Guy McCaw keeps an eye out for rocks as the combine’s 35-foot-long header skims inches above the ground.

Behind him, small white chickpeas pour into the storage bin.

It’s a crop that McCaw and his partners — dad Jack, son Jesse and nephew John — started growing as a rotation with dryland wheat about three years ago on the land they farm in the Touchet Valley, about 60 miles east of Kennewick.

The plants look like withered tree skeletons standing about 18 inches tall. Fuzzy pods hang from the branches, each holding one or two chickpeas.

Each plant has between 18 to 30 pods, McCaw said.

Washington is the nation’s top grower of the beans. The state’s chickpea production has boomed since 2000, with total acres growing from 10,000 to 80,000.

Washington farmers produced about 39,800 metric tons of chickpeas in 2011, about 48 percent of all the chickpeas produced in the U.S. that year, according to the USA Dry Pea & Lentil Council. Idaho represented about 35 percent of chickpea production.

Washington’s chickpea crop was valued at about $17.3 million in 2010, according to the council.

Just one year of growing chickpeas on her farm near Waitsburg sold Cathleen Williams of Kennewick on the crop. Along with the price, yield was good, with the average yield in Columbia County about 1,100 pounds per acre, she said.

She plans to plant chickpeas again this year.

For farmers, the reason to try the legume in the place of dried peas as a rotation crop was simple.

“It’s a high value cash crop,” McCaw said.

The price is hovering around 40 cents a pound, and McCaw said they can get from 1,000 to 2,000 pounds of chickpeas, also called garbanzos, per acre.

Dried peas are closer to 15 to 16 cents, he said.

On a “garb” harvest day last year, McCaw steered the combine through the field at about 5 mph.

Behind the combine, the ground is bare, with only the roots of the chickpea plants remaining in the ground. Fine dust billowed behind, clinging to clothes and skin.

A few of the cracked pods made it into the combine’s storage bin. Those were still slightly green, McCaw explained. And they will be cleaned out at Blue Mountain Seed in Walla Walla, where McCaw’s chickpeas will go before being sold as feed and seed.

Some harvest garbanzos for the fresh market, but McCaw said they spray the plants to dry them out and harvest for the dried market.

About 120 days earlier, the McCaws planted the seed for their chickpeas using a drill pulled by a tractor, with about 2 to 21⁄2 seeds every foot.

Of the more than 10,000 acres his family farms, McCaw estimated about 20 percent this year were covered with chickpea plants, which put nitrogen back into the soil.

For the McCaws, chickpeas come at the end of almost two months of harvesting for them and 10 employees, with 16-hour days that start early with maintenance on the farm’s four combines.