"I was surprised."
The judges said Birkett was a recognised leader in sustainable farming practices, who focused on boosting soil quality and was always happy to share what he knew with other farmers.
"I think it's probably a combination of things," Birkett said.
"We try to farm in a slightly different way than the mainstream, and probably in a more sustainable and environmentally-friendly way."
Birkett said on-farm costs and weather events had made it tough going for growers, but the awards were a morale booster.
"The arable industry's had some tough times recently and we're still probably struggling from a financial point of view, and I think it's really good to, sort of, push the morale of the industry up, and also get the recognition of the industry out there into the public as well.
"I think there's been multiple benefits of these awards."
Other winners on the night included Southland's Auld Farm Distillery, which took out the Innovation title for a single malt whisky made from purple wheat, black oats and black barley.
The Aulds also make a range of three gins from a base alcohol of oat, wheat, and barley.
The immediate past national vice-president of Federated Farmers Karen Williams, and her husband Mick, won the Environment and Sustainability Award.
Angela Clifford, an advocate for the arable industry who promotes food grown and produced in New Zealand, was named the 2022 Food Champion.
- RNZ