Ng. Fleck et Ra. Vidal, EFFECTS OF PHYSICAL METHODS OF WEED-CONTR OL ON SUNFLOWER AGRONOMIC CHARACTERISTICS, Pesquisa agropecuaria brasileira, 28(11), 1993, pp. 1307-1318
During the 1990/91 season a field experiment was carried out at Estaca
o Experimental Agromomica of Universidade Federal do Rio Grande do Sul
, in Eldorado do Sul, RS, Brazil, in order to investigate effects of p
hysical methods, others than weed control, on suflower agronomic chara
cteristics. To compare treatments a split-plot design, was used where
the main plots received or not nitrogen side-dressing (80 kg/ha of N),
and on the subplots methods of weed control were applied. These treat
ments consisted of various modalities: early hoeings performed by hand
(with or without hill cultivation) or mechanically; early postemergen
ce chemical control followed by late hand hoeing, or weed pulling, or
oat residue mulching; and a weedy check. Sunflower traits were little
affected by phsical methods and additional effects of hoeing were limi
ted. No difference was found between hoeing performed manually or mech
anically, and neither between early and late operations. The practice
of hill cultivation did not affect characteristics investigated. Oat r
esidue mulch presented negative effects, decreasing sunflower yield.