EFFECTS OF HOEINGS AND OF OTHER TREATMENTS ON SUNFLOWER YIELD

One field experiment was carried-out during 1989/90 at Estacao Experim ental Agronomica of Universidade Federal do Rio Grande do Sul, in Eldo rado do Sul, RS, Brazil, with the objective of evaluate the potential injury of hoeings to sunflower. A complete randomized block design wit h six replications was used. Plots were maintained free of weeds durin g the growing season. The treatments tested were early hoeings with me chanical or hand hoeing, hill cultivation, and chemical weed control a lone or combined with late hoeing. Negative effects of hoeings were li mited and difficult to demonstrate; however, hoeings performed early i n the season, during the critical period of weed interference, increas ed sunflower height and number of achenes per plant. Achene yields wer e not affected by treatments. No advantage of using hill cultivation w as observed. Manual or mechanical hoeing were equivalent for all evalu ations.