Windrow Burning Eliminates Italian Ryegrass (Lolium perenne ssp multiflorum) Seed Viability

Windrow burning is one of several harvest weed seed control strategies that have been developed and evaluated in Australia to address the widespread evolution of multiple herbicide resistance in annual weeds. Herbicide-resistant Italian ryegrass populations are common in the Palouse region of eastern Washington and northern Idaho. Field and greenhouse studies were conducted to evaluate the effects of burning standing stubble and narrow windrows on the survival of Italian ryegrass seed on the soil surface and to determine the amount of crop residue remaining after both practices. Italian ryegrass emergence was 63, 48, and 1% for the nonburned check, burned standing stubble, and burned windrow treatments, respectively. Crop-residue dry weights were 9.94, 5.69, and 5.79 Mg ha(-1) for these same treatments. Windrow burning can be an effective tactic in an integrated weed management strategy for Italian ryegrass control in the Palouse region of eastern Washington and northern Idaho.