Voters in Ayer and Shirley approved one stage of a plan to spend $7.1 million to improve athletic fields in the Ayer Shirley Regional School District on Saturday.

Ayer voters favored a referendum to allow the district to incur debt, by 425 to 238. Shirley voters opposed the idea, 350 to 394. That left the combined vote as 775 in favor, 632 against. Turnout was 9 percent in Ayer, 17 percent in Shirley.

At Special Town Meetings in each town set for later this month, voters will be asked to authorize Proposition 2 1/2 debt exclusions to cover shares of project costs. Ayer will pay 60 percent of the co st, and Shirley 40 percent, per the Regional Agreement.

Voters also will be asked to approve debt exclusions for their towns in yet-to-be-scheduled separate referenda. Those votes were originally scheduled to be taken on Saturday. However, Shirley selectmen did not vote to call the referendum within the state's 35-day window, meaning a vote held Saturday would not be valid. Shirley selectmen canceled that referendum on Monday, and Ayer selectmen followed suit the next day.

Proponents say the fields proposal, in the planning stages for 18 months, is necessary to bring those facilities up to date. They also say newer fields will be safer.

Opponents say the plan is too expensive, and that the injury argument is based on "anecdotal evidence."

The School Committee has pledged not to incur the debt unless the debt-exclusion question passes in both towns.