Navegando por Autor "Cunha, João P. A. R. da"

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Deposição de calda em folhas de cafeeiro e perdas para o solo com diferentes taxas de aplicação e pontas de pulverização
(Departamento de Engenharia Agrícola - UFCG, 2014-12) Silva, João E. R.; Cunha, João P. A. R. da; Nomelini, Quintiliano S. S.
O cafeeiro apresenta diversos desafios para a tecnologia de aplicação dos produtos fitossanitários, principalmente no que se refere à penetração da calda no dossel da cultura e à redução da deriva. Objetivou-se analisar a deposição de calda pulverizada na folhagem do cafeeiro e a perda para o solo, proporcionada pela aplicação com diferentes taxas e pontas de pulverização. O experimento foi conduzido no esquema fatorial 2 x 2 e oito repetições, sendo os fatores pontas de pulverização (jato cônico vazio - ATR e jato cônico vazio com indução de ar - TVI) e taxas de aplicação de calda (200 e 500 L ha -1 ). Em todos os tratamentos as aplicações foram realizadas utilizando-se um pulverizador hidropneumático e o marcador Azul Brilhante, o qual foi quantificado por espectrofotometria. Para avaliação de depósito foram coletadas folhas das metades superior e inferior das plantas e também lâminas de vidro já posicionadas junto à superfície do solo. O uso de pontas com indução de ar mostrou-se viável quanto à deposição de calda no cafeeiro, principalmente junto ao uso da maior taxa de aplicação. O emprego da menor taxa (200 L ha -1 ) mostrou-se viável junto ao uso da ponta de jato cônico vazio. A ponta com indução de ar proporcionou maiores perdas para o solo.
Estimating vegetation volume of coffee crops using images from unmanned aerial vehicles
(Associação Brasileira de Engenharia Agrícola, 2019) Cunha, João P. A. R. da; Sirqueira Neto, Matheus A.; Hurtado, Sandro M. C.
Tree crops, such as Arabica coffee (Coffea arabica L.), present enormous technical challenges in terms of pesticide application. The correct deposition and distribution of the active ingredient throughout the aerial part of these plants depends on knowledge of the canopy volume, but manually determining this volume is time consuming and imprecise. The objectives of this study were to develop a method to determine the vegetation volume of coffee crops from digital images captured by camera onboard unmanned aerial vehicles and to compare this approach with traditional vegetation volume estimation (tree row volume (TRV) method). Manual measurements of the canopy volume of four coffee cultivation areas were compared with data obtained using the method presented in this paper. It was concluded that the vegetation volume of coffee trees, a highly important variable in defining pesticide application techniques (in addition to other uses), could be determined in a practical and precise way by digitally processing the images captured by unmanned aerial vehicles. The method is fast and permits the assessment of large areas. Furthermore, estimates based on this method and the traditional TRV method were not significantly different.
Mobile Application for Adjusting Air-Bast Sprayers in Coffee Plantation
(Associação Brasileira de Engenharia Agrícola, 2022-09-13) Cunha, João P. A. R. da; Alves, Thales C.; Penha, Rafael S. A.
Mobile application development advances, particularly for smartphones and tablets, have allowed farmers to make decisions more assertively in their agrobusiness management. This article addresses the development and evaluation of an app aimed at people who deal with the pesticide application technology in coffee farming, more specifically, adjustment and calibration of sprayers. This mobile app provides the main data necessary for a correct calibration of air-blast sprayers to apply pesticides in coffee planting. Its functionalities include calculation of the application rate for each situation (L ha-1) based on data obtained in the field, such as canopy volume. The app, called SprayCafé, was developed for the Android platform using the Java programming language in the integrated development environment Android Studio. After the development, the application was evaluated, based on a questionnaire answered by 139 users, who ranked the following requirements: ease of use, loading time, adequacy of screen resolution, data relevance, sequence of information, and applicability, among others. The system proved to be simple and robust; it was thus assessed as adequate to the field and to be of great value for coffee planting, especially because it allows safer and more adequate pesticide application. The graphical user interface is interactive and easy to use.
Mobile application for adjusting air-blast sprayers in coffee plantation
(Associação Brasileira de Engenharia Agrícola, 2022-09-13) Cunha, João P. A. R. da; Alves, Thales C.; Penha, Rafael S. A.
Mobile application development advances, particularly for smartphones and tablets, have allowed farmers to make decisions more assertively in their agrobusiness management. This article addresses the development and evaluation of an app aimed at people who deal with the pesticide application technology in coffee farming, more specifically, adjustment and calibration of sprayers. This mobile app provides the main data necessary for a correct calibration of air-blast sprayers to apply pesticides in coffee planting. Its functionalities include calculation of the application rate for each situation (L ha-1) based on data obtained in the field, such as canopy volume. The app, called SprayCafé, was developed for the Android platform using the Java programming language in the integrated development environment Android Studio. After the development, the application was evaluated, based on a questionnaire answered by 139 users, who ranked the following requirements: ease of use, loading time, adequacy of screen resolution, data relevance, sequence of information, and applicability, among others. The system proved to be simple and robust; it was thus assessed as adequate to the field and to be of great value for coffee planting, especially because it allows safer and more adequate pesticide application. The graphical user interface is interactive and easy to use.
Multivariate analysis applied to spray deposition in ground application of phytosanitary products in coffee plants
(Associação Brasileira de Engenharia Agrícola, 2021) Palma, Roxanna P.; Cunha, João P. A. R. da; Guimarães, Ednaldo C.; Santana, Denise G. de; Assunção, Heli H. T. de
An adequate combination of factors involved in the technology used for phytosanitary product application contributes to an efficient spray deposition on the target. The objective of this study was to use multivariate analysis to characterize the magnitude of effects and the order of influence of three factors that interfere with the quality of phytosanitary product application in coffee plants. An entirely randomized design was adopted, with four repetitions, using a 2 × 2 × 3 factorial scheme, with two classes of droplets quality (fine and coarse), two application rates (250 and 400 L ha-1), and the use of adjuvants (with no adjuvant or with Fighter® and Aureo® adjuvants). The quality of the application was determined by jointly analyzing the spray deposition on three thirds of leaves, in their internal and external layers, the runoff to soil, coverage, droplet density, relative amplitude, and the volumetric median diameter. The results underwent analysis of variance (ANOVA) to measure the effect sizes (η2). After testing the assumptions of multivariate analysis, clustering and principal component analyses were performed. The class of droplets was found to be the most influential factor in the quality of the phytosanitary product application (spray deposition and runoff to soil). When focusing on spray deposition on leaves, the second-most influential factor was the application rate and the relation between the application rate and the adjuvants. For the other variables, the second-most influential factor was the application rate.
Spray deposition and chemical control of the coffee leaf-miner with different spray nozzles and auxiliary boom
(Associação Brasileira de Engenharia Agrícola, 2016-07) Gitirana Neto, Jefferson; Cunha, João P. A. R. da
The coffee crop requires great spray ability to penetrate into the plant canopy during the application of pesticides. The aim of this study was to evaluate the spray deposition on leaves of coffee plants and the chemical control of the leaf miner provided by the application of different spray nozzles, with and without the use of an auxiliary boom. The deposition on the upper, middle and lower parts of the plants and the losses to the soil were evaluated using a tracer quantified by spectrophotometer. We also evaluated the chemical control of the leaf miner, counting the larvae, after the application of the insecticides cartap and fenpropathrin. The trial was carried out in a randomized block design, with four replications, in a factorial model (2×2+1): with and without the auxiliary boom, three spray nozzles (hollow cone – MAG 02, flat fan – AD 11002 and air induction hollow cone – TVI 8002) and a control. The use of the auxiliary boom increased the deposit ion in the lower part of the plants but decreased in the middle part, besides the increase in the runoff. The different nozzles do not provided differences in the deposition, showing the technical feasibility in the use of the hollow cone nozzles with coarse droplets and flat fan. All the chemical control decreased the leaf miner population, without differentiation.