LIXIVIA??O DO HERBICIDA ACETOCLOR EM SOLO SUBMETIDO à SEMEADURA DIRETA E AO PREPARO CONVENCIONAL

摘要

Avaliou-se a lixivia??o do herbicida Acetoclor (na dosede 3360 g ha-1) em Argissolo Vermelho distróficotípico, submetido à semeadura direta e ao preparoconvencional. Adotou-se delineamento experimentalde blocos casualizados com três repeti??es. Nasparcelas principais encontravam-se os tipos depreparo do solo (semeadura direta e convencional),nas subparcelas as épocas de avalia??o (1, 7 e 21dias após aplica??o do herbicida) e nassubsubparcelas as profundidades de coleta (1-4, 6-9, 11-14 e 16-19 cm). A lixivia??o do herbicidaAcetoclor foi avaliada mediante bioensaio, utilizandoo trigo como planta indicadora (altura e matéria secada parte aérea das plantas). N?o houve diferen?a nalixivia??o do Acetoclor entre a semeadura direta e opreparo convencional nas avalia??es do primeiro aosétimo dias após a aplica??o (DAT). A concentra??odo herbicida Acetoclor foi maior na profundidade de16-19 cm em semeadura direta aos 21 DAT,sugerindo maior lixivia??o do Acetoclor nessesistema de preparo de solo no decorrer do tempo. LEACHING OF ACETOCHLOR HERBICIDE IN SOIL SUBMITTED TO DIRECT TILLAGE AND CONVENTIONALPREPARATION Abstract The Acetochlor herbicide leaching (in dose of 3360 g ha-1) in a Typical Paleudult soil submitted to direct tillage and toconventional preparation was evaluated. The experimental design of casualized blocks with three replications wasadopted. In the main portions the soil preparation types were found (direct and conventional tillage), in the sub-portionsthe evaluation periods (1, 7 and 21 days after herbicide application), and in the sub-portions the samplings depth (1-4, 6-9, 11-14 and 16-19 cm). The Acetochlor leaching was evaluated through a bioassay by utilizing wheat as indicator plant(height and dry-matter of plant aerial parts). It wasn?t found difference in Acetochlor leaching between direct tillage andconventional preparation in the evaluations of the first to the seventh days after application (DAA). The Acetochlorconcentration was higher in the depth of 16-19 cm in direct tillage in 21DAA, suggesting greatest leaching of Acetochlorin this system of soil preparation with the elapse of time.