Species, seeding rate, and planting method influence cover crop services prior to soybean

Small grain cover crops can be planted utilizing different methods. Due to their tillering capacity, seeding rates lower than current recommendations may offer adequate weed suppression and ground cover while they are growing. In 2 yr of field experiments, soft red winter wheat (Triticum aestivum L. ‘Pembroke’) and cereal winter rye (Secale cereale L. ‘Aroostook’) cover crops were planted following corn (Zea mays L.) by drilling or broadcasting 112 or 34 kg germinable seed ha^–1 to examine how seeding rate and planting method influence plant establishment and density, biomass accumulation, winter weed suppression, and percent ground cover. Weather and soil conditions influenced cover crop biomass and ground cover produced by the two species planted at different rates using different methods, and thus subsequent weed suppression. When soil conditions were dry at and after planting, drilling seed led to higher plant density, cover crop biomass, percent ground cover, and lower weed biomass. In both years, cereal rye generally produced more biomass than wheat and contained less winter weed biomass. After a colder-than-average winter, percent ground cover with cereal rye was maintained at a higher level than with wheat. The higher seeding rate resulted in more ground cover, but did not affect winter weed biomass and did not consistently affect cover crop biomass. Generally, treatments that had more cover crop biomass also had higher percent ground cover and less winter weed biomass.