It’s been a sad week for agriculture in Hawaii — and not only because Alexander & Baldwin Inc. announced that it’s closing Hawaii’s last sugar plantation, the company’s 36,000-acre farm on Maui.

The same day, longtime Hawaii island farmer Richard Ha told employees he’s shutting down his Hamakua Springs Country Farms, at least for the growing of crops that people eat.

Ha stopped growing his tomatoes last year and now will no longer produce his mainstay bananas after the current crop goes to market.

While A&B talked vaguely of transitioning its massive acreage to diversified farms, cattle, flowers, agroforestry and biofuel, Ha said he’s exploring an option where the future of Hawaii agriculture may truly lie: pakalolo.

He’s been approached to lease some of his 600 acres and hydroelectric — and lend his expertise on “growing things” — to one of the groups that has applied for a state license to grow and sell medical marijuana.

The marijuana deal “is not a sure thing,” he said in his announcement. “When they first came to talk to me, I didn’t take it very seriously. But in the last few weeks, it’s become pretty serious.”

Ha didn’t elaborate, but it’s not a move he would undertake lightly as a numbers-crunching businessman who has been a leading voice for greater economic opportunity to provide for future generations on Hawaii’s poorest major island.

Several well-heeled parties are competing for the state’s eight potentially lucrative medical marijuana dispensary licenses.

While Ha personally doesn’t favor retail marijuana sales for recreational use, others see medical marijuana as training wheels for eventual full pakalolo legalization.

Hawaii lawmakers attending a recent legislative conference in Colorado visited Vail’s Green Mile and took great interest in that state’s legalization of retail marijuana sales.

State marijuana programs are risky because it’s still a federal crime, but legalization here could be a bonanza for local farmers — and not only to supply the Hawaii market.

With Hawaii’s long growing season and the excellent reputation of the bud long cultivated here illegally, marijuana could become a significant export crop as more states and countries legalize pot.

Big marijuana would be in keeping with Hawaii’s agricultural history, which has been less about feeding local residents than export crops such as sugar, pineapple, macadamia nuts, coffee, and more recently, seed corn.

If marijuana is ever fully legalized, you have to wonder how much of A&B’s former Maui sugar lands will end up in its production.

It would no doubt be a boon to the local economy and tax base, but the potential social effects of widespread marijuana use aren’t fully understood, and pot farming does little to advance the state’s goal of food self-sufficiency.

When smart farmers like Richard Ha can’t make a go of it, that seems a pipe dream.

Reach David Shapiro at volcanicash@gmail.com or blog.volcanicash.net.