The feasibility of reducing the recommended herbicide rate, single or in mixtures, without affecting any desirable features of soybean ('Santa Rosa') , was studied such as the total dry weight of aerial parts (stem + shoots, leaves and pods) , Leaf Area Index (LAI ) and levels of macro and micro nutrients (Foliar Diagnosis and in the grains). A field trial was settled in a Dark - Red Latossol- sandy phase, at Jaboticabal, São Paulo State, Brazil . The experimental design used was the randomized blocks, with 20 treatments repplicated 3 ti mes, testing the full recommended rate , 25% and 50% reduction of full rate of trifluralin, alachlor and metribuzin, alone and in mixtures. The recommended rates were 0,86; 1, 72 and 0, 28 kg /ha of trifluralin, alachlor and metribuzin, respectivelly. The mixture with low rates, of trifluralin + metribuzin (0 ,6 5 + 0, 21 kg /ha) and alachlor + metribuzin (1 ,44 + 0, 21 kg /h a) , presented control rate higher than 90% up to the 60th day after so wing, without any phytotoxicity or deleterious effects to the soyeban plan ts . It also achieved the best results relating to dry matter content of aerial parts, together with the same mixtures in the recommended rates and weed -free check. The nutrients up take was also greater in this treatments, with higher