Chemical weed control options for zero-tillage spring barley

The need for yearly applications of non-selective and postemergence herbicides was evaluated in zero-tillage barley cropping systems in eastern Québec. The effects of six glyphosate treatments, fall-applied, at several rates and frequencies, and four postemergence herbicide treatments, on weed populations and crop yields, were measured over 2 yr in a zero-tillage spring barley monoculture. Yearly fall applications of glyphosate at rates at or above 0.5 kg a.i. ha−1 combined with postemergence herbicide treatments controlled most weed groups and provided optimum barley yields. Key words: Zero-tillage, no-till, conservation tillage, weed control, barley