Mauri Martins Teixeira

Avaliação do espectro de gotas de pontas de pulverização hidráulicas utilizando a técnica da difração do raio laser

The spray nozzles are one of the most important components of pesticide hydraulic sprayer. This study evaluated the droplet spectrum of hydraulic flat fan (standard and low drift) and hollow cone spray nozzles, available in the market, under different working pressures. In laboratory, droplet spectrum, using a real time laser particle size analyzer, was measured with the operating pressure of 200; 300 and 400 kPa, for flat fan, and 400; 500 and 600 kPa, for hollow cone. The results showed that: the droplet spectrum was affected by the nominal flow and by the liquid pressure; the drift potential of standard flat fan and hollow cone spray nozzles was high; the use of low drift nozzles increased the droplet diameter, which was an effective factor in drift reduction, and the technique of laser diffraction provides a robust means of measuring the droplet size produced by spray systems.

Distribuição volumétrica e espectro de gotas de pontas de pulverização de baixa deriva

Objetivou-se neste trabalho avaliar a distribuicao volumetrica e o espectro de gotas das pontas de pulverizacao de baixa deriva TTI110015, AI110015 e AVI11001 sob diferentes condicoes operacionais. A distribuicao volumetrica foi determinada em bancada de ensaios padronizada analisando o coeficiente de variacao (CV%) de uma barra simulada em computador, utilizando pressoes de 200, 300 e 400 kPa, altura de 30, 40 e 50 cm em relacao a bancada e espacamento entre pontas de 40 a 100 cm. O espectro de gotas foi produzido utilizando-se apenas agua como calda em um analisador de particulas em meio aquoso, nas pressoes de 200, 300 e 400 kPa. Foram avaliados o DMV, a porcentagem de gotas com diâmetro inferior a 100 µm (%100 µm) e a amplitude relativa (AR). As pontas proporcionaram perfil descontinuo nas pressoes de 300 e 400 kPa e uniforme a 200 kPa. Na pressao de 200 kPa, as pontas foram adequadas apenas para aplicacao em faixa, e a 300 e 400 kPa, apenas para area total. Ocorreu menor CV (abaixo de 7%) com a maior pressao de trabalho e menor espacamento entre pontas. A medida que se aumentou a pressao de trabalho, reduziu-se o DMV. As pontas TTI110015 e AI110015 em todas as pressoes e a ponta AVI11001 na pressao de 200 kPa produziram gotas extremamente grossas e gotas grossas nas pressoes de 300 e 400 kPa apenas para a ponta AVI11001. As pontas proporcionaram baixos valores de amplitude relativa (AR) e gotas de tamanho uniforme, bem como produziram baixa porcentagem de gotas menores que 100 µm, principalmente TTI110015 e AI110015, com menor risco de deriva.

Deposição e deriva de calda fungicida aplicada em feijoeiro, em função de bico de pulverização e de volume de calda

The fungicide application technology should provide efficient control of vegetable diseases. The objective of this study was to evaluate the deposition and the drift of fungicide sprayed in a common bean crop with different nozzles and two volumes of application. A completely randomized block design with four replications was used, in a factorial model 2 x 2: two spray nozzles (standard flat fan and hollow cone) and two spray volumes (125 and 250 L ha-1). The study of deposition was made by a tracer analysis in different positions of the crop, using spectrophotometer. The drift was evaluated using artificial targets placed outside the application area. The fungicide, with the tracer was applied three times, using a CO2 - pressurized sprayer. The results allowed the following conclusions: the flat fan and hollow cone nozzles provided similar cover of the bean leaves, both in the superior and the inferior position of the crop; the application volume of 250 L ha-1 provided higher retention of fungicide in the leaves and higher uniformity of coverage of the plants than the volume of 125 L ha-1; the droplets formed in the application with hollow cone nozzles were more favorable to the drift than the ones produced with flat fan nozzles, specially when low application volume was used; and the applications, in general, provided low deposition uniformity and high drift potential.

Características técnicas de pontas de pulverização LA-1JC e SR-1

This study aimed to evaluate the technical characteristics of LA-1JC and SR-1 skim nozzles, at different pressures and spray boom heights. Each nozzle distribution profile, volumetric distribution quotient in one spray boom, rate, volumetric median diameter (VMD), numeric median diameter( NMD),coefficient of homogeneity, nozzle symmetry index and left, right and total opening angles were evaluated at 100, 200, and 300 kPa. Nozzles showed continuous profile at 100 kPa for SR-1 nozzle and at all pressures for LA-1JC nozzle. The SR-1 nozzle showed discontinuous distribution profile at pressures 200 and 300 kPa. The best profile for both nozzles was verified when nozzles were smaller, and pressures and boom height were higher. Increased opening angle and rate were observed with increased pressure in both nozzles. The drop spectrum obtained is adequate to systemic herbicide application in post-emergence and to herbicide applied in preemergence. LA-1JC at 100 kPa and SR-1 at all pressures should not be used in nozzle overlapping at 100 kPa.

Características técnicas de bicos de pulverização hidráulicos de jato plano

The use of spray nozzles that provide a homogeneous covering with uniform droplet spectrum is important to obtain an efficient pesticide application, without damage to the environment. Thus, the principal aim of this work was to evaluate the technical characteristics of four hydraulic spray nozzles available in the market, under different working pressures and positions in relation to the objective, seeking to supply indicators for a correct selection of spray nozzles. In a controlled atmosphere, the following parameters were determined: distribution profile, the flow, the coefficient of variation of the nozzle distribution, the volume median diameter, the number median diameter, the homogeneity coefficient, and the percentage of droplets smaller than 100 mm. In a general way, the nozzles presented satisfactory levels of distribution uniformity, working with a pressure of 300 kPa and 50 cm of height. The appraised nozzles, in agreement with the used methodology, presented a volume mode diameter of 340 mm, and the droplets spectrum was shown to be within the recommended patterns. The homogeneity coefficient of the droplet size was better with low flow and low pressure.

Deposição e uniformidade de distribuição da calda de aplicação em plantas de café utilizando a pulverização eletrostática

In the scope of the application technology of pesticides, electrostatic spraying is a system commercially available, however, little used because there is some disagreement as to the efficiency of this system, so understanding this technology and its interactions with the plant become necessary. In this context, the aim of this study was to evaluate the electrostatic spraying on coffee as to the deposition efficiency and distribution uniformity of spray. We used an electrostatic sprayer, manufactured by Electrostatic Spraying Systems Co., model ESS MBP 4.0. The experiment was set on split plot design, (2x3x6), with two spraying systems (electrostatic system on and off), three parts of the plant (top, medium and bottom) and six positions of leaves collection, with four replications. As for the distribution uniformity of spray, it was observed there was more variability in the deposition when the electrostatic system remained on, with higher deposition in the outer canopy. The coefficients of variation for the electrostatic system on and off were 40.3 and 33.08%, respectively. The electrostatic spraying system was effective in coffee plants and increased spray deposition of 37% compared to when the electrostatic system was off.

Correlação linear e espacial entre produtividade de Brachiaria brizantha, densidade do solo e porosidade total em função do sistema de manejo do solo

Total porosity and bulk density are strongly affected by soil management, which reflects directly in agricultural productivity. The productivity of the forage, Brachiaria brizantha, in function of bulk density and total porosity was analyzed in two soil management systems, in an experiment lead in the second semester of 2009, in Santa Teresa County, state of Espirito Santo, Brazil. The purpose of the study was to evaluate the variability, and linear and spatial correlations among the attributes (plant and soil) in order to identify an indicator of soil physical quality for corn forage productivity. A geostatistical grid was installed to collect soil and plant data, with 99 sample points, in each soil management system. The studied attributes did not vary randomly and the variability was medium to low, with well defined patterns. The spatial range varied between 20.3 and 24.2 m. On the other hand, the linear correlations between the forage productivity with the soil attributes were low due to the high data number. The comments of better correlation for productivity, was the bulk density in the depth of 0.0 - 0.15 independently of the soil management system, indicating that the productivity and the density of the soil are inversely proportional. Thus, the bulk density in the 0.0 - 0.15 m soil layer proved to be a satisfactory index of the soil physical quality regarding to forage yield.

Estimativa de parâmetros técnicos da tecnologia de aplicação do glyphosate no controle de Brachiaria decumbens

Estimate of technical parameters of glyphosate application technology in the control of Brachiaria decumbens The interaction between the volumetric median diameter (VMD), density (DEN) and coverage (COV) provided by spray droplets is scarcely studied and may influence the application of herbicides in general. This study aimed to estimate the technical parameters of the glyphosate application technology in the control of Brachiaria decumbens Stapf. The treatments consisted of the combination of five rotational speeds of a centrifugal sprayer (105, 157, 210, 262, 315 rad s -1 ) with six travel speeds (0.5; 1.0; 1.5; 3.0; 4.5 and 6.0 km h -1 ).The tests were performed in the laboratory, and the sprayer was adapted into a bar equipped with an electric engine and a control unit to control the travel speed. Visual analyses were carried out and percentage of reduction in plant dry biomass was compared with the control without

Eficácia do fungicida epoxiconazol aplicado via pivô central no feijoeiro

The fungigation of bean crops have been used in Brazil by the agriculturists since the beginning of the 1980s. However, few surveys have been conducted to evaluate the efficiency of this technique. Thus, the objectives of this work were to evaluate the efficacy of the fungicide epoxiconazol, applied through irrigation water, for the control of diseases in bean crops, under conventional and no-till systems; as well as to study the influence of depth of applied water on the fungigation efficiency. The fungicide epoxiconazol was applied on the bean crops, under conventional and no-till systems, by a center pivot system with different depths of applied water (3, 5 and 7 mm), and disease severity was evaluated for each test. The efficiency of the fungicide application by a conventional system (compression knapsack sprayer) was also evaluated. The results obtained allow us to affirm that the fungicide epoxiconazol, applied by a center pivot system, decreased the severity of bean angular leaf spot and bean alternaria leaf spot; and the depth of applied water by fungigation did not influence the efficacy of the fungicide epoxiconazol.

CARACTERIZAÇÃO DAS VIBRAÇÕES MECÂNICAS NO E RUÍDO NO POSTO DE OPERAÇAO NO TRATOR AGRÍCOLA MODIFICADO “TRANSFORMAX”

The ergonomic studies aimed at adapting the work to man, through the task analysis, posture and worker movements, as well as their physical and psychological requirements, in order to reduce fatigue and stress, providing a comfortable job and safe. One of the undesirable factors occurring in agricultural tractors is vibration, not only because the produced discomfort, and possible degradation of the operator’s health, but also because of the increased dynamic stresses that can lead to fatigue and failure of the tractor elements. Already excessive noise can cause decrease or loss of hearing ability when the exposure time is too long. Thus, this study aims to assess the levels of noise and vibration in the agricultural tractor operator station Transformax® modified, depending on the traction force and rotation of the drive shaft, with types of rotated, of width 13.6 and 18.4. For this experiment was performed a frequency spectrum analysis for all treatments in order to verify the behavior of the vertical and longitudinal vibrations at the base of the operator station, according to each frequency band and the noise levels were determined with the aid of a digital noise , positioned near the operator’s ear. The variables, traction force and rotation of the drive shaft showed no significant effect on noise levels in tractor operator station, however, the average noise levels were higher in the tractor equipped with tires 18.4.