Evaluating Starter Fertilizer Sources in Organic No-till Maize Production.

Cover crop mulches provide an excellent weed control mechanism in organic no-till maize production. Additional fertilization may be required to achieve maximum maize yields in a system using cover crop mulches for weed suppression. This study was conducted to evaluate different starter fertility sources in organic no-till maize production. This experiment was employed in Kinston and Salisbury, NC and Beltsville, MD from 2012-2013. A cereal rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth) cover crop mixture was grown prior to maize planting across all treatments. Cover crops were terminated at maize planting using the roller-crimper. Fertility treatments included a broadcast poultry litter application, subsurface banding of both pelleted poultry litter and pelleted feather meal using the dry fertilizer boxes on the planter, and one treatment receiving no additional fertility beyond that provided by the cover crop mixture. Both weedy and weed free conditions were maintained across all fertility treatments. At Salisbury and Beltsville, our high fertility sites, yields were similar between all fertility treatments. At Kinston, our lower fertility site, the highest yields were achieved with the broadcast poultry litter application. The broadcast treatment had 107% higher yields compared with the subsurface banded feather meal material, which had 8% and 168% higher yields compared to the subsurface banded pelleted poultry litter treatment and the no additional fertility treatment, respectively. At our low fertility site, weed coverage was lowest in the broadcast fertility treatment. The subsurface banded fertility sources also provided for reduced weed coverage compared to the no additional fertility treatment at the lower fertility site. Despite comparatively large increases in N provision from the feather meal material, yields were similar between the two subsurface banding methods at all locations. The baseline fertility of the site will determine the advantages in a broadcast poultry litter application over using a subsurface banding approach.