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The use of pre-emergent herbicides with prolonged residual effect on the soilis one of the factors that provide great efficiency in the control of the weeds. This study objected to evaluate the residual activity of the formulated mixture diuron + hexazinone + sulfometuron-methyl in different doses in soils of sandy and clayey textures. Two experiments were realized out, one for each soil, adopting the factorial scheme 2 x 8 + 1 with three repetitions. Two doses (0.605 + 0.170 + 0.014 and 1.072.07 + 0.302 + 0.025 kg ha-1 of diuron + hexazinone + respectively) at eight times (0, 20, 40, 60, 80, 100, 120 and 140 days, between the application of the formulated mixture and the bioindicator sowing) and another control without application. At 20 and 40 days after sowing of the bioindicator Cucumis sativus, phytotoxification was carried out. Using the non-linear log-logistic model, the t1/2 of the formulated mixture was determined for the two soils studied. In the soil of clay texture, t1/2 of 101 days was obtained, while for the sandy soil the t1/2 of the formulated mixture was of 52 days, for both doses. The prolonged residual effect on clayey soils may be an essential tool in the management of weeds in sugarcane. However, in sandy soils, smaller doses should be used because of the lower residual effect of the mixture and, consequently, avoid environmental contamination. [ABSTRACT FROM AUTHOR]