Rye-soybean double-crop: planting method and N fertilization effects in the North Central US

Abstract Double-cropping winter rye cover crops (CC) with soybean in the North Central US could help global effort to sustainably intensify agriculture. Studies addressing management of these systems are limited. Therefore, a field study was conducted from 2017 2019 Iowa, evaluate CC biomass production, aboveground N accumulation, estimated economics, within-field energy balance and greenhouse gas (GHG) emissions under three application rates (0, 60, 120 kg ha ?1 ) planting methods (pre- post-harvest broadcast drilling). Averaged over rates, all resulted >5.0 Mg year dry matter. 2-year compared unfertilized treatments, applying 60 produced 1.1 more (6.1 vs 5.0 ), accumulated 30 (88 58 led 20 GJ net energy. Biomass production not significantly higher rate. Even when accounting for an 0.75 above ground left after harvesting, removed than applied at The minimum prices needed double-cropping be profitable (breakeven prices) averaged $117 $104 0 which factors yield reductions local averages but off-site transportation. GHG were increase approximately threefold between without considering bioenergy offsets. While environmental tradeoffs need further study, results suggest harvesting fertilized before is promising practice maximize total crop production.