Cheatgrass control in winter wheat

摘要

An experiment was conducted near Manhattan, KS on a Reading silt loam soil with 2.5 percent organic matter and a pH of 5.7 to evaluate several herbicide treatments for cheatgrass control in "2137" hard red winter wheat seeded with a double disk drill on October 8, 2001. Preemergence treatments were applied to the soil surface on October 8, with 72 F and 59 percent relative humidity. Precipitation of 0.9 inch was received within 1 week after planting, resulting in uniform germination and emergence of crop and weeds. Early fall postemergence (EFP) treatments were applied to 2- to 3-leaf wheat and 1- to 3-leaf cheat and downy brome on November 1 with 68 F, 48 percent relative humidity, and clear skies. Fall postemergence (FP) treatments were appliedto 4-leaf and 2- to 4-tiller wheat, and 1- to 3-tiller cheat and downy brome on November 15 with 67 F, 57 percent relative humidity, and clear skies. Early spring postemergence (ESP) treatments were applied to tillering wheat and weeds on March 16, 2002with 42 F, 49 percent relative humidity, and clear skies. Spring postemergence (SP) treatments were applied to fully tillered wheat and cheatgrass on April 4 with 53 F, 21 percent relative humidity, and mostly clear skies. Treatments were applied with aCO_2 back-pack sprayer delivering 20 gpa at 25 psi through XR8002 flat fan spray tips to the center 6.3 ft of 10- by 20-ft plots. The experiment was a randomized complete block design with three replications. Wheat injury was evaluated November 21 and May 14. Cheat and downy brome control was visually estimated on May 14 and June 7. Wheat was harvested on June 26.