By Blake Jackson
Terminating cereal rye or triticale by chopping before anthesis is generally ineffective, with Penn State research showing up to 80% regrowth at the late-boot stage and 50% at mid-heading. Pre-harvest herbicide application for forage rye is illegal.
Therefore, post-harvest herbicide application is the best approach. Glyphosate (1.13 lb ae/ac) typically provides better burndown than contact herbicides like paraquat for post-harvest termination.
Delaying termination after harvest to encourage regrowth is likely unnecessary with glyphosate, provided sufficient green leaf tissue remains after cutting for herbicide absorption and weather conditions are favorable (above 55°F) for uptake and movement within the plant.
Effective cover crop termination strategies require consideration of weed presence and the cover crop species. A dense cover crop often suppresses weeds, but herbicide-resistant species like horseweed may still be present, necessitating adjustments to the burndown program and application timing for optimal weed control.
For legume and brassica cover crops, incorporating synthetic auxins like dicamba or 2,4-D LVE into glyphosate or paraquat tank mixes has consistently improved control in Mid-Atlantic field trials.
It's crucial to understand pre-plant application restrictions for all tank-mix partners in both corn and soybean cropping systems.
Herbicide labels contain vital information regarding application timing and rates, which can be influenced by cover crop termination timing and soybean seed trait technology (e.g., Enlist 3, Xtend, XtendFlex, LibertyLink).
Careful attention to these restrictions ensures effective cover crop termination and prevents unintended consequences for the subsequent cash crop.
Developing a successful burndown program hinges on identifying existing weeds, selecting appropriate tank mixes for the cover crop species, and adhering to all herbicide label restrictions.
Categories: Pennsylvania, Crops