Mackay suggested having Sage as agriculture spokeswoman was like a "red rag to a bull" for many farmers, but Shaw disagreed.
"She actually understands the sector. She's Minister for Land Information and Conservation and has a lot to do with farmers."
Shaw said he had talked to farmer groups with Sage and was "extremely impressed" by the "respect that they hold her in."
A major part of the Green Party's agriculture policy was focused on helping the rural sector transition to climate-friendly practices, such as organic and regenerative farming.
There was a "huge amount of interest" in organic and regenerative farming, Shaw said.
"I get, anecdotally, these reports of meetings of groups of farmers who are investigating how to move towards more regenerative practices and so on, and they're all booked out - people really want to do it."
Shaw acknowledged that farmers may not have the funds to move to regenerative practices, which was why the Green Party was promising to spend 300 million to "offer practical support" to help them get there.
The Green Party also wanted to place a levy on nitrogen and phosphorous fertilisers and ban Palm Kernel Extract (PKE). Shaw said a number of farmers had "challenged" him on banning PKE, without also banning palm oil.
"We absolutely want to do that ... it is a horrendously destructive product," Shaw said.
PKE was a waste product of the "core product" palm oil, Shaw said. He believed that reducing the market for PKE would decrease the profitability of palm oil.
"Anything that we can do to bring an end to that practice overseas is a good thing for all of us."
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Meanwhile, a levy on phosphorous fertilisers was a "price at the margin", which Shaw had calculated would cost the average dairy farm "about $1500."
He hoped the levy would act as a deterrent.
"Of course the whole point here is for people not to pay it - i.e. to become just a bit more efficient with its use - there are people who are actually doing really well and wouldn't attract any levy at all."
"The point really is just to try and drive a bit more efficiency into people's decision-making."
The Green Party also wanted to ensure land use was diverse and sustainable, by changing rules around forestry, and strengthening land use rules to protect high quality soils and farmland.
"I think that we do need to make sure that our urban centers go up rather than out, and that we do actually make sure that those really high quality pieces of farmland stay in farmland, because one thing is for sure - with the growing population on the planet - we're going to need more food in the future rather than less," Shaw said.
Tune in to The Country on Thursday to hear from National Party's agriculture spokesman David Bennett, and Friday to hear from Labour's agriculture spokesman Damien O'Connor.
