MIDDLETOWN — Voters will be asked in November to approve a $2-million bond to support open-space preservation, a referendum that residents overwhelmingly supported in the last general election two years ago.

The Town Council on Monday night agreed to place the issue on the fall’s ballot after hearing from a number of preservation supporters, some of whom came to Town Hall with cow-shaped cutouts reading “Vote Yes on Open Space Bond.”

“Middletown voters should be given the right to decide on a $2-million bond,” said Edward S. Clement Jr., executive director of the Aquidneck Land Trust. “Now is the time to act for land conservation in our community. Many developers continue to target Aquidneck Island because of the beauty and quality of life here. The word is out that this is a lovely place and it’s attracted developers from across the country.”

“We need to give our voters credit for their intelligence, their wisdom and their vision and allow them to determine whether or not this is in their best interests,” said Mason Hawes, chairman of the town’s open space and fields committee.

The November referendum, if approved, would simply give the Town Council permission to issue the bonds. The bonds, which would be repaid over 20 years, would not be issued until the town is ready to spend the money.

“The bonds would only be used when we had something to buy,” Town Administrator Shawn J. Brown said yesterday. “This would give the council the ability to borrow money if a property came along.”

Once issued, the town’s average annual debt service would be $147,250, a cost that would add about 6 cents to the tax rate.

The town has forwarded the enabling legislation to Middletown’s State House delegation. The General Assembly’s 2008 session is expected to end this week.

In related news, the town, the Aquidneck Land Trust and the Kempenaar family, signed a purchase-and-sale agreement last Friday to conserve the Boulevard Nurseries property on East Main Road, permanently protecting 31 of the acres from development. A prominent real-estate developer had sought to build 35 new homes on the site, officials said.

Under the agreement, the Land Trust will pay the Kempenaars $500,000 for a perpetual conservation easement on their property. A conservation easement is a legal agreement by which a landowner transfers part of a property’s interest to a conservation organization to permanently restrict that property’s uses.

Then, the town will buy the land for $1.5 million with open-space money. The Kempenaars will retain about three acres around the garden center and another two acres surrounding outbuildings on the parcel’s southern boundary.

The Land Trust said the scenic property, on busy East Main Road, is important because it abuts the already-conserved Tibbetts and Albro Woods properties. Combined, the properties form 72 connected acres that may one day be used as a recreation complex, officials said.

Housing development at Boulevard Nurseries would have burdened town services and added 300 vehicle trips to the clog of traffic using East Main Road, according to the Land Trust.

“Future generations will benefit from the preservation of the property for farming, watershed and wildlife protections and recreational opportunities,” Brown said in a news release announcing the preservation. “The Kempenaar family has again showed their commitment to the community by giving us this opportunity.”

“Our family has a long-standing and deep connection with this property, agriculture, Middletown and Aquidneck Island, for that matter,” John Kempenaar said in the release. “There were other interested parties such as various developers, but we are so pleased that the land trust helped us pull it all together in a creative way that we felt was right and that the town had the vision to support the plan.”

mwims@projo.com