PRESQUE ISLE, Maine — In the search for a third rotation crop for potatoes, trials at the Aroostook Research Farm in Presque Isle are showing some promise for field peas, a crop that once had a successful run in the region until the 1970s.

Jake Dyer, an organic grain farmer from Benedicta, has been researching alternative crops with the Maine Potato Board as potato growers are looking to improve their soil and find a third viable crop to add to potatoes and grains in their field rotation cycle.

In a project that the Maine Potato Board funded, Dyer led a trial last summer, growing plots of chickpeas, lentils and field peas — crops grown in other northern climates.

“I thought it could be a good fit for potato-grain cropping systems,” Dyer said of the group of crops known as pulses, plants in the legume family harvested for their dry seed, such as peas, beans, clover and lupine, during a presentation at the recent Maine Potato Conference in Caribou.

“It can be grown and produced using existing equipment. Worst case scenario, it is a beneficial cover crop,” he said.

The pulses are gaining in popularity, Dyer said. They’re gluten-free, high in fiber and protein, and they are used as ingredients in processed and fresh foods, and for livestock and aquaculture feed.

The trial last summer included chickpeas and lentils, two pulses that are high in value but also harder to grow, even in the drier climates of Montana, North Dakota, Manitoba and Saskatchewan.

Dyer said he wanted to try growing them, to test them out, along with field peas, which he and the University of Maine Cooperative Extension have been growing in trials for several years.

While the pulses require little or no fertilizer and can help capture nutrients in the soil, chickpeas and lentils are susceptible to the Ascochyta fungal blight and mold.

Growers in major chickpea and lentil regions rely on “an aggressive fungicide program,” which can eat into the overall income from the crop, Dyer said.

Chickpeas and lentils also are indeterminate plants, continuously and simultaneously growing foliage and flowers into the fall, creating a problem for harvesting them with an even ripeness. Growers had to harvest the chickpeas by hand, while they can harvest lentils with a combine, Dyer said.

In terms of quantity, the yields were comparable to other growing regions, although the chickpeas and lentils would have been unmarketable because of the mold they suffered, Dyer said.

“There is not a lot of efficacy of the fungicides that are labelled for lentils with white mold. And even once you find it, it’s too late anyway,” he said.

“Chickpeas and lentils are probably not the best choice for this area,” Dyer said, but there has been “a fair amount of success” with field peas in three years of trials at the Aroostook Research Farm.

Field peas “are an easier animal to tame,” he said. They’re determinate plants, developing faster than chickpeas and lentils while ending flowering after a mid-summer period.

“The flowering stops and the crop matures nice and even,” Dyer said. “They’re semi-leafless, with tendrils and grab onto each other and support each other. The lack of foliage allows air to blow through the canopy, so we didn’t have any white mold issues.”

In rough comparison to oats, the most common two-year rotation crop with potatoes and usually sold for animal feed, the pulses would have higher input costs. The grower needs to inoculate the seeds with a beneficial bacteria for the plants to fix nitrogen in the soil. But they also could have a higher return, Dyer said. Farmers can sell peas to food processors or use them as livestock feed. Conventional and organic dairy and meat farmers are increasingly seeking non-genetically modified sources of livestock feed.

From the late 1940s to the early 1970s, many potato farmers in the region grew field peas as part of a three-year rotation and sold them to the Birds Eye processing factory in Caribou. The plant closed in 1971, and the loss of a buyer for peas left farmers without a good reason to plant them or have three-year rotations.

Dyer said he’s talked with a company in Prince Edward Island, W.A. Grain and Pulse Solutions, that is looking to source green and yellow peas, fava beans, lentils and lupines from Atlantic Canada. Farmers in Prince Edward Island, Canada’s top potato producing province, also are in need of a third rotation crop.

The company is expecting to contract for more than 1,500 acres of production this year and would like to reach 5,000 acres in the Maritimes, Dyer said. He thought there might be some potential there for Maine growers.

Going forward, he said he’s going to continue trials with peas and try growing some other pulse crops.

“I’d like to investigate pulses that tolerate our type of climate like the favas and dry beans,” he said.