EFFECT OF BARLEY, RED CLOVER AND WEEDS ON YIELD AND FORAGE QUALITY OF TIMOTHY DURING ESTABLISHMENT AND SUBSEQUENT PRODUCTION YEARS

Two field studies were conducted between 1983 and 1985. In both experiments, timothy was established in the presence or absence of barley, red clover, grassy weeds and broadleaf weeds. However, data on barley were reported only for one experiment. The stands were harvested once during the establishment year and twice during subsequent years. At each harvest, plot yield, botanical composition and forage quality were evaluated. Seeding with barley precluded forage harvest during the establishment year and reduced yield by 13% in the following year. Barley had little effect on the quality of the forage harvested in the subsequent year. During establishment, the timothy-red clover mixture produced a lower timothy yield than the pure stand of the grass. But, in terms of total yield, the mixture was beneficial. In the subsequent years, the mixture yielded more than the pure stand when the pH was 5.4 while pure timothy yielded more than the mixture when the pH was 4.5. In all cases, red clover improved forage quality. In the year of establishment, the presence of weeds increased total biomass harvested. However, in these conditions, the growth of timothy and red clover were reduced, particularly by annual broadleaf weeds, and the quality of the forage was lessened, especially by annual grassy weeds. The lack of weed control during establishment had a residual effect in the first production year; grassy weeds reduced total yield by 15% while broadleaf weeds reduced yield by 30%. In the second production year, the growth of the perennial broadleaf weeds compensated for the yield losses observed in the previous year and increased forage quality.Key words: Broadleaf weeds, grassy weeds, Phleum pratense, competition, crude protein, acid detergent fiber