Evaluating the Interaction Between Herbicide and Fertilizer Application Timing to Improve Italian Ryegrass Control, Grain Quality, and Yield in Oklahoma Wheat Production
Abstract
Controlling Italian ryegrass (Lolium multiflorum Lam.) is a serious problem for Oklahoma winter wheat (Triticum aestivum L.) producers to face. Italian ryegrass, when not controlled, reduces wheat yield and overall grain quality due to higher than acceptable levels of inert material. The overarching objective of this experiment was to evaluate the interaction between N fertilizer application timing and post-emergence herbicide application timing for control of Italian ryegrass. This interaction will be evaluated based on grain yield, grain quality (protein concentration and dockage in harvested grain), N accumulation in winter wheat and Italian ryegrass, biomass growth, and control of Italian ryegrass. Italian ryegrass was controlled with Axial XL (Pinoxaden) four times, three in the fall during 2011 and once in the fall of 2012 and once in the fall 2012 and twice in the spring of 2013. Tissue samples collect during the 2011-2012 growing season showed an increase in wheat biomass weights when Italian ryegrass populations were controlled. Good growing conditions early in the 2011-2012 growing season allowed wheat biomass to develop and out compete the Italian ryegrass. The greatest Italian ryegrass densities were discovered in the 0 Kg N ha-1 N application rate, poor fertility reduced the competitiveness of wheat. Yields in the weedy plots were slightly lower than the weed free plots that received the same amount of N. Although not significant at all locations between each N rate, the overall grain yields where increase between 37 to 521 Kg ha-1 when Italian ryegrass was controlled in the fall. The results found in the study can be used to better manage herbicide and N inputs for maximum weed control, grain quality, yield, and economic return.
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- OSU Theses [15752]