This work aimed to evaluate static superficial tension, pH and foam production in glyphosate + chlorimuron-ethyl tank mixtures with or without adjuvants. The experiment consisted of two stages, with the first stage being arranged in a complete randomized design, with six treatments and 20 replications, represented by glyphosate (540.0 g a.e. ha-1) and chlorimuron-ethyl (7.5 g ha-1) solutions, isolated and in tank mixtures in the following formulations: PolarisTM, Roundup ReadyTM, ClassicTM, PolarisTM + ClassicTM, Roundup ReadyTM + ClassicTM and check (water). The second stage was also arranged in a complete randomized design, with 70 treatments and 20 replications, in a 2 x 5 x 7 factorial scheme constituted by two mixtures of glyphosate with chlorimuron-ethyl (PolarisTM + ClassicTM and Roundup ReadyTM + ClassicTM), 5 adjuvants (Joint OilTM, NimbusTM, AssistTM, Natur' OilTM and Agr' ÓleoTM) and 7 adjuvant doses (0.000; 0.031; 0.062; 0.125; 0.250; 0.500 and 1.000% of v/v). PolarisTM and Roundup ReadyTM solutions , isolated or in tank mixtures with ClassicTM, characterized by static superficial tensions of 43.2 and 35.9 mN m-1 and medium pHs, around 4.5 to 4.6, respectively. PolarisTM + ClassicTM, Roundup ReadyTM + ClassicTM and ClassicTM solutions showed the highest foam quantity and persistence during the time, compared to PolarisTM and Roundup ReadyTM mixtures. Adjuvants promoted reduction of static superficial tension when associated with PolarisTM + ClassicTM and Roundup ReadyTM + ClassicTM mixtures, being characterized in efficiency by this decreasing order: NimbusTM (36.5% and 25.8%) < Joint OilTM (32.2% and 25.2%) < Agr' OilTM (21.2% and 13.4%) < Natur' OilTM (17.4% and 10.6%) < AssistTM (8.5% and 10.6%). Adjuvants promoted reduction of foam quantity and persistence in the PolarisTM + ClassicTM and Roundup ReadyTM + ClassicTM mixtures, with small variations in the medium levels of pH of the solutions lower than 0.5.
pH; foam; herbicide; stability
