Maryland's new secretary of natural resources says a federal program to reduce grain surpluses could be "one of the best things that's happened to the Chesapeake Bay in a long time."

Dr. Torrey Brown said the state is trying to use the PIK (Payment in Kind) program, under which farmers receive surplus U.S. grain in return for taking some land out of production, to help clear the murky waters of bay tributaries.

The Department of Natural Resources, working with other state and local agencies, is asking farmers to set aside PIK acreage along waterways on their farms as environmental "buffer zones."

Siltation and nutrient enrichment from farm and urban water runoff are among the bay's key water-quality problems. As corn production boomed in recent years, many farmers in the Chesapeake watershed expanded fields until they butted close to creeks and streams, exacerbating the runoff problems.

DNR wants farmers who are looking for acreage to take out of production under PIK to look first at areas near waterways. The state is asking them to reestablish natural buffer zones 50 to 200 feet wide where silt, nutrients and farm chemicals can be filtered out by natural cover instead of running off into the bay.

To help, a state cost-sharing program beginning this summer will pay up to 90 percent of the cost of establishing the buffer zones, said Earl Bradley, a DNR coastal zone planner. Bradley said local soil conservation district officers are passing the word to farmers.

One problem the local officials have encountered is uncertainty about the duration of the PIK program, which is expected to continue in 1984, but not guaranteed.

Farmers are reluctant to establish the buffer zones, said Jean Lewis, soil conservationist in Kent and Cecil counties, "when they don't know if PIK will continue next year."

But Brown said steps taken now could blossom into a state program later. He hopes the buffer zones, once in place, could be maintained with state assistance after the PIK program expires. He said DNR envisions management of the buffer zones as wildlife habitat where quail, rabbits and other small game would flourish.