Sonoma County government’s largest labor union has upheld its close vote approving a tentative contract, a step that likely marks the end of a tense tug-of-war with the county that began almost a year ago.

Sonoma County government’s largest labor union voted Tuesday by a slim 52 percent majority to approve a proposed labor contract that would balance a short-term salary freeze with future-year wage growth.

The largest group of unionized Sonoma County government employees plans to strike next month to protest what it says is county inaction on a union proposal to save taxpayer money and several other issues it says amount to unfair labor practices.