Biological persistence of ametryn diuron and oxyfluoren in two soils under greenhouse conditions. / PersistÃncia biolÃgica de ametryn, diuron e oxyfluorfen em dois tipos de solos sob condiÃÃes de casa de vegetaÃÃo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

This research had the objective of evaluating the biological persistence of three pre-emergence herbicides in two soil types under greenhouse conditions. Oat plants were used as organism test. Two experiments were established: Experiment 1 in the Agronomy Department at Lavras Federal University, Lavras, MG, Brazil, from may to june/2002, and Experiment 2 in the Boliche Experiment Station, âProvÃncia Guayasâ, Equator from october to december/2002. The experimental design were: in Lavras, incomplete blocks, and Boliche split-plots in a 3 x 4 x 4 + 1 factorial, involving three herbicides (ametryn at 2.0 kg.ha-1, diuron at 3.2 kg.ha-1, and oxyfluorfen at 0.48 kg.ha-1); in 0-5, 5-10, 10-15, and 15-20 cm soil layer; sampled at 10, 20, 30, and 40 days after treatment application, plus one untreated check. Plots were constituted of 100 mm diameter PVC pipes filled with undisturbed soil samples from original fields of Boliche (New Inceptisol) and Lavras (Oxissol), planted with 10 oat seeds. Oxyfluorfen inhibited oat seedling number in the 10 days sampled, and inhibited total, shoots and roots dry matter at all soil layer and sample dates, except at 10-15 and 15-20 cm depth at 30 and 40 days samples in Lavras. Oxyfluorfen and diuron promoted the highest toxicity at 14 days after oat seeding in the 10 and 20-days samples. The herbicides did not reduce oat seed emergence in Boliche. Diuron at 0-5 cm soil layer showed the highest oat toxicity and the lowest plant dry matter (total, shoots, and roots) at all sample dates. Oat plant showed good sensitivity to herbicide residues. Diuron was more persistent in the soil

ASSUNTO(S)

herbicide vegetation bioensaio bio-assay herbicida fitotecnia vegetaÃÃo

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