Celery (Apium graveolens L.) and weed response to cover crops and nutrient management on muck soil

Michigan ranks second in the nation for celery production. Most of Michigan celery is produced under intensive systems with limited crop rotation. Many celery growers are increasingly interested in sustainable practices, such as the use of cover crops, to reduce external inputs, suppress weeds, enhance soil quality, and improve yield and quality. This study was undertaken to assess the potential to integrate cover crops into intensive celery production systems. Specific goals were to measure celery growth and yield under different cover crops, evaluate the effects of the cover crops on soil fertility, measure the weed suppressiveness of the cover crops, and determine if the cover crops can enable growers to reduce fertilizer inputs. Our results indicated that cover crops could fit into celery cropping systems, especially for early planted crop that is usually harvested between July and August. Oilseed radish and mustard species showed the greatest benefit, both at the research station and at a grower's farm compared with rye or hairy vetch. Celery growth and yield was enhanced by oilseed radish. Hairy vetch (a legume) failed to improve nitrogen concentration in the soil primarily because of low nodulation under muck soil. On the other hand, oilseed radish recycled large amount of potassium and nitrogen. All cover crops studied suppressed weed early in the season with oilseed radish providing the greatest effect. Combining oilseed radish with different fertilizer rates showed that growers can potentially reduce their fertilizer inputs by up to 50% without any yield reduction.