The objective of this experiment was to study the effect oftwo water managments, tiliage systems and weed contral on rice yield, water use and water use efficiency and crop yield components. The experiment was conducted in 1993/94 crop growing season in the experimental field ofthe Federal University of Santa Maria, Santa Maria - RS. Rice cultivar BR-IRGA-414 was sowed in rows in December 22, 1993. A factorial (23) experiment in a completely randomized block design was used wiih two irrigation dates (15 and 30 days after emergency - DAE), two soil tillage system (minimum and conventional) and two weed control leveis (with and withoul herbicide appiication). The results indicate that the water consumption was similar among ali treatments. The interaction between irrigation at 30 DAE and minimum tillage results in lower water use efficiency. The number of panicles is higher for irrigation started at 15 DAE than 30 DAE Irrigation starting at 15 DAE presents plants with higher harvest índex, larger panicle number per área and lower spikelet sterilily.
irrigation; herbicides; soil tiliage
