Revista Brasileira De Herbicidas 2000; 1(3): 213-218
Efficiency of herbicides in preemergence control of weeds in a rice crop
DOI: 10.7824/rbh.v1i3.337
The experiment was developed in 1998/99, in the illTESP Experimental Farm, in Selvíria (MS), on soil with a loamy texture. The objective ofthe present work was to evaluate the tolerance and efficiency ofpreemergence herbicides on rice and observe the effects ofthe treatrnents on the productivity ofthe crop. The rice strain used was Caiapó. The experimental design was a complete randomized block with ten treatments and four replications. The treatrnents were the following: trifluralin (1200 g/ha), oxyfluorfen (120 and 240 g/ha), c1omazone (500 g/ha), trifluralin + oxyfluorfen (1800 + 120 and 1200 + 240 gI ha), c1omazone + oxyfluorfen (500 + 240 g/ha), pendimethalin (1250 g/ha) and controls with and without weeds. The efficiency of the treatments was evaluated in terms of the control of the weeds and the effect of the treatments on the productivity of the crop. The herbicides and doses tested in the experiment provoked symptoms of initial toxicity to the rice plants, which disappear 45 days afie r application and these do not affect the productivity ofthe crop. The main weed species that appeared in the experiment included: Ipomoea acuminata, Commelina benghalensis, Blainvillea rhomboidea and Amaranthus dejlexus. The treatments oxyfluorfen (240 g/ha) and c1omazone + oxyfluorfen (500 + 240 g/ha) provided the best control ofthe studied weed. The interference ofthe weeds reduced the productivity ofthe crop in 56% in relation to the weed free control.
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