S.D. Miller and S. Van Vleet
1996 NCWSS Proceedings, Vol. 51Abstract.
Wheat farmers in Wyoming are concerned with increasing amounts of jointed goatgrass in their fields. Recent shifts to shorter stature wheat varieties and increased use of nitrogen fertilizer has appeared to increase jointed goatgrass infestations in winter wheat. The benefits of banding or injecting fertilizer below the seed compared to surface broadcast fertilizer placement has been previously documented in several crops (including winter wheat). However, no information is available regarding jointed goatgrass response to fertilizer application method. Experiments were conducted at Archer, WY in 1994 to 1995 and 1995 to 1996 to evaluate the influence of fertilizer placement methods on winter wheat growing alone or with jointed goatgrass (30 to 40 plants/yd). Plots were 10 by 40 ft with four replications arranged in a split-plot randomized complete block design. Main plots were fertilizer placement methods and subplots the presence or absence of jointed goatgrass. Fertilizer placement treatments consisted of applying 40 lb/a nitrogen (50% as urea and 50% as ammonium nitrate) in a deep band two inches below and one inch to the side of the wheat row, broadcasting on the soil surface or spoke wheel injecting fertilizer four inches deep and two inches to the side of the wheat row. In addition, an unfertilized check was included as a reference. Jointed goatgrass populations of joints/spike were not influence by fertilizer placement; however, spikes/plant and biomass production were highest in the broadcast fertilizer treatment. The presence of jointed goatgrass decreased winter wheat spikes/plant, seed/spike, 200 seed weight, grain yield and biomass with all fertilizer placement treatments. However, winter wheat was consistently less competitive with jointed goatgrass in the broadcast compared to the spoke wheel or deep band treatment.