Harvesting Fertilized Rye Cover Crop: Simulated Revenue, Net Energy, and Drainage Nitrogen Loss

Core Ideas: Fertilizing winter rye increased estimated revenue and harvestable biomass. Fertilizing winter rye increased net energy production. Harvesting fertilized winter rye reduced simulated drainage N loss. Rye revenue in response to fertilizer rate plateaued at approximately 120 kg N ha⁻¹. Field studies are needed to evaluate fertilized/harvested rye cover crop. Harvesting fertilized rye (Secale cereale L.) cover crop has been suggested as a method to increase producer revenue and biofuel feedstock production, but drainage N loss impacts are currently unknown. Using the tested Root Zone Water Quality Model (RZWQM) across several N rates, spring application of 120 kg N ha^-1 prior to winter rye harvest reduced drainage N loss by 54% compared with no cover crop and by 18% compared with planted rye that was neither fertilized nor harvested. Estimates of producer revenue and net energy were also positive, with 8.3 Mg ha^-1 of harvested rye biomass. If confirmed by field studies, these results suggest that double-cropping fertilized rye is a promising strategy to increase producer revenue, increase net energy production, and reduce drainage N loss.