Cultivar and seeding rates affected the yield and quality of winter rye for biofuel and forage production

Abstract Winter rye (WR; Secale cereale ) can enhance farm profitability and mitigate nutrient and soil loss during the fallow period of a corn ( Zea mays L.)‐soybean ( Glycine max L.) rotation by serving as a biofuel and forage crop. We conducted two trials in southern Illinois to evaluate the effects of seeding rate and cultivar on WR yield, quality, and economic benefits. Study A tested four seeding rates (34, 56, 84, and 112 kg ha −1 ) with six replicates, while study B evaluated two cultivars (Guardian open‐pollinated rye vs. PROGAS hybrid rye) at two seeding rates (67 vs. 101 kg ha −1 ) with four replicates. Results of study A showed that every 10 kg ha −1 increase in seeding rate increased WR biomass yield by 0.07 Mg ha −1 . However, higher seeding rates reduced forage quality, decreasing crude protein, total digestible nutrients, and relative forage quality (RFQ), while increasing cellulose, hemicellulose, and holocellulose contents, which are desirable for biofuel production. In study B, PROGAS (hybrid rye) generally outperformed Guardian (normal rye) in yield, particularly in 2021, across seeding rates with taller plants exhibiting higher lignin, cellulose, hemicellulose, and holocellulose but lower RFQ. Hybrid rye was less cost‐effective for forage production compared to normal rye. We recommend lower seeding rates of normal rye for forage production to optimize quality and hybrid rye at higher seeding rates for biofuel production to maximize biomass yield. These findings highlight the trade‐offs between yield and quality in WR management, offering producers tailored strategies to enhance the profitability of their operation.