Dairy farmers in the northeast can reduce ammonia emissions from manure by planting winter rye early and applying manure in late fall. This study found that planting winter rye early limited ammonia volatilization and increased nitrogen recovery. The earliest planting date resulted in the highest winter rye biomass, while forage rape yield was higher after all cover crop treatments with manure application. Nitrate-N content in soil was higher in plots with manure compared to those without. Overall, establishing cover crop early and applying manure in late fall can help limit pollution from ammonia loss.