Precision planting effect on winter rye yield and quality for biofuel and forage production

Winter rye (Secale cereale) (WR) can be harvested as a biofuel or forage crop to increase farm profitability while reducing soil erosion and mitigating nutrient loss during the fallow period in a corn (Zea mays L.)-soybean (Glycine max L.) rotation. Precision planting, in which the cash crop row is skipped (STCR) to create non-intersecting zones of WR and corn growth, has been introduced to reduce the costs associate with planting of WR and also to alleviate the negative impact of WR on following corn. We conducted five site-years of field experiments in Southern Illinois to compare the impact of STCR versus conventionally planted (intersecting rows of WR with cash crop; NP) WR on biomass, biofuel and forage quality, and economic benefits (potential savings in seed costs with potential for increase in quality of biomass for sale). Our results indicated that STCR had a similar leaf area index (LAI) (1.96) and biomass yield (2.52 Mg ha⁻¹) to NP (1.72 and 2.33 Mg ha⁻¹, respectively). Cellulose and holocellulose (cellulose + hemicellulose) concentrations of WR, which are associated with higher ethanol production, were increased by STCR relative to NP. However, hemicellulose and lignin concentrations were similar between the two planting methods. The STCR decreased forage quality potentially through increased tillering due to the reduction in seeding rate by skipping the cash crop row. Relative forage quality (RFQ) was decreased by the STCR as compared to NP. However, the RFQ in STCR was high enough (>151) that did not influence its economic value. Thus, we recommend STCR over NP for biofuel and forage production.