The grant came from Nga Pae o Maramatanga, ("Horizons of Insight"), one of the country's seven Centres of Research Excellence.
She has been based at the university's Centre for Sustainability: Agriculture, Food, Energy, Environment for the past eight years, and has also received a $200,000 grant from the same centre.
That was for earlier research which investigated applying Maori traditional medicines to farming.
Dr Johnson's work was entirely funded on "soft money" and gaining such contestable funds was "hugely competitive", she said.
About three years ago, her paid employment had been reduced to 20% of full-time because of funding difficulties, but she was now working full-time.
Dr Johnson is the new project's principal investigator and the latest funding will support an eight-strong interdisciplinary team.
The research project, titled "Indigenous Agroecology" (He Ahuwhenua Taketake), aimed to use findings from Maori and other traditional knowledge about plants, including medicinal plants, to promote more sustainable farming practices.
Native plants could be used not only to shelter farm animals and to keep them away from creek banks but also promoted biodiversity and could deliver significant animal health benefits, she said.
Fast-growing matipo could help animals counter parasites.
Researchers aimed to develop an economically viable farming model that would supply unique products with a low chemical signature, to meet a "growing global demand".
"We will be investigating how science can combine with traditional knowledge to achieve the goals of clean water, healthy land, healthy produce and a sustainable resilient farming system."
Dr Johnson comes from a farming background and has several tertiary degrees, including a PhD in zoology from the University of Otago.
