A field study was conducted in 2002 and 2003 to evaluate the effect of clomazone at 448 g ai/ha plus bensulfuron at 10, 21, 31, and 42 g ai/ha or halosulfuron at 13, 26, 39, and 53 g ai/ha on rice. Herbicide treatments were impregnated onto urea fertilizer and applied at rooting (AR) in a water-seeded production system. Comparison treatments included clomazone AR followed by bensulfuron at 42 g/ha or halosulfuron at 53 g/ha POST. At 7 d after AR (DAAR), rice foliar bleaching decreased from 42% with a single application of clomazone to 23 to 30% with any rate of bensulfuron or halosulfuron impregnated with clomazone. Barnyardgrass and broadleaf signalgrass control did not decrease with the addition of bensulfuron or halosulfuron to clomazone. A single application of clomazone did not control rice flatsedge at 28 DAAR; however, rice flatsedge control was greater than 76% for all bensulfuron and halosulfuron treatments at 28 DAAR. There were no differences in rice yield among herbicide treatments.
Nomenclature: Clomazone; bensulfuron; halosulfuron; barnyardgrass, Echinochloa crus-galli (L.) Beauv. #3 ECHCG; broadleaf signalgrass, Brachiaria platyphylla (Griseb.) Nash # BRAPP; rice flatsedge, Cyperus iria L. # CYPIR; rice, Oryza sativa L. ‘Cocodrie’.
Additional index words: Herbicide tolerance; herbicide-impregnated fertilizer.
Abbreviations: AR, at rooting; DAAR, days after AR; DAT, days after treatment; DPRE, delayed preemergence; fb, followed by.