The Maryland Department of Agriculture has approved more than half a million acres of winter grains in the state's cover crop program, a record that officials said would protect both the land and the Chesapeake Bay.

Small grains such as wheat, rye or barley are planted as cover crops in the fall to draw on unused nutrients, control soil erosion and limit runoff to the bay and its tributaries.

Gov. Martin O'Malley, appearing Thursday at a farm in Cordova on the Eastern Shore, announced that the state had approved a record 502,323 acres of winter grains – one and half times the two-year milestone – requested by a record 1,688 farmers.

Appearing with Agriculture Secretary Buddy Hance, O'Malley said the state had received a $600,000 grant to use remote field sensors to determine how efficiently cover crops are taking up nutrients. Farmers will receive reports on their fields so they can better manage the cover crop.