The adoption of dicamba-tolerant soybean varieties has increased the concern and demand for new drift and volatility reduction technologies. Potential spray nozzles and adjuvants should be studied to determine its effects on drift and volatility of dicamba tank-mixtures. The objective of this study was to evaluate physicochemical characteristics of spray solutions containing dicamba; to analyze droplet size effect with air induction nozzles; and to assess dicamba volatilization on soybean plants with a proposed methodology. Treatments included dicamba only and mixtures with herbicides and adjuvants. Dicamba mixed with lecithin + methyl soybean oil + ethoxylated alcohol adjuvant had the greatest efficacy potential among treatments considering tank-mixture pH, surface tension, contact angle and droplet size. The MUG11003 nozzle produced the coarsest droplet size and was better suited for drift management among nozzle types. The proposed volatilization methodology successfully indicated dicamba volatilization in exposed soybean plants and among the evaluated treatments, it showed greater volatilization for dicamba with glyphosate + lecithin + propionic acid adjuvant.

The spraying of herbicides in crops has become the main form of weed control. Although it means unexpected effects on non-target plants resulted by spraying drift. Thus, improvements in application techniques, as the best selection of spray nozzles and adjuvant, are essential to avoid environmental contamination and economic losses. On this work, we evaluate how much adjuvant associated with nozzles can reduce the spray drift. The nozzles used at experiment were air induction flat tip, hollow cone and twinjet and the spray liquids, which were composed of herbicide glyphosate and phosphatidylcholine + propionic acid adjuvant. Measurements were made at wind tunnel and droplet sizer, at laser diffraction method. The models of nozzles influence in droplet size characteristics and in occurrence of spray drift. The use of adjuvants reduces the spray drift only combined with the twinjet nozzle, while for the other models the adjuvant did not reduce the global spray drift at significant levels. The adjuvant reduced the spray drift until 39%, while the nozzles model reduced until 74%. Both techniques when combined were able to reduce until 80%. The model of nozzle has the biggest result on drift mitigation and the use of adjuvants can increase the drift mitigation specially with nozzles that produces smallest droplets.

RESUMOO objetivo do presente trabalho foi avaliar a cobertura da cultura da soja na aplicação de fungicida em função de pontas de pulverização (ponta de jato cônico e duas pontas de jato plano anexado a um corpo de bico DUO) e três volumes de calda (100, 150 e 200 dm 3 ha -1 . Para a pulverização com bicos hidráulicos foi utilizado um pulverizador costal de pressão constante mantida por CO 2 comprimido com barra de 2 m. A análise da porcentagem de cobertura foi realizada por meio da utilização de papel hidrossensível, sendo que, esse foi colocado em três posições da planta o que representa, em altura, os terços superior, médio e inferior do dossel. Para todos os terços não houve interação entre os fatores avaliados, assim como também não houve diferença estatística entre as pontas de pulverização e entre os volumes de calda. Em relação aos volumes de aplicação o de 200 dm 3 ha -1 apresentou maior porcentagem de cobertura. Palavras-chave: Tecnologia de aplicação; jato plano; jato cônico; ferrugem asiática. ABSTRACTThe goal of this research was to evaluate two tips of spraying nozzles (hollow cone nozzle and two flat fan nozzle annexed to a nozzle body DUO) and three spray volumes (100, 150 and 200 dm 3 ha -1 ), whose application was for the control of the Asian soybean rust. An area of 288 m 2 was used, with a randomized blocks design in a factorial 2x3 with 4 repetitions, total of 24 experimental parcels of 12 m 2 . For the spraying with hydraulical nozzles a costal spray of constant pressure kept by CO 2 compressed with bar of 2 m was used. The analysis of the covering percentage was carried through by means of the use of hidro-sensible paper, that was placed in three position of the plant what it represents, in height, the third superior, average and inferior of the canopy. For both the third no interaction between the evaluated factors, was found and meither difference statistics between the spraying tips and the volumes. In absolute values the twin flat fan nozzle DUO presented minimum difference of covering in relation to the hollow cone nozzle, and for the spray volume of 200 dm 3 ha -1 presented greater covering percentage.

RESUMO:O presente trabalho teve por objetivos avaliar o espectro de gotas e os perfis de distribuição volumétrica de um bico hidráulico de jato plano de faixa expandida, modelo XR11003. Utilizou-se de analisador de partículas a laser para avaliar o espectro de gotas e de mesa de deposição para análise da distribuição volumétrica. O ensaio do espectro de gotas foi em delineamento inteiramente casualizado, em esquema fatorial 2 x 2 x 3, com três repetições, em que o primeiro fator representa o líquido pulverizado (L1 = água e L2 = água + 0,1% de espalhante adesivo não-iônico), o segundo representa a pressão de pulverização (P1 = 200 kPa e P2 = 400 kPa) e o terceiro representa três bicos hidráulicos XR11003 de jato plano (B1, B2 e B3). No ensaio de distribuição volumétrica, o delineamento foi o inteiramente casualizado, em esquema fatorial com dois fatores, não se avaliando o fator bico. Dos resultados do espectro de gotas, observaram-se maior tamanho de gotas para a pressão de 200 kPa e menor amplitude relativa quando se utilizou 0,1% de adjuvante. Para os perfis de distribuição volumétrica, ocorreu aumento na faixa de deposição e no espaçamento entre bicos com C.V. de 10%, com a adição de 0,1% de adjuvante e aumento na pressão. PALAVRAS-CHAVE:surfactante, líquido de aplicação, tecnologia de aplicação. VOLUMETRIC DISTRIBUTION AND SPECTRUM OF DROPS OF HIDRAULIC NOZZLES OF PLANE JET OF EXPANDED STRIP XR11003ABSTRACT: The present work had for objective to evaluate the spectrum of drops and the volumetric distribution of a hydraulic nozzle of a plane jet of expanded strip, model XR11003. A laser particle analyzer was used to evaluate the spectrum of drops and a deposition table was used for analysis of the volumetric distribution. The experiment of the spectrum of drops was a completely randomized design, factorial 2 x 2 x 3, with three repetitions, where the first factor represents the sprayed liquid (L1 = water and L2 = water + 0,1% of no-ionic surfactant), the second factor represents the application pressure (P1 = 200 kPa e P2 = 400 kPa) and the third factor represents three nozzles XR11003 of the plane jet (B1, B2 e B3). The experiment of volumetric distribution was completely randomized design, factorial 2 x 2, not evaluating the factor nozzle. The results evidenced larger size of drops for the pressure of 200 kPa, and smaller relative width when it was used 0,1% of adjuvant. For the profiles of volumetric distribution, it increased the deposition strip, and in the spacing among beaks with C.V. of 10%, with the addition of 0,1% of adjuvant and increasing in the pressure.