Red meat sector emissions down
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, one 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 says.
But land use change and a drastic reduction in stock numbers were the first contributors to reduced emissions, says Moot.
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 16.6 million in 2021. The grazing land area used by sheep and beef also declined, from 12.4 million hectares to 7.7 million hectares. Land loss also meant total beef cattle numbers declined from 4.6 million to 3.9 million, the paper says.
The fewer animals there are, the smaller the emissions. 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’s been done through intensification,’’ Moot says.
Much of the intensification that Moot hails as success is the result of the use of legumes.
They 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. They also reduce nitrogen leaching this way.
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. The use of legumes also minimises some requirements for nitrogen fertiliser,’’ Moot says.
Because nitrogen fertiliser is a petrochemical-based product its price increases as the cost of energy goes up. This in turn leads to higher food prices, 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.
Moot says intensification does however have a negative side. ‘‘Historically when we increased the world population we increased the land used to feed the world and we cut down forests to do so. In the 1960s agriculture was intensified by the use of nitrogen fertiliser and we could stop cutting down forests for the most part. We now feed almost 8 billion people on the same land area from which we used to feed three billion people.’’
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. Europe has done this by abdicating responsibility for much of its food production to South America.’’