More than 10,000 farm environmental reports have been emailed and posted out this month, this year containing GHG assessments for the first time.
Methane and nitrous oxide emissions average around 10,000kg of CO2 equivalent a hectare and range between eight and 12kg for each kilogram of milksolids produced, according to the generalised information published by Fonterra.
But it is not planning to publish nationally or regionally aggregated figures because of the considerable differences between farms.
Some 80% of the standard GHG emissions are methane and most of that is enteric, produced in the rumen by methanogenic microbes in digestion.
Fonterra’s director of on-farm excellence Charlotte Rutherford says when farm owners know their numbers they can look at ways of improving their GHG efficiency.
The He Waka Eke Noa partnership between the Government, industry and Maori aims to equip farmers and growers with the knowledge, tools and support they need to reduce emissions and adapt to a changing climate.
Rutherford says annual emission reports for each farm are a big first step.
Reducing the GHG emissions footprint of milk production requires effort to maximise the percentage of farm dry matter utilised for milk production while also minimising other farm inputs.
New Zealand milk was already among the most sustainably produced in the world.
But with increasing concern from consumers, Fonterra and its farmers needed to position themselves for the challenges in the regulatory and market future.
Big dairy customers were setting themselves bold targets – Nestle for net zero emissions by 2050 and Starbucks to reduce carbon emissions 50% by 2030.
Wairarapa dairy farmer Aidan Bichan agreed that the carbon footprint requirements of major customers were a motivator for Fonterra farmers to monitor and plan for reduced emissions.
A climate change ambassador for the dairy industry, Bichan had used the N assessments over the past few years to change the timing and rate of application of N fertilisers.
Total N use has come down from over 200kg/ha annually to under 100.
“That has significantly reduced our nitrous oxide emissions by one third but we haven’t lost much milk production because we are now more efficient with our N use,” he said.
Cropping has changed from conventional cultivation to direct drilling, reducing the ground passes from five or six to two.
He thought methane reduction would be harder to achieve because the main drivers are cow numbers and feeding levels.
Some 300 winter milkers already got one-third of their diet from kale and a lower herd replacement rate would give some win-win benefits.
“First you have got to know your numbers, then make a plan and execute,” he said.
“What is good for the environment is also going to be good for our GHG emissions.”
Bichan is an equity manager with five other partners in the 900-cow Kaiwaiwai Dairies near Featherston, which was the 2020 regional supreme winner in the Greater Wellington Ballance Farm Environment Awards.
