Weed management at the time of perennial cereal rye establishment
Perennial cereal rye (PC rye) is a new crop that is being developed at the Lethbridge Research Centre for the production of silage for cattle. Its ability to compete with weeds during establishment and tolerance to herbicides for weed control was unknown. Therefore, experiments were established with PC rye, and several herbicide treatments were applied to test crop tolerance and weed control. PC rye was not injured by bromoxynil/MCPA, 2,4-D, thifensulfuron/tribenuron, fenoxaprop, clodinafop-propargyl, and tralkoxydim. Combinations of herbicides for broadleaf weed control and annual grass control usually reduced weed dry matter (DM) to < 5 g m-2 in the establishment year. Weeds made up 20 to 36% of the total DM when herbicides were not applied. However, this level of weed content did not affect the digestibility of the forage samples or the total DM produced as weed DM compensated for reduced PC rye yield in weedy plots. Also, the presence of weeds during establishment of PC rye did not affect weed content or PC rye yields the year after establishment. Key words: Acid detergent fibre, digestibility, neutral detergent fibre, perennial cereal rye, weed control, yield