(Montana State University - Bozeman, College of Agriculture, 2009) Allen, Thomas Lee; Chairperson, Graduate Committee: Phillip L. Bruckner.
Winterkill has long been a problem for winter wheat growers in Montana. In any given year up to 50% of the seeded acres of winter wheat may have to be reseeded to spring wheat. Research has addressed injury thresholds on when to reseed winter wheat. But little information is available regarding reseeding to spring wheat. The objectives of this study were to determine the level of injury whereby it is more profitable to reseed to spring rather than leave the reduced stand of winter wheat. Eighteen treatments were used to simulate different levels of winter injury and methods of termination of the winter wheat before reseeding. Soil water and nitrogen use by the winter wheat before termination was also determined. Mechanical and chemical termination of 60%, 40% and 20% stands of winter wheat were replanted to spring wheat. An early and late reseeding was also imposed. A 20% stand of winter wheat out yielded the early seeded spring wheat check in all environments. Early reseeded treatments were significantly better than late reseeded treatments. There was no difference between mechanically and chemically terminated plots.
