Double Cropping of Corn Silage Rotations with Winter Cereals As Forage Crop.

Double cropping of corn (Zea mays L.) silage with cereal rye (Secale cereal L.) or triticale (x Triticosecale Wittm.) has the potential to increase on-farm forage production as well as provide environmental benefits such as erosion control, end-of-season nutrient uptake, increased soil organic matter and rotation diversity. Here we report on forage yield ranges and optimum economic rates of nitrogen (OERN) for cereal rye and triticale grown in New York corn silage rotations. The winter cereals were planted after corn harvest at 58 locations (42, 14, and 6 locations in yr 1, 2, and 3, respectively) varying in soil types, soil fertility and field management. Of the locations, 36% were cereal rye and 64% were triticale. Nitrogen was applied at dormancy break at five rates (0, 34, 67, 101, and 134 kg N ha^-1) in four replications per location. Trials were harvested at flag leave stage in May of each year and yield, dry matter (DM) content, and OERN were determined. Cereal rye averaged 3.6 Mg DM ha^-1, and triticale yield averaged 4.5 Mg DM ha^-1. The OERN averaged 65 kg N ha^-1 for cereal rye and 59 kg N ha^-1 for triticale. However, 24% of the cereal rye plots and 38% of the triticale plots did not respond to N addition, while 48% of cereal rye and 35% of triticale plots needed 78 to 100 kg N ha^-1 for optimum yield. Economic analyses showed break-even winter cereal yields of 1.7 (no N needed) and 2.3 Mg DM ha^-1 (if the OENR is 84 kg N ha^-1), assuming no impact of incorporation of the winter cereal in the rotation on corn silage yields. The break-even winter cereal yields were 3.8 (no N needed) and 4.5 Mg DM ha^-1 (if the OENR is 84 kg N ha^-1), when assuming a reduction in corn silage yield of 2.2 Mg DM ha^-1. Of the cereal rye fields, 95, 86, 52, and 24% exceeded 1.7, 2.3, 3.8, and 4.5 Mg DM ha^-1, respectively. For triticale, 97, 97, 65, and 51% of the fields exceeded 1.7, 2.3, 3.8, and 4.5 Mg DM ha^-1, respectively. Double cropping with winter cereals in corn or sorghum rotations is a promising way to provide additional, high quality forage. Work is ongoing to identify when additional N through fertilizer or manure can increase yields and under what conditions yields that exceed break-even yields can be obtained.