SPRAYING NOZZLES FOR POST-EMERGENT HERBICIDE APPLICATION IN SOYBEAN

During the 1994/1995 growing season at Goiânia, GO, Brazil (altitude 730 m, 16o41'S, 49o17'W), a field experiment was carried out to study spraying nozzles in post-emergent herbicide spray on soybean crop, and their effects on weed control. Droplets were obtained by hydraulic nozzles 110-SF-01 (70 L.ha-1), D2-23 (75 L.ha-1), 110-SF-02 (139 L.ha-1), D3-25 (132 L.ha-1), 110-SF-03 (208 L.ha-1) and D5-25 (200 L.ha-1). Acifluorfen and bentazon were applied with total coverage on soybean and weed plants. Treatments were assessed by measurements of weed control, phytotoxicity, soybean plant height and grain yield. The variation on spraying nozzles did not influence the weed control among studied plants. Although acifluorfen showed better weed control than bentazon, it was more phytotoxic to soybean plants. The different treatments did not show any harmful effects on grain yield or plant height on the soybean crop. KEY-WORDS: Volume of spray; chemical control; sprayer.