CARIBOU -Particles of dirt, rocks, and potato tops filled the air Saturday on Orman Blackstone’s potato farm overlooking the city as a crew of seven worked their way harvesting a field of potatoes.

It’s the annual potato harvest in Aroostook County, where 66,000 acres of potatoes will be harvested and stored for sale through the winter and spring months. Potato growers such as Blackstone, who has 250 acres devoted to spuds, employ hundreds of people during the harvest.

Blackstone and other growers in Caribou and in the St. John Valley say the quality of this year’s potato crop is good, but the total yield may be down as much as 10 percent because of the weather.

“It wasn’t a particularly good season because of the weather,” O.K. Blackstone, as he is known locally, said Saturday. “It rained a lot early in the growing season, and then it turned dry.

“We didn’t get the rain when we needed it,” the 70-year-old grower continued. “We didn’t get the rain when the potatoes needed the rain for bulking.”

Blackstone has been farming since he was 17. The Blackstones have been growing potatoes for three generations. Together, O.K. Blackstone and his two sons grow more than 1,300 acres of potatoes and rotation crops in the Caribou, Fort Fairfield and Presque Isle area.

One son, Murray Blackstone, and two grandsons, Don and Bill Blackstone, were named the Farm Family of the Year in 2003 by the Maine Potato Board, and another son, Kyle Blackstone, was named Young Farmer of the Year in 2002.

O.K. Blackstone estimated that his yield could be down as much as 10 percent, maybe more. He grows 150 acres of potatoes, and has another 150 acres of land devoted to grain. He and his son, Kyle Blackstone, grow processing potatoes, which need a longer season. Many of the fields are not yet ready to harvest.

O.K. Blackstone said he has 16 people on his payroll for the harvest, which began about a week ago. He said it would be a month before all his potato crop has been harvested.

Blackstone doesn’t believe it will be a great year for selling potatoes either. He’s looking for a break-even season because of a surplus of potatoes across the United States.

While Blackstone talked about potatoes, his large mechanical harvester plied the dusty field. Hauled by a large tractor, the machine had four people working at removing rocks and debris from the conveyors. The potatoes dropped into a large box truck that hauls 150 to 200 barrels of potatoes to a storage house a couple of miles away.

Also in the field were two winrowers, machines that dig potatoes and place them between two other rows, which are collected by the harvester. This allows the harvester to gather potatoes from six to 10 rows while working a field.

These days, Blackstone’s crew is working 13-hour days, from 6 a.m. to 7 p.m. Some years, some harvesters operate until 9 p.m. or later, working with lights.

Potato harvesting is noisy, dusty and hard work. Yet Blackstone’s crew seemed in good spirits, laughing and joking as the machine turned around at the end of the field.

In the St. John Valley, where more tablestock potatoes are grown, the harvest seemed further along. Several growers in the St. Agatha, Frenchville and Madawaska area are done harvesting.

St. Agatha potato farmer Luke Derosier Jr. finished his harvest Saturday night. He grows 220 acres of potatoes, all tablestock.

“It took us 11 days to get the crop in,” he said Sunday morning at the Uptown Variety Store coffee shop. “Like most growers, the quality is good, but the yield is down.

“I lost some low-lying areas because we had too much rain for a while,” he said. “Growers with processing potatoes, like russets, still have a long way to go.”