Divided county supervisors have carved an exception in their land-use laws for a North County development — a move that could allow more houses to be built on agricultural land there.

It also opens the door to other developers to ask for the same preferential treatment, some supervisors said.

The decision, made at the Board of Supervisors meeting Tuesday, favored Estrella River Vineyard LLC, which wants to build an agricultural cluster subdivision on 562 acres north of the Paso Robles city limits.

In these clusters, most of the land is set aside for agriculture, and houses go on the rest.

But the number of houses depends on land-use factors, including soil type.

For at least 25 years, the county has been using standardized maps of the county prepared by the federal Natural Resources Conservation Service to determine soil type, according to Mike Isensee, a county agricultural resources specialist.

Estrella’s attorney, Jamie Kirk, argued that developers should be able to make their own determinations. She said there are six soil specialists in the county who can do the work.

Kirk said 95 percent of the Estrella site is protected for agriculture. Even if a more liberal interpretation of what kind of soil sits there prevails, it will mean a 20-acre minimum lot size rather than a 40-acre minimum, Kirk said.

Supervisor Harry Ovitt strongly supported Estrella.

“Maps are guidelines,” he said. “They’re not absolute.”

The decision followed a highly abstruse, three-hour discussion that, at times, involved disagreements over soil types, “K-factors” and the importance of where a comma should be placed in a sentence.

The argument played out against the backdrop of a county Board of Supervisors that frequently says one of its primary missions is to preserve agricultural land.

In the end, supervisors gave Estrella the exception to standard land-use policy that the developer requested. The vote was 3-2 with Ovitt, Jerry Lenthall and Katcho Achadjian favoring the move and Bruce Gibson and Jim Patterson opposing.

The three-member majority had sought at a December meeting to help out Estrella, which wants to move forward with its plan but can’t under the rules using the NRCS maps.

“Is there something that can be done for this project?” Achadjian asked at the time, and Lenthall argued that Estrella was facing exigent circumstances.

Lenthall suggested that the planning staff ask the NRCS to make an exception in Estrella’s case.

In January, the staff did, but the NRCS would not go along, Planner Bill Robeson said Tuesday.

When supervisors voted to make the change, they went against the advice of the county Planning Commission, planning staff and Agriculture Department.

Gibson said allowing developers to pick soils scientists would have a profound effect on growth. Patterson agreed, arguing that soil can be manipulated to get the classification that a developer wants.

Supervisors told their staff to continue processing the Estrella application and keep working on a change in their land-use laws that could open the door to regular use of developer-picked soil scientists.

They also left open the door to contracting their own scientist, with the developer footing the bill.

The Estrella soil review, even if it is done by the developer, will receive a county peer review, according to Supervising Planner John Nall.

“I’m comfortable there will be checks and balances,” Lenthall said. “We’ll have more than one bite of the apple.”