Fairfield County farmer Dave Brandt, who has used winter cover crops on his farm since 1972, talks to Mercer County farmers Tuesday during a cover crop walk at the Mercer Wildlife Area. About 15 farmers attended. Brandt holds an oilseed radish plant, one of several cover crops planted at the wildlife area. Cover crops recycle nutrients in the soil and hold them for spring planted cash crops. Cover crops also aerate and change soil structure by introducing organic matter, lessen soil erosion and compaction and give farmers a place to spread manure in the fall and winter.