Application of desiccant herbicides on native pasture composed with diferent Paspalum gender

摘要

The objective of this report was to evaluate the effect of desiccant herbicides on native pasture constituted of different species of the Paspalum gender, to adequate it to no-till system or to introduce forage species. Three experiments were carried out in the "Depressão Central Region" in the State of Rio Grande do Sul, Brazil. In the first, during 1995/96, glyphosate was applied in the rates of 360, 720 and 1080g ha-1 of acid equivalent, sprayed at two volumes (50 and 200 ha-1) and the species of Paspalum identified were P. pumilum and P. notatum var. notatum biotypes "C" and "D".. In the second, in 1996, were evaluated glyphosate in rates of 720, 1080 and 1880g ha-1 of acid equivalent, sprayed in the volume of 100 ha-1 and the species of Paspalum identified were P. plicatulum, P. nicorae, P. notatum var. notatum biotype "A", P. pumilum and P. maculosum. In the third, in 1997, glyphosate were evaluated in rates of 180, 270, 360, 450, 540, 720 and 1080g ha-1 of acid equivalent, paraquat in rates of 600 and 800g ha-1 of active ingredient, sprayed in volume of 100 ha-1 and where were identified the P. notatum var. saurae, P. notatum var. notatum biotype "A" and P. pumilum. The use of herbicide glyphosate in rates of 1080, 1440 and 1880g ha-1 is adequate when the control of native pasture is desired to introduce the no-till system. The use of ghyphosate in rates of 180, 270, 360 and 450g ha-1 and paraquat in rates of 600 and 800g ha-1 are adequate when the introducing of forage species is desired. The selection of the herbicides and adequate rate will depend on the predominant Paspalum specie on native pasture.