The Loudoun County Board of Supervisors voted Tuesday to adopt a nearly $1.8 billion budget that will slightly lower the property tax rate and boost spending on economic development.

The new tax rate of $1.235 for fiscal 2013 means a 5-cent decrease from the current rate of $1.285 per $100 of assessed value. As a result, a resident with a home assessed at $400,000, the county average, will see a property-tax reduction of $200.

The board also voted to adopt a capital improvements program, totaling about $1.43 billion, for county government and school projects through 2018.

Despite the hopes of some board members that the budget would pass unanimously, supervisors Eugene A. Delgaudio (R-Sterling) and Suzanne Volpe (R-Algonkian) remained opposed. The fiscal plan was still too costly for taxpayers, they said.

For Loudoun’s recently elected all-Republican board, the budget work sessions reflected campaign promises of fiscal responsibility and economic growth. The supervisors enhanced the county’s economic development department, adding three full-time employees and nearly $600,000 in funding, even as they trimmed more than $30 million from the fiscal plan initially proposed by County Administrator Tim Hemstreet. The cuts included $22 million from the budget requested by the county School Board.

To the dismay of some residents, a number of popular programs and organizations will not receive funding, including Loudoun’s Drug Court; the Loudoun Master Gardeners, a gardening education and volunteer program; and several nonprofit organizations.

The board began its budget review with even more ambitious cuts in mind. Early last month, members voted to start their discussion with a proposed tax rate of $1.21 per $100 of assessed value. Imposing that rate would have required about $50 million in cuts to the county budget, and the public school system would have faced a funding gap of $44 million, a challenge that county leaders soon deemed insurmountable.

The adopted plan leaves the Loudoun School Board to grapple with $22 million less than it initially said was needed. Still, the schools are to receive $825 million in county funds, an increase of $58 million over this year’s budget. Loudoun’s school system, the fastest-growing in the region, will open two new schools and absorb about 2,500 new students in the fall.

A handful of last-minute motions preceded the budget vote Tuesday. Board Chairman Scott K. York (R-At Large) made one last appeal to save the county’s urban horticulturist position, which oversees the Master Gardeners volunteer program. Funding the position, York said, would be “a wise investment” in the community.

“Through this program, over 2,000 pounds of fresh vegetables and fruits are donated to those that are in need in our community,” he said. “We have nearly 200 active volunteers that last year donated about 14,000 hours . . . estimated to be worth over $300,000. And they do a great job.”

Despite receiving support from Vice Chairman Janet Clarke (R-Blue Ridge) and supervisors Kenneth D. Reid (R-Leesburg) and Geary Higgins (R-Catoctin), York’s motion was narrowly defeated.

The board approved the reinstatement of the county’s energy manager position, which had been cut during a previous work session. Lewis Rauch, the county’s director of construction and waste management, told the board that the department would be unable to perform basic functions, such as utility rate negotiations, if the job were eliminated.

“We wouldn’t have a person looking out for those issues; we would pay the rates as the rates are mandated by the utility organizations,” Rauch said. “It is a position that does play a large role in our day-to-day operations.”

Before casting a final vote on the budget, several supervisors vowed that their efforts to cut costs and increase government efficiency would continue. Even Delgaudio, who voted against the budget, said he was pleased to see the tax rate drop.

“This board has done the best it can for now,” he said. “We have only just begun . . . in 12 years of voting on the budget, this is the first time when the rate of increase has actually slowed a bit.”

Supervisor Matt Letourneau (R-Dulles) said he thought the freshman members of the board, despite their relative inexperience, made the most of a difficult task.

“It’s really impossible to please everybody,” he said. “I am a little bit concerned that we underfunded the schools . . . but I am pleased that we at least went back up $22 million to get to a more reasonable sum.”

But Volpe, along with Delgaudio, said the board must demonstrate a greater effort to make “hard choices” to ease the burden on taxpayers.

“I believe the county will face more hardship if we continue to kick the proverbial can down the road,” she said. “I believe more hard work and more sacrifice is needed in order to truly secure a prosperous future for the county. . . . I cannot, in good conscience, vote for the proposed fiscal ’13 budget.”

In his closing comments, York compared Loudoun’s growth with that of neighboring Fairfax County. When Fairfax was at a comparable stage of development to present-day Loudoun, the property tax rate there was $1.70, York said.

“We have managed our budget well,” he said.