Altai wild ryegrass yield response to herbicides applied during establishment
The effects on productivity of Altai wild ryegrass (Leymus angustus (Trin.) Pilger) of 14 herbicide treatments applied during establishment were investigated in two field experiments at Melfort, Saskatchewan. Weed control achieved with metsulfuron, chlorsulfuron, thifensulfuron and tank-mixed applications of bromoxynil with diclofop or fenoxaprop during the establishment year ensured satisfactory forage establishment which in turn caused a "residual effect" for 1–3 yr increasing individual cut as well as cummulative forage dry matter yields significantly. When established with a heavy broadleaf weed infestation (138 m−2) dominated by stinkweed (Thlaspi arvense L.) in 1985, bromoxynil plus diclofop increased yield 359% over a 3-yr period. Sulfonylurea herbicides increased yield 221–346%. Bentazon and MCPA/mecoprop/dicamba increased yields 85%. With a moderate weed infestation (40 m−2) dominated by lamb's-quarters (Chenopodium album L.) in 1986, sulfonylurea herbicides and bromoxynil plus the graminicides increased cummulative yields only 37–59%. Sethoxydim and fenoxaprop, tested alone, caused significant crop injury in both experiments. Key words: Altai wild ryegrass, Leymus angustus (Trin.) Pilger, herbicide, weed control, forage yield