AgResearch has released results of work that provides scenarios where farms can reduce greenhouse gas emissions and nitrogen losses to waterways.
The work is at least the fourth major research project in the past 10 years indicating reductions are possible.
It presents outcomes similar to three earlier pieces of research, including a 2009 DairyNZ sponsored Waikato nutrient efficiency study.
That report, like the rest, required stocking rates to drop by at least 5%, nitrogen use to decline significantly and greater use of bought-in feed in some cases.
AgFirst director James Allen and ecologist Dr Alison Dewes were both involved in the 2009 study.
Dewes has since modelled multiple scenarios where farms reduce gas and nitrogen emissions and helped farmers put them into action with positive profit results.
While the AgResearch work is valid, a decade down the track there should have been more progress made on farms to have changes in place.
“We did that Waikato study a decade ago and no action was taken from it.
“It showed it was possible to drop stocking rates and make major reductions in nitrogen losses while also improving profit, yet that report disappeared.”
Dewes is now working with Pamu applying some of her own modelling that aligns closely with the AgResearch findings.
That includes lowering stocking rates on lighthouse farms owned by the state-owned enterprise in sensitive catchments or where more intensive winter grazing is practised.
Allen said the AgResearch outcome relies heavily on farmers getting a value-add premium of 26% for producing in a carbon-neutral manner.
“You would have to ask though to show me the money. If farmers can really get a 26% premium I think you will find they will be stepping up. But getting those premiums is not always that easy.”
He is also concerned lowering stocking rates, a common to all the research, will affect farm management.
“This particular study is reducing cows from 2.9 a hectare to 2.4. If you now have half a cow a hectare less how do we maintain pasture quality through spring as effectively?
“It is an old adage that it’s easier to run a farm that is overstocked than when it is understocked.”
Lowering grass input and feeding more maize is also part of the latest research’s solution to nitrogen and gas losses.
But that requires considerable infrastructure to do efficiently and cost-effectively, such as feed pads and more machinery.
“And maize will only work for a certain proportion of NZ as a crop.”
Allen said DairyNZ must give farmers some clear direction now nutrient and gas goals are in place.
“If the answers do lie in fewer cows and more maize then farmers will want to see where this is working and how they can apply it on their farm.”
He appreciates DairyNZ faces a challenge with such a broad church of levy paying farmers. Some operate at high input levels with others at the other extreme on low-cost, all-grass systems. That will make it hard for an industry body to promote uniform change.
DairyNZ strategy and investment leader Bruce Thorrold said some of the assumptions made in AgResearch’s latest work are heroic.
They include offsetting non-reducible carbon emissions by buying credits and exporting farm nitrogen losses to another farm growing maize.
“You need to think about the boundary of a farm system. This study goes beyond the farm boundary.
“There is also an assumption on a low-carbon premium but there is a lot of uncertainty around premiums and without the premiums the farms had a drop in profitability across every scenario in the research.”
Thorrold said on the upside the research has again helped highlight the need for greater feed efficiency.
“Now we have targets to aim for we will be doing more with farmers on how to bring those three critical things of increased profit, lower nitrogen losses and lower greenhouse gas losses together through greater efficiencies.
“It is a challenging target to move 12,000 farmers in the time available.”