The drift of hormonal effect herbicides is a major problem for agriculture, because, even in small amounts, it may cause high losses in crops with plants that are sensitive to their action mechanism. This study aimed to evaluate the efficiency of hydraulic spray nozzles with air induction, as well as the use of the LI-700 adjuvant, in the reduction of the 2,4-D herbicide drift, in tomato crop. A complete randomized split-plot experimental design, with eight replications, was used. Two herbicide solutions were assigned in the plots (with or without the use of adjuvant) [2,4-D (670 g ha-1) and 2,4-D (670 g ha-1) + LI-700 (712.88 g ha-1)], and, in the subplots, five nozzle models [simple fan (JSF11003), simple fan with air induction (AD-IA11003), dual fan with air induction (AD-IA/D11003), simple hammer fan with air induction (TTI11003-VP) and empty cone with air induction (CV-IA10003). The treatments were applied in a wind tunnel, under a pressure of 300 kPa. In a laser analyzer, applying only water, the volumetric median diameter, the relative amplitude and the percentage of drops with diameter lower than 150 µm were measured for all nozzle models. The CV-IA10003 and TTI11003-VP hydraulic nozzles outstand by reducing the 2,4-D herbicide drift and decreasing the damage to tomato plants. The addition of the LI-700 adjuvant to the 2,4-D syrup, independently of the nozzle model, reduces the drift of this herbicide and its effects on the tomato plant root. However, even when adopting these technologies, the application of the 2,4-D herbicide near the tomato crop should be avoided.
A aplicação foliar é usualmente utilizada em cultivos de soja visando o fornecimento de micronutrientes. A solubilidade das fontes de nutrientes e o uso de agentes quelantes podem influenciar a absorção e a translocação na planta e, por conseguinte, na resposta da soja à adubação foliar. Portanto, objetivou-se avaliar a aplicação foliar de doses e fontes de cobre e manganês nos teores foliares destes micronutrientes e na produtividade da soja. Foram conduzidos quatro experimentos, em duas áreas de cultivo, no ano agrícola 2015/16. Em cada área conduziram-se dois experimentos, sendo um referente a Cu e outro a Mn. Os experimentos foram em esquema fatorial (4 x 3) + 1, o primeiro fator foram as doses de Cu ou Mn e o segundo as fontes (sulfato, sulfato quelatizado com EDTA e óxido micronizado) e um adicional sem o uso destes micronutrientes. Observou resposta quadrática, positiva ou negativa, para as fontes que apresentaram diferença significativa entre doses. Houve aumento do teor foliar de Cu em função de doses em uma das áreas de cultivo, entretanto o mesmo não aconteceu para Mn. Na outra área de cultivo, as fontes óxido de Cu e sulfato de Mn proporcionaram maiores teores foliares destes nutrientes. As fontes e doses de Cu e Mn influenciaram seus respectivos teores foliares, porém não alteraram a produtividade da cultura da soja.
Spray distribution generated by axial fan sprayer, among other factors, should be critically analyzed, in order to prevent unnecessary costs and environmental contamination. This study aimed at evaluating the effect of the vertical volumetric distribution of an axial fan sprayer on the Brevipalpus phoenicis control efficiency. First, an assay was performed to evaluate the vertical volume distribution uniformity of the sprayer, assessing different spray nozzles configurations on the spray arcs, sides of the sprayer and spray heights. Afterwards, another experiment was carried out to analyze the relationship between the distribution of the Fenpyroximate acaricide on Coffea arabica L. and the B. phoenicis control efficiency. The treatments were arranged in a 4 x 2 factorial + 1 additional control, consisting of four spray volumes (200 L ha-1, 400 L ha-1, 600 L ha-1 and 800 L ha-1) and two spray nozzles configurations (1: 100 % of MAG1.5 nozzles; 2: upper extension with 5 MAG3.0 nozzles, middle extension with 9 MAG1.5 nozzles and lower extension with 4 MAG3.0 nozzles). Configuration 2 provided the smallest coefficient of variation (28 %). Nozzle configurations had no effect on the incidence of B. phoenicis. The use of nozzles with different flow rates on the spraying arc improves the vertical volumetric distribution uniformity of axial fan sprayers, but does not affect the B. phoenicis control efficiency.
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