The daikon radish, a staple at sushi bars worldwide, is helping Maryland farmers fight Chesapeake Bay pollution. Some farmers are experimenting this winter with using the radish as a cover crop, which is planted in the fall to absorb excess fertilizer and prevent it from running off into waterways while helping control erosion and improve the soil. In Talbot County, which led the state in cover crop planting last year, wheat is most often planted, but county officials say some farmers are experimenting with the slender, white, deep-rooted radish. State officials say the radish’s roots help break up compacted soil and reduce weeds, and the plants break down if the radishes are not harvested. That means spring planting can be done without plowing under the cover crop.