ABSTRACT The use of ultra-coarse droplets for herbicide application reduces the risk of drift but may compromise the coverage and efficacy of the treatment. The objective of this work was to evaluate the use of ultra-coarse droplets, in different spray volumes, in the application of dicamba herbicide in association with glyphosate, for the control of weeds in two field trials. The first trial was conducted in a 5 x 2 factorial design, with five spray volumes (58, 72, 96, 144, and 177 L ha-1) and two air induction flat-fan spray tips (MUG 110015 - MagnoJet and TTI 110015 - Teejet). The control efficiency of Commelina benghalensis and the spray deposition on the target were evaluated by detecting a tracer using spectrophotometry. The second was conducted in a 2 x 2 factorial scheme, using two volumes (100 and 125 L ha-1) and two tips (MUG 11002 and TTI 11002). The control efficiency of Conyza spp. and fresh matter were evaluated. The different spray volumes and tips did not differ in relation to the deposition of the tracer. The use of ultra-coarse droplets was adequate for weed control. The TTI and MUG tips gave similar and adequate control performance starting at 96 L ha-1. Increasing the volume above 100 L ha-1 did not result in better control.

ABSTRACT One of the main costs in agriculture is related to mechanized operations, which, in turn, are associated with the capital invested in machinery and equipment, the scale of production, and the operating efficiency. Thus, the choice of technology to carry out these operations must take these factors into account to minimize the production cost. In this context, this study aimed to evaluate the most economical investment option for the set of sprayings on a farm located in the municipality of Mineiros, Goiás, Brazil, by comparing two technologies (ground and aerial spraying) and identifying the scale of production that makes each of the technologies more feasible. This study covers the period of one year with the soybean crop in the summer season, followed by the cultivation of corn in the off-season. Economic feasibility indicators were calculated, and the total average costs of both technologies were compared. The results allowed concluding that the investment in aerial spraying with the aircraft acquisition is assertive, as it reduced losses due to crushing. Contracting the service via third parties is feasible and can be used not only in cases of emergency, as it allows for increased profitability.

ABSTRACT For the successful application of phytosanitary products, it is essential to understand the spraying process well. The present work aims to evaluate the spectrum and speed of the droplets produced by different spray nozzle models with air induction, working under different operating conditions. The experiment was conducted using an entirely randomized design with five repetitions in a 3 × 3 × 3 factor scheme that incorporates three nozzle models (ADIA, AIXR, and GA), three nominal flows (0.76, 1.14, and 1.51 L min−1), and three operating pressures (200, 300, and 400 kPa). The spectrum and speed of the droplets were determined directly using a real-time droplet analyzer based on high-resolution image analysis. The spray nozzle model interfered with the results. The ADIA promoted Dv0.5 (VMD) higher than AIXR and GA, reaching differences of up to 90%. The increase in pressure promoted a reduction in the droplet size; however, there was no well-defined behavior for the relationship between the flow rate and droplet size. The ADIA and AIXR gave rise to greater uniformity of the droplets in most of the evaluated conditions. The increase in pressure promoted an increase in the speed of the droplets. However, the effect of the nozzle model on this parameter was dependent on the flow.

ABSTRACT The aim of this study was to evaluate the spectrum and the velocity of droplets produced by nozzles with and without air induction, under different pressures and flow rates. The experiment was conducted in a completely randomized design with five replications, in a factorial 2 x 3 x 3 (two spray nozzles, three flow rates and three operating pressures). The spray nozzles with and without air induction of the Hypro manufacturer (GA and VP) were evaluated, with nominal flow rates of 0.76; 1.14 and 1.51 L min-1 and pressures of 200, 300 and 400 kPa. The spectrum and velocity of the droplets were determined directly, using a Visisize Portable P15 (Oxford Lasers, Imaging Division). The pressure increases further reduction of the VMD and the relative amplitude, and increases the droplet velocity. The droplets generated by the spray nozzles with air induction showed on average amplitude 1.54 times higher than the droplets generated by spray nozzles without air induction. The droplet velocity showed little variation between the nozzles with and without air induction with the same pressure and flow rate, however, spray nozzles with larger flow rates and pressures produced droplets with higher velocities.

ABSTRACT Pesticide drift is an issue in modern farming, mainly for crops under constant spraying as soybeans. This study aimed at assessing drift and pest control for aerial applications in soybean crops. Hydraulic nozzles and rotary atomizers, regulated to a wide spectrum of droplet sizes, sprayed thiamethoxam plus lambda-cyhalothrin using an agricultural aircraft Ipanema 202A at volume rate of 20 L ha−1. Treatments consisted of testing two devices: a rotary cage atomizer (Micronair AU 5000) with blade angles of 65° for larger droplets, and with angle of 55° for smaller ones; and a set of adjustable nozzles (Stol model) with deflector angle of 90° for smaller droplets, and with angle of 30° for larger ones. Drift was evaluated through quantification of active ingredient, by means of liquid chromatography, on nylon strings set 20, 40, 80, 160 and 320 m downwind from the applied area. Control efficiency was measured by counting caterpillars and stinkbugs found five days after spray. Rotary atomizers produced lesser drift compared to adjustable nozzles at the designed setting. Furthermore, drift can be reduced through a suitable regulation of the devices, keeping an effective pest control.

ABSTRACT The aim of this study was to evaluate the spectrum, the velocity and the potential drift risk of droplets sprayed by nozzles with and without air induction, with the addition of mineral oil to the spray solution. The experiment was conducted in a completely randomized design with five replications; in a factorial model 2 × 2 (two spray nozzles and spray solution with and without mineral oil Assist®). Spray nozzles with and without air induction were evaluated, with nominal flow rate of 1.14 L min−1 and pressure of 300 kPa. The spectrum and the velocity of droplets were evaluated directly, using a droplet analyzer (VisiSize D30) in real time based on the analysis of high-resolution images. The drift potential was evaluated in an open circuit wind tunnel. The data were submitted to analysis of variance and comparison test. In general, the addition of mineral oil (1.5% V V−1) resulted in an increase in the velocity of droplets, reduced drift and more homogeneous droplet spectrum. Air induction nozzles promoted larger and less homogeneous droplets, but they little affected the velocity of the droplets. There is an inverse correlation between drift potential and volume median diameter (VMD), which indicates that VMD can be used to predict the behavior of drift risk.

ABSTRACT The effect of blade angle on droplet size spectrum of five rotary cage atomizers and one rotary disc atomizer used in Brazil was evaluated in a high speed wind tunnel, with an air speed of 180 km h−1. This study included the characterization of the droplet size spectrum, via laser diffraction instrument, generated by three blades angles, of 45, 60 and 75 degrees. The spray solution was composed of Picoxystrobin+ Cyproconazole fungicide (SC), at 20 mL c.p. L−1, and at a flow rate of 6 L min−1. As the angle decreased from 75 to 45 degrees, the rotational speed of the atomizers increased and the volume median diameter (VMD) decreased. However, increasing the rotational speed also increased the percentage of droplets smaller than 100 µm (% < 100 µm). At the blade angles of 45 and 60 degrees the atomizers showed that % < 100 µm was higher than 20% and VMD was smaller than 198 µm. The disc type atomizer resulted in the lower values of relative span (RS). The use of 75 degrees blade angle produced the highest values of VMD and the lowest values of % < 100 µm; these parameters were also affected by atomizer model and brand.

RESUMO O objetivo deste trabalho foi investigar o nível de conhecimento de trabalhadores ligados à atividade de aplicação de defensivos agrícolas sobre as funções de adjuvantes de calda e coletar informações sobre os locais de descarte dos resíduos provenientes da lavagem interna do reservatório de calda de pulverizadores, ocorrência e motivos da deriva, nas aplicações de defensivos agrícolas, no Estado do Mato Grosso. As informações foram coletadas por meio das respostas de um questionário entregue aos participantes de um programa de extensão rural, em tecnologia de aplicação, em dezenove municípios produtores de grãos e fibras do Estado. Ao todo, 49,0% dos adjuvantes citados pertenciam à classe dos óleos minerais e 17,9% dos participantes declararam não saber as funções desempenhadas pelos adjuvantes. Os resíduos eram descartados nas lavouras por 58,5% dos participantes. Dentre os participantes que responderam sobre as causas da ocorrência de deriva nas aplicações, 54,1% indicaram problemas relativos às condições climáticas inadequadas. Conclui-se que há carência de conhecimento sobre as funções desempenhas pelos adjuvantes, bem como a ocorrência de descarte de resíduos em locais inadequados no Estado do Mato Grosso. A deriva foi reconhecida como um problema, mas a maioria dos participantes não se propôs a discutir as causas deste tipo de perda.

ABSTRACT This paper aimed at investigating the knowledge level of people working on pesticide spraying activities concerning spray adjuvant properties, as well as collecting information on disposal locations for residues from internal spray tank cleaning, and finally the understanding of pesticide spray drift occurrence in the state of Mato Grosso, Brazil. The information was gathered through a questionnaire answered by participants of a rural extension program in application technology located in nineteen grain and fiber producing regions of Mato Grosso state. Among the mentioned adjuvants, 49.0% belonged to the mineral oil class and 17.9% of participants did not know the functions performed by such products. In addition, 58.5% of the participants discarded residues into the field. Among the participants who answered the question about spray drift occurrence causes, 54.1% indicated problems relating to inadequate weather conditions. In conclusion, there is a lack of knowledge on adjuvant functions, besides of inappropriate residue disposal in the state of Mato Grosso. Spray drift was referred as a problem; however, most of participants were not able to discuss the causes of these losses.

Neste estudo, foram definidas as principais características dos adjuvantes que influenciam e que podem contribuir para compreender o processo de formação de deriva nas pulverizações agrícolas. O experimento avaliou a pulverização de 33 soluções aquosas obtidas das combinações de adjuvantes e concentrações, e quantificou dos mesmos a deriva em túnel de vento e as variáveis denominadas de percentual de gotas menores que 50 µm (V50), percentual de gotas menores que 100 µm (V100), diâmetro mediano volumétrico (DMV), diâmetro de gota tal que 10% do volume do líquido pulverizado é constituído de gotas de tamanho menor que esse valor (DV0,1), viscosidade, densidade e tensão superficial. Os ensaios foram realizados em triplicatas, com pontas de pulverização Tejeet XR8003 VK, pressão de 200 kPa (gotas médias). As soluções pulverizadas foram marcadas com o corante Azul Brilhante a 0,6% (m v-1). O DMV, V100 e a viscosidade causam maior influência no potencial risco de deriva. As características avaliadas e suas respectivas metodologias de determinação apresentam aplicabilidade na avaliação de adjuvantes quanto ao potencial risco de deriva.

This study defined the main adjuvant characteristics that may influence or help to understand drift formation process in the agricultural spraying. It was evaluated 33 aqueous solutions from combinations of various adjuvants and concentrations. Then, drifting was quantified by means of wind tunnel; and variables such as percentage of droplets smaller than 50 μm (V50), 100 μm (V100), diameter of mean volume (DMV), droplet diameter composing 10% of the sprayed volume (DV0.1), viscosity, density and surface tension. Assays were performed in triplicate, using Teejet XR8003 flat fan nozzles at 200 kPa (medium size droplets). Spray solutions were stained with Brilliant Blue Dye at 0.6% (m/ v). DMV, V100, viscosity cause most influence on drift hazardous. Adjuvant characteristics and respective methods of evaluation have applicability in drift risk by agricultural spray adjuvants.

A aplicação terrestre com assistência de ar é bastante difundida. Entretanto, devido às variações climáticas, o rendimento operacional é prejudicado pelas paradas devido à baixa umidade relativa do ar e a altas temperaturas. O objetivo do trabalho foi pesquisar uma forma de umidificar o ar e avaliar a interferência desta umidificação na temperatura e umidade relativa do ar na cortina de vento em pulverizador com assistência de ar. Os tratamentos corresponderam a diferentes vazões de um dispositivo de umidificação, relacionados às condições climáticas. Foram realizadas leituras de temperatura e umidade relativa a 1,0 m para a direita e para a esquerda, do centro da máquina, correspondendo às extremidades da barra central, no centro e na extremidade da barra direita. As leituras foram realizadas, também, em três distâncias na saída da canaleta, sendo uma na saída do ar da canaleta e a 0,25 e 0,50 m da mesma, em sentido ao solo. Os resultados mostraram que a vazão de 0,48 L min-1 no sistema de umidificação proporcionou melhor eficiência em relação à redução da temperatura do ar, apresentando redução média de 2,52 ºC comparado à barra assistida a ar sem umidificação. Já a umidade relativa do ar aumentou em 6,59%, sendo esta a alteração máxima da umidificação injetando 1,92 L min-1. Conclui-se, assim, que a umidificação no duto de ar reduz a temperatura e aumenta a umidade relativa do ar de maneira significativa.

The air-assisted ground spray is fairly widespread. However, due to the unpredictable weather conditions, the operational efficiency is impaired by stops on grounds of low humidity and high temperatures. The aim of this work was to assess an air humidification method and evaluate its impact on temperature and air humidity for the air curtain of the air-assisted sprayer. With respect to relative air humidity, it has increased in 6.59%, being the maximum change when inserting 1.92 L min-1. So, it is concluded that the pipeline humidification might significantly reduce temperature and enhance air humidity. The treatments performed in this study consisted of a varied flow of a humidity device, related to weather conditions. Temperature and relative air humidity were measured at 1.0 m height from right to left of middle point of the machine, corresponding to the end of the spray boom, in the middle and end of right spray boom. The readings were also performed at three different distances from the end of the pipeline and at 0.25 and 0.50 m from that to the soil. The results show that 0.48 L min-1 in the humidification system has promoted a better efficiency in reducing air-temperature, on average 2.52 ºC when compared to the non-humidified one.

O ar incluído em gotas geradas por pontas de pulverização interfere diretamente em seu transporte e deposição, influenciando também na retenção das mesmas após o impacto no alvo. O objetivo deste trabalho foi verificar a interferência de adjuvantes na quantidade de ar incluído em gotas geradas por pontas de pulverização. Os tratamentos utilizados corresponderam a soluções contendo: óleo mineral, óleo vegetal, surfatante e água, aplicados com três tipos de pontas de pulverização, sendo duas com indução de ar e uma com pré-orifício. O ar incluído foi calculado através da diferença entre o volume da mistura pulverizada (ar mais líquido) e apenas o líquido, que foi feito por meio de amostras pulverizadas, capturadas em um funil e coletadas em proveta graduada. A tensão superficial foi estimada através do método gravimétrico, utilizando uma balança de precisão e uma bureta graduada. O surfatante foi o que proporcionou maior porcentagem de ar incluído na pulverização. Para a tensão superficial, as caldas contendo óleo mineral e o surfatante tiveram os menores valores. Os resultados mostraram que o uso de adjuvantes tem influência direta na porcentagem de ar incluído. Além disso, adjuvantes com maior capacidade de redução da tensão superficial e que formam misturas mais homogêneas proporcionaram aumento da porcentagem de ar incluído nas gotas pulverizadas.

The air included in droplets generated by spray nozzles directly int0erferes in transport, deposition and retention of the droplets after its impact on the target. The objective of this study was to analyze the interference of adjuvants in the amount of air included in droplets generated by spray nozzles. The treatments were composed by four spray solutions containing mineral oil, vegetable oil, surfactant and water, and three spray nozzles, two air induction type and one pre-orifice. The air included was calculated by the difference between the volume of spray mix (air plus liquid) and only the liquid, which was made by means of sprayed samples captured in a funnel and collected in a graduated cylinder. The surface tension was estimated by the gravimetric method using a precision scale and a graduated pipette. The surfactant provided the largest percentage of air included in the spray. For the surface tension, the mineral oil and the surfactant had the lowest values. It was concluded that the use of adjuvants had a direct influence on the percentage of air included. In addition, products with greater ability to reduce surface tension and to form homogeneous solutions provided the increase in the percentage of air included in the droplet.

A redução da deriva das pulverizações agrícolas continua sendo um dos maiores desafios da agricultura brasileira. O objetivo deste trabalho foi avaliar o potencial de adjuvantes dos grupos surfatantes, redutores de deriva, óleos minerais e óleos vegetais para a redução da deriva em pulverizações agrícolas. O experimento quantificou a deriva de pulverizações realizadas com 18 adjuvantes em diferentes concentrações, em solução aquosa, sob condições controladas em túnel de vento. Os ensaios foram realizados em triplicatas, com pontas de pulverização Teejet XR8003 VK, pressão de 200 kPa e gotas médias. As soluções pulverizadas foram marcadas com corante Azul Brilhante a 0,6% (m v-1). A deriva foi coletada por meio de fios de polietileno posicionados transversalmente ao fluxo de ar, a diferentes distâncias da ponta e alturas do piso do túnel. A solução de lavagem de cada fio foi processada por meio de espectrofotometria para a quantificação dos depósitos. Os adjuvantes dos grupos funcionais óleos minerais e redutores de deriva proporcionaram valores menores de deriva em comparação com os surfatantes e a água. Os resultados de laboratório indicam que a seleção de produtos e de concentrações adequadas pode reduzir significativamente o risco de deriva nas pulverizações agrícolas. Entretanto, os melhores resultados obtidos em laboratório deverão ser validados com os produtos que irão constituir as caldas de pulverização em condições de campo no futuro.

The reduction of pesticide spraying drift is still one of the major challenges in Brazilian agriculture. The aim of this study was to evaluate the potential of different adjuvant products, such as surfactants, drift retardants, mineral oil and vegetable oil for reducing drift in agricultural spraying. The experiment consisted of quantifying drift of sprayings of 18 adjuvants dissolved in water under controlled conditions in a wind tunnel. Tests were performed in triplicates with spraying nozzles type Teejet XR8003 VK, pressure of 200kPa and medium drops. Solutions sprayed were marked with Brilliant Blue dye at 0.6% (m v-1). The drift was collected using polyethylene strips transversally fixed along the tunnel at different distances from the nozzle and different heights from the bottom part of the tunnel. Drift deposits were evaluated by spectrophotometry in order to quantify deposits. The adjuvants from chemical groups of mineral oil and drift retardant resulted in lower values of drift in comparison with surfactants and water. The results obtained in laboratory show that the selection of appropriate class and concentration of adjuvants can significantly decrease the risk of drift in agricultural spraying. However, the best results obtained in laboratory should be validated with pesticide under field conditions in the future.

Para a otimização no uso de agroquímicos, vários países têm realizado inspeções periódicas em pulverizadores agrícolas. No Brasil, o conhecimento do estado destas máquinas pode nortear pesquisas e investimentos em orientação de uso e de manutenção das mesmas. O objetivo deste trabalho foi verificar o estado de manutenção de pulverizadores em uso para a região norte do Estado do Paraná. Foram avaliados itens como: presença, estado e escala do manômetro, estado das mangueiras, estado dos antigotejadores, presença de vazamentos, estado da barra, estado dos filtros, estado das pontas de pulverização e erros na taxa de aplicação. As máquinas foram caracterizadas como aprovadas quando não havia falha em nenhum item avaliado. O fator que ocasionou o maior índice de reprova entre as máquinas foi a escala incorreta do manômetro, que reprovou 84,55% das máquinas avaliadas. Outro fator de destaque foi a taxa de aplicação incorreta em 75,5% das máquinas. Do total dos 110 pulverizadores avaliados,apenas uma unidade foi aprovada.

To optimize the use of pesticides, several countries have carried out periodic inspections in agricultural sprayers. In Brazil, knowing the conditions of this machinery canguide researches and investments in guidelines for its use and maintenance. The objective of this study was to verify the state of sprayer maintenance used in the North of the state of Paraná, in Brazil. Several sprayer items were evaluated, such as: presence, status and scale of the manometer, status of the hose, status of the anti-drip component, presence of leaks, status of the bar, status of the filters, state of the spraying nozzles and errors in the targeted flow rate. Machines were named as approved when there was no failure in any item evaluated. The factor that caused the biggest level of reprove among the machines was incorrect scale of manometers, which reproved 84.55% of the machines evaluated. Other outstanding factor was the incorrect flow rate in 75.5% of the tested machines. Only one unit was approved from the total of 110 evaluated sprayers.

A ferrugem asiática da soja, causada pelo fungo Phakopsora pachyrhizi, é considerada a principal doença da soja, e, portanto, a escolha e o uso adequado dos equipamentos de pulverização são essenciais para seu controle. O objetivo deste trabalho foi avaliar o desempenho de diferentes equipamentos de pulverização aérea para o controle curativo da ferrugem da soja, utilizando o fungicida Impact 125 SC (flutriafol) a 0,5 L p c ha-1. Os seguintes tratamentos foram avaliados: atomizador Micronair AU 5000 (10 L ha-1 com óleo e 20 L ha-1 sem óleo na calda); atomizador Stol ARD (10 e 20 L ha-1 ambos com óleo) e o sistema eletrostático Spectrum (10 L ha-1 sem óleo a 64 e 71% de umidade relativa). Utilizou-se óleo de algodão (1,0 L ha-1) acrescido de emulsificante BR 455 a 0,025 L ha-1. O ensaio foi realizado na terceira aplicação de fungicidas, quando foram analisadas quatro repetições nas áreas aplicadas e quatro testemunhas não aplicadas para cada tratamento, avaliando-se a severidade da ferrugem, os depósitos de flutriafol nas folhas de soja e o percentual de redução de ferrugem. A análise dos depósitos nas folhas mostrou que não houve diferenças significativas entre os tratamentos. Os melhores controles da ferrugem foram obtidos com os tratamentos Micronair (10 L ha-1 com óleo), Stol (20 L ha-1 com óleo) e o sistema elestrostático (10 L ha-1) com a menor umidade relativa do ar (64 %).

The soybean rust caused by Phakopsora pachyrhizi is considered the main soybean disease and consequently the appropriate selection and the use of spraying equipment are vital for its control. The aim of this study was to evaluate the performance of aerial application equipment for soybean rust control. It was used: Micronair AU 5000 at 10 L ha-1 (with oil) and at 20 L ha-1 (without oil); Stol ARD atomizer at 10 and 20 L ha-1 (both with oil) and Spectrum (electrostatic) at 10 L ha-1 (without oil). The adjuvant was cotton oil (1.0 L ha-1) with emulsifier (BR 455) at 0.025 L ha-1. The field trial was set up at the 3rd fungicide application, when f four replications of each treatment. There were no statistical differences among treatments related to fungicide deposits by at a Confidence Interval of 95%. It was observed that the best results were obtained with Micronair (10 L ha-1 with oil), Stol (20 L ha-1 with oil) and electrostatic system at 10 L ha-1 with the lowest relative humidity (64%).

A seleção de pulverizadores agrícolas que se adaptem às necessidades da propriedade, é um processo trabalhoso, sendo uma das etapas mais importantes dentro do processo produtivo. O objetivo do presente trabalho foi o de desenvolver e utilizar um modelo de programação linear para auxiliar na seleção de pulverizadores agrícolas de barras, baseado no menor custo horário do equipamento. Foram utilizadas as informações técnicas referentes a 20 modelos de pulverizadores disponíveis no mercado, sendo quatro autopropelidos, oito de arrasto e oito do tipo montado. A análise de sensibilidade dos componentes dos custos operacionais mostrou que as taxas de reparo e depreciação foram os fatores que mais interferiram na variação do custo horário do conjunto trator-pulverizador. O modelo matemático desenvolvido facilitou a realização da análise de sensibilidade que foi processada em um tempo muito pequeno.

The selection process of agricultural machines is one of the most important stages of the productive process. The purpose of the present work was to develop and to test a linear programming model to aid in the decision of agricultural boom sprayer selection based on the cheapest hour-cost. The technical information about 20 sprayer models available in the market was used, where four were self-propelled, eight were trailed and eight were lift mounted sprayer. The sensibility analysis of the operational cost components showed that the repair and depreciation rates are the factors that most contribute to hour-cost variation of the sprayer-tractor group. The developed mathematical model facilitated the accomplishment of the sensibility analysis, which was processed in a very short time.