Roland Darcey tried sweet potatoes on his Upper Marlboro farm this year, but he doesn't think he'll plant those again. Too much effort for too little profit, he said.

Instead, Darcey, 57, said he'll probably stick to tobacco and corn, two crops that have worked for four generations of farming Darceys in Prince George's County.

But Darcey is looking further ahead than next planting season.

Prince George's is a county where land used for farming has decreased steadily since the late 1950s. And, more and more, farmers there have become concerned that urbanization could affect the quality of life for people who make their living off the land.

As a result, Darcey -- who is chairman of the County Council's Task Force on Agriculture when he is not occupied with his 155-acre farm -- asked the county to adopt a "right-to-farm" law that would protect farmers from complaints from nearby homeowners that their farms are a nuisance.

On Tuesday, the County Council unanimously approved the measure.

The bill is not an antidevelopment measure, Darcey stressed, merely one of several shields suggested in his task force's April 1983 report to help protect county farmers.

"There have been nuisance complaints which have put people out of business," he said.

Those complaints, Darcey said, often come when developers build subdivisions near farms, which by their nature are a source of noise and unpleasant smells.

"Those people are thrilled to be out in the country with all the green and all the scenery, but when the farmer puts his manure on, they have to close their windows because of the unpleasant smell," Darcey said.

The new measure is a stricter version of an existing state law, and stipulates that as long as a farm does not change its type of operation, it is protected from complaints brought by neighbors.

Thomas D. Tyson, a planner with the Maryland-National Capital Park and Planning Commission, said that he is unaware of any lawsuits that have grown out of such complaints about farms.

Darcey, who worked with hired hands in his fields every day last week digging sweet potatoes and loading them into baskets for roadside stands, said that the new law is not meant to give farmers a license to be negligent.

Instead, he said, it will protect farmers from such drastic action as having to move -- as he had to when subdivisions were built near a hog farm he was operating in Camp Springs.

With the new law, Darcey said, prospective residents of a farm area will know in advance what they are getting into.

Farmers already get a certain measure of special treatment in the area of assessments. Property tax assessments on agricultural land, which are set by the state, are much lower than those placed on other types of property.

"I pay more tax on my house on that hill than I do on my farm," Darcey said, motioning to the white farmhouse overlooking his field and nearby Ritchie-Marlboro Road.

"If it wasn't for that law, we wouldn't be able to farm at all," he said. Most farmers are aware, he said, that they can get a whole lot more from their land by selling it to a developer than by farming it.

But thus far the county has not used all of the tools at its disposal to protect its 23,000 acres of cropland, which the county extension service says produced nearly $17 million in marketable products in 1982.

The Prince George's council also gave its approval yesterday to a proposed General Assembly bill that would strengthen the state's agricultural practices law. The legislation would strengthen the existing state right-to-farm law, a move council staff members said would provide a stronger legal basis for the new county law, which now goes to County Executive Parris Glendening for his signature.

Specifically, it would exempt agricultural operations from nuisance complaints if they are operating within "generally accepted agricultual practices," as defined by local zoning ordinances and state law.

The state of Maryland also gives local jurisdictions the option of creating agricultural districts that limit land acquisition and construction of large capital facilities in designated areas and give developers incentive to build elsewhere.

Agricultural districts, as defined by the state, allow only one dwelling place to be built for every 25 acres, which discourages extensive development.

Montgomery County adopted such a farm preservation program in 1981. Under that plan, county extension agent Douglas Tregoning said, farmer owners whose property is located in the special agricultural districts receive compensation for what they would otherwise be able to gain by selling their land for development.

Farmers in these districts in turn can sell their "total development rights," as they are called, to developers who can then build in other areas of the county.

Prince George's has none of these districts, although the task force also recommended their use in its 1983 report.

But Darcey is optimistic that further protections are in store for farmers even as the county government continues to encourage residential and commercial development.

"Farmers have a lot of friends," he said. "Every voter has a friend who has been on a farm."