KINGSTON, R.I. — To feed Rhode Island’s population properly — based on USDA dietary guidelines — it takes close to 1.5 billion pounds of food a year, meaning the Ocean State is short about 3,700 acres of agricultural land, according to a Michigan State University professor of sustainable agriculture.

Michael W. Hamm, Ph.D., gave a presentation last week entitled “An Economic Development Framework for Sustainable Agriculture” at the University of Rhode Island Center for Biotechnology and Life Sciences. The nearly full lecture hall included farmers, academics, students and policymakers.

Hamm’s talk focused on how to produce healthy foods while both maintaining the environment and remaining economically viable. He said it takes 360 billion pounds of food a year to feed this country’s 300 million or so people a healthy diet.

“We under produce our healthy guidelines when it comes to produce,” Hamm said. “During the last fifty years we’ve developed production centers for our produce. Our agriculture was more diversified fifty years ago.”

Climate-change concerns, rising fuel costs and a growing demand for local food are encouraging the return of small farms. “People are developing a reborn appreciation for farmers,” Hamm said. “The profession is seeing some newfound respect.”

That’s a good thing, considering California will have a difficult time maintaining its current rate of produce production. The Golden State currently produces half of the country’s fruits and vegetables. These crops are irrigated largely with runoff from snowpacks in the Sierra Nevada mountains, which just last month showed below-normal levels and led to the lowest-ever preliminary allocation by the water system that serves cities and farms across this vast West Coast state.

In the past week, a series of winter storms dumped more than 2 feet of snow in those mountains, but California still is in the midst of a three-year drought.

“In twenty to thirty years from now, California will not be producing half of the produce we eat,” Hamm said. “Much of our produce is grown in concentrated areas that are threatened by development.”

In fact, much of our agricultural land is under development pressure. According to Hamm, 63 percent of our dairy farmland and 86 percent of our produce farmland could be lost because of economic pressures.

Much of the rest of the country’s fruits and vegetables not grown in California are imported. But with 48 countries and counting that are faced with stressed or scarce water resources, plus the prominent role the rising cost of energy plays in food production, Hamm said it is time to improve the social, environmental and economic viability of family farms.

“Ten years ago ‘local’ was a dirty word,” he said. “We’re now beginning to understand its importance.”

Family farms across the country are disappearing, with low profitability, developmental pressures and market failures not only displacing the current generation of farmers but also markedly discouraging the next generation, according to Hamm. That trend, he said, needs to be reversed, because to obtain a nutritionally adequate diet through a sustainable food system that maximizes community self-reliance requires local farms and an influx of new farmers.

According to the 2007 farm census, Rhode Island has 2,418 acres for vegetable production, 580 acres of orchards and 542 acres that grow potatoes. Those 3,540 combined agricultural acres are nearly 4,000 less than what is needed to feed Rhode Islanders a balanced diet that recommends five servings of fruits and vegetables a day.

“Our farming population is getting older,”  said Hamm, noting that the average age of a Rhode Island farmer is 56. “We need to help those who want to be the farmers of the future.”

The next generation of Rhode Island farmers, however, face a substantial hurdle: Ocean State farmland is the most expensive in the country.

This new generation of farmers — a group that still needs to be developed and nurtured locally and nationally — will need training, business development skills, capital, markets, continuing education and, of course, land.

“There is a direct link between public health and economic development opportunities,” Hamm said. “We need more family farms.”