The district's 4500 square kilometres has 18 per cent of New Zealand's Class 1 land, and 14 per cent of its Class 2 land; the two best types.
"It's a highly productive region for New Zealand Inc."
The biggest challenge to making the most of that land was water.
In the hill country of northern Rangitikei getting adequate stock water has been the biggest challenge. In the coastal sand country to the south there have been major conversions to dairy farming, especially in the last two years.
"A couple of those would be using more water on a daily basis than Feilding. There's one that's using almost as much as Palmerston North city."
Contractors from The Catalyst Group are "the rubber on the road" for stage one of the water study. Staff include Greg Carlyon and Alistair Beveridge, both former Horizons Regional Council officers. They are charged with collating information, holding meetings and talking to farmers. Stage one of the study has three parts, Mr Watson said.
The first is to find out exactly how much water is available, in rivers and streams and in underground aquifers. Knowledge about surface water is already well advanced.
"We owe Horizons a huge vote of thanks. They have a very sound knowledge of surface water developed into their One Plan."
More work is needed on the groundwater resource. But initial studies say there are vast seams of water available, as deep as 600m underground.
The next element is to research how land use could change with irrigation, and how much extra money that could bring into the district. In the south there could be new crops, subdivision into smaller farms and intensification, with reliable stock water in the north.
Possible environmental effects will be considered. Mr Watson said two of the worst, salt incursion and groundwater contamination, seemed unlikely.
The final piece for stage one is case studies about irrigated land and talking to farmers about barriers to irrigation.
Two workshops were held in late March, one at Santoft and the other at Hunterville. Both had attracted plenty of people either sharing their experiences or keen to learn about irrigation possibilities.
A factors that emerged at the Santoft meeting was a need for more power infrastructure. It takes lots of energy to suck water up from deep underground.
"This isn't cheap. Some of these people will be paying for their farms a second time," Mr Watson said.
At Hunterville a few people were interested in irrigation, but most wanted reliable water for stock.
"Last year's drought impacted very, very heavily on the district. There are some real challenges. The Hunterville rural water scheme is maxed out and expensive to operate in terms of power."
Stage two will be funded by water users and government, not Rangitikei ratepayers. It's about planning and design, and a way to fund any future work.
Water could come from bores in individual or group ownership, from dams or from water diverted from the Turakina or Rangitikei rivers and stored for later use.
Mr Watson said there was enough interest to proceed to stage two, provided MPI agreed.
The final stage would be to build whatever was needed, and some government money could also be available for that.