The present research was conducted in the São Carlos Sugar Mill. Jaboticabal - SP in a oxisol (Latossolic B) containing 3,9% organic matter. with the obje tive to study the behavior of the main post-emergence herbicide mixtures, in the sugarcane crop for weed control, and their interferences on the macronutrient levels and development of CB 41-14 variety. The treatments in kg of active ingredient per hectare were: ametryne + 2,4-D (comercial formulation) at 1,47 -t 2,03; diuron + 2,4-D at 1,60 + 2,16: ametryne + 2,4-D at 1,60 + 2,16; alachlor + 2,4-D at 1,09 + 1,08; asulam + ioxynil 2,4 -D at 2,8 + 1,75; MCPA + 2,4-D at 0,83 + 0,83; oxadiazon 2,4-D at 0,50 + 2,16; ametryne + simazine + 2,4-D at 1,25 1,25 + 2,16; ametryn + secbumeton + 2,4 -D at 2,00 + 2,00 + 2,16; diuron + hexazinone + surfactant at 0,80 + 0,45 + 0,5% and MCPA + 2,3 ,6 -TBA + pendimethalin + surfactant at 1,50 + 0,48 + 0,66 + 0,5% . The weed control was evaluated by counting the surviving weeds, and by visual evaluation according to the scale of the "AssociacionLatinoamericana de Malezas" (ALAM). The effects on the crop were evaluated by counting the fresh-emerging sugarcane plants, visual evaluating of herbicide injuries, analysis of macronutrients levels in the leaves at 5 and 8 months after planting, measures of the lenght of the culms, analysis of fibers, brix, purity and poi and the values of pot/ha and weight of culms/ha. Any interference of the herbicide mixtures. was not observed on the ini tial growth, the average lenght of the culms, the fiber, pol, brix or purity. The best weed control was obtained by the mixtures ametryn + 2,4-D, MCPA + 2,4-D, oxadiazon + 2,4-D, ametryn + secbumeton, diuron + hexazinone and MCPA + 2,3,6 TBA + pendimethalin, and the principal weeds present in the area were Digitaria sanguinalis (L .) Scop, Panicum maximum Jacq., Portulacca oleracea L. and Amaranthus spp. The P content level was reduced by ametryn + secbumeton t 2,4-D and the Ca reduced by diuron + 2,4-D, ametryn ; 2,4-D, alachlor + 2,4-D, asulam + ioxynil + 2,4-D, MCPA + 2,4-D, oxadiazon + 2,4-D, ametryn + simazine + 2,4-D and ametryn + secbumeton + 2,4-D at 5 months. At 8 months no effect on the macronutrient levels was observed. The values of po l/ha and weight of culms/ha were not affected by the treatments when compared with the hoed control, but all treatments yielded less than the hoed control.
post-emergence herbicides; macronutrient levels; sugarcane