Old World bluestem response to fire and nitrogen fertilizers

Old World bluestem (Bothriochloa ischaemum L.) is being extensively established on marginal farmland in the Southern Plains. This 4-year field study in western Oklahoma developed guidelines for burning and N fertilization of Old World bluestem on calcareous and noncalcareous soils. Plots were on 'lron Master' Old World bluestem on a calcareous soil (Quinlan loam, shallow Typic Ustochrepts) and a noncalcareous soil (Carey loam, Typic Argiustolls). On each soil 4 blocks were split (spring burned, unburned) and N treatments (none, urea, ammonium nitrate) and time of N application (early, late) were randomly assigned within each burn treatment. Burning decreased (P