EFFECT OF SWATHING AND DESICCATION TIME ON SEED YIELD AND QUALITY OF FLAX

In field studies conducted between 1986 and 1990, flax (Linum usitatissimum L.) was swathed or desiccated with diquat, glufosinate-ammonium and glyphosate at various times between the 0 and 100% brown capsule stages to determine the optimum stage for treatment and extent of seed yield and quality losses from early treatment. Maturity stage, at the maximum value for yield and quality parameters, varied considerably from one test to another. Maximum yield occurred on average at 30% capsule moisture (75% brown capsules) for swathing, 29% for diquat, 26% for glufosinate-ammonium and 17% for glyphosate. Yield reductions for swathing or application of diquat or glufosinate-ammonium ranged up to 32% for earliest treatments, but only to 13% for glyphosate. Seed weight, volume weight and oil content were minimally reduced by early treatment, least by glyphosate, while iodine value was not markedly affected.