is the result of the use of legumes, which provide a good source of feed for sheep and beef. The better the source, the faster animals grow and the sooner they can be processed.
Legumes also leave nitrogen in the soils for other plants to use and reduce nitrogen leaching. Livestock that ate legumes also produced much less methane.
‘‘Part of that minimisation of impact had been to encourage sheep and beef farmers to use legumes in their system to increase feeding,’’ Moot said.
Higher lamb growth rates because of better feed shortened the lactation phase by 35 days and contributed to reduced methane emissions.
The red meat sector has also seen a 21% reduction in nitrate leaching per kilogram of saleable product over the years.
‘‘With the planting of land to exotic and native forestry at an individual farm level meaning the sector is close to or already carbon neutral,’’ the paper said.
From a global perspective you had a choice between intensification or deforestation. Unless other ways of producing food were discovered those were the only choices one had, Moot said.
‘‘There’s a rose-tinted view that we can reduce production and reduce our impact on the environment. It can be done with production of food that goes to a local farmers’ market, but it doesn’t work on a global basis,’’ he said.
Moot says media commentary on climate change was from a northern hemisphere perspective, where there were feedlots, soy imports, and cattle were grainfed.
‘‘That’s not what we do in New Zealand. We are not perfect but our meat industry has comparably internationally low greenhouse gas emissions,’’ Moot said. ‘‘Our job as agricultural scientists is to increase efficiency and minimise the negative impacts. The industry can use nitrogen but should not be addicted to it. We should use legumes that has a high feed value and also fixes nitrogen.