(NAFB) – Deere & Co. couldn’t reach an agreement with workers on a six-year labor contract, prompting thousands of employees to begin a strike on Thursday.

Members of the United Auto Workers overwhelmingly rejected a contract that was previously agreed on by the union’s leadership and the tractor maker. After weeks of negotiations, UAW leadership and the world’s biggest farm equipment maker reached agreements on wages and other benefits. However, Reuters says 90 percent of the union’s workers voted against the deal. The tentative deal had covered roughly 10,000 production and maintenance employees in 14 facilities scattered around the U.S.

“Pickets have been set up, and our members are organized and ready to hold out and fight for a contract they believe meets their needs,” says Ron McInroy, UAW Region 4 Director.

The company says it remains committed to reaching a new agreement, adding that it hasn’t figured out a timeline for finishing the negotiations. The rejected contract proposal would have given five percent wage hikes for some workers and a six percent boost to others. A source familiar with the negotiations says the workers understand they had to make concessions in the past and now want some of those back when Deere is doing financially well.

The strike is taking place in the middle of harvest, making it difficult for farmers to find parts for tractors and combines.