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PALAVRAS-CHAVE Bioensaio Comportamento no solo Precipitação pluviométrica KEYWORDS Bioassay Behavior in soil Rainfall RESUMO:A eficiência no controle de plantas daninhas e o destino de herbicidas no ambiente são influenciados por processos de lixiviação e efeito residual. Diante do exposto, objetivou-se avaliar o potencial de lixiviação e o efeito residual de diuron + hexazinone + sulfometuron-methyl em amostras de solos argiloso e arenoso. Para verificar o potencial de lixiviação, foram aplicados 1,14 + 0,32 + 0,02 e 1,50 + 0,42 + 0,03 kg ha -1 nos solos arenoso e argiloso, respectivamente, em colunas, observando-se o controle de Cucumis sativus nas profundidades de 0-5, 5-10, 10-15, 15-20, 20-25 e 25-30 cm, com simulação de seis precipitações (0, 20, 40, 60, 80 e 100 mm). Na avaliação do efeito residual, foi adotado o esquema fatorial de 2 × 7 + 1, em que avaliaram-se as doses de 1,14 + 0,32 + 0,02 e 1,50 + 0,42 + 0,03 kg ha -1 em ambos os solos, com sete épocas de aplicação (zero, 20, 40, 60, 80, 100 e 120 dias, entre a aplicação e a semeadura do bioindicador), além do controle sem a aplicação. Através de modelo log-logístico não linear, encontrou-se o t 1/2 da mistura formulada. Nas simulações de precipitações superiores a 60 mm, foram observados controles do bioindicador superiores a 90%, em todas as profundidades, em solo arenoso. No solo argiloso, verificou-se a presença da mistura formulada entre 0-15 cm, nas maiores simulações. Houve interação significativa, no efeito residual, entre as doses no solo argiloso com t 1/2 de 100 e 80 dias para a maior e a menor dose, respectivamente. Para o solo arenoso, a interação não foi significativa, com t 1/2 igual a 52 dias. 0-5, 5-10, 10-15, 15-20, 20-25, and 25-30 cm with six precipitation simulations (0, 20, 40, 60, 80, and 100 mm). A 2 x 7 + 1 factorial design was adopted to assess the residual effect, where the doses of 1.14 + 0.32 + 0.02 and 1.50 + 0.42 + 0.03 kg ha -1 were evaluated in both soils, with seven application times (0, 20, 40, 60, 80, 100, and 120 ABSTRACT: Weed control efficiency and herbicide allocation in the environment

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Phytosociological studies are extremely important for the management of weeds in cultivated areas. Thus, the goal of this work was to evaluate the interference of mineral oil associated with oxyfluorfen and flumioxazin, through the phytosociological survey of weeds. Therefore, this experiment was conducted in a 2 x 5 + 1 factorial design and with four replications; the following oxyfluorfen + flumioxazin associations were evaluated: 240 + 50, 192 + 40, 144 + 30, 96 + 20 and 48 + 10 g a.i. ha-1, with and without the addition of mineral oil, including a control sample without application. Thirty days after the application, plant density, frequency and abundance of species were determined, and so were frequency, density and relative abundance, as well as the importance value index. Results indicate that the application of the mixture oxyfluorfen + flumioxazin, regardless of the addition of the mineral oil, provided a great population of Poaceae. The species Digitaria horizontalis and Brachiaria decumbens showed a higher importance value index in all treatments. Families with greater representation as for number of species were Poaceae, Asteraceae, Fabaceae and Rubiaceae. The addition of oil and different doses of the mixture oxyfluorfen + flumioxazin did not affect the population of weeds, compared to the mixture without mineral oil.

-To maintain the quality of the cotton fiber, as well as to provide great yields on the harvest, some aspects must be taken into account such as the uniformity of the bolls and the defoliation; therefore, the use of herbicides and maturators become indispensable. Thus, the objective of this paper was to evaluate the efficiency of the prohexadione-calcium regarding its isolate application and in association with other products in the uniformity and opening of the cotton bolls, as well as the defoliation effect and regrowth of the crop. For such, a field experiment was carried out in the municipality of Diamantino -MT. The outline adopted was of randomized blocks with four repetitions and thirteen treatments, those being composed of control without application; prohexadione-calcium + ethephon + cyclanilide; prohexadione-calcium + flumicloracpentyl; prohexadione-calcium + diuron + thidiazuron; prohexadione-calcium + pyraflufen-ethyl; prohexadione-calcium; prohexadione-calcium + iharol. The treatments were applied when approximately 85% of the bolls of the crop 975 WS were open. The variables: apple opening, regrowth and defoliation were analyzed at 0, 3, 6, 10 and 15 days after the application (DAA) and, finally, the productivity of seed cotton was determined. Regardless of the dose, the plants that received prohexadione-calcium associated with ethephon + cyclanilide, diuron + thidiazuron and pyraflufen-ethyl presented a greater number of open bolls and greater defoliation. We can conclude that the different chemical treatments did not provide statistical differences regarding the regrowth of cotton before the harvest, at 15 DAA, and that the use of prohexadione-calcium, isolated or in association with other products, regardless of the dose, did not influence in the productivity of the seed cotton. Keywords: defoliation; Gossypium hirsutum L.; maturing; uniformity of the bolls Resumo -Para manter a qualidade da fibra do algodão, bem como proporcionar ótimos rendimentos na colheita, alguns aspectos devem ser levados em consideração como, por exemplo, a uniformidade dos capulhos e a desfolha, desta forma, a utilização de herbicidas e maturadores tornam-se imprescindíveis. Assim, o objetivo deste trabalho foi avaliar a eficiência do prohexadione-calcium quando aplicado isoladamente e em associação com outros produtos, na Rev. Bras. Herb., v.14, n.1, p.21-29, jan./mar. 2015 uniformização e abertura dos capulhos do algodão, assim como o efeito na desfolha e rebrota da cultura. Para tanto, conduziu-se um experimento de campo no município de Diamantino-MT. Adotou-se o delineamento de blocos casualizados, com quatro repetições e treze tratamentos, sendo estes compostos por: testemunha sem aplicação; prohexadione-calcium + ethefon + cyclanilide; prohexadione-calcium + flumiclorac-pentyl; prohexadione-calcium + diuron + thidiazuron; prohexadione-calcium + pyraflufen-ethyl; prohexadione-calcium; prohexadione-calcium + iharol. Os tratamentos foram aplicados quando aproximadamente 85% das maçãs da cultivar 975 WS esta...