Engenharia Agrícola
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/10363
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Resultados da Pesquisa
Item 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.Item Price and quality of coffee (Coffea arabica L.) dried using air dehumidified by convection(Associação Brasileira de Engenharia Agrícola, 2019) Konopatzki, Evandro A.; Christ, Divair; Coelho, Silvia R. M.; Demito, Angélica; Werncke, Ivan; Camicia, Rafaela G. da M.Grain drying processes have been improved to reduce costs and losses of coffee beverage quality. The objectives of this study were to evaluate the quality of coffee dried using air partially dehumidified before entering drying units (DUs) in four coffee-producing farms, as well as the effects of such process on coffee commercial value. The method consisted of obtaining three samples (triplicates) of coffee dried in both DUs and concrete terraces (control) for mean multiple comparisons. The following variables were analyzed for sieve #13 and hand-picked beans: defect number, cupping test, and pricing. Evaluations were carried out by three professional graders. The results showed that coffee dried in the DUs presented fewer broken grains, higher cupping score, and less negative factors of handsorting and defects. As a conclusion, it should be emphasized an average increase of 12.11% in price for coffee beans previously dehumidified.Item Mathematical modelling and immediate and latent quality of natural immature coffee under different drying conditions(Associação Brasileira de Engenharia Agrícola, 2019) Andrade, Ednilton T. de; Lemos, Isabella A.; Dias, Camila de A.; Rios, Paula de A.; Borém, Flávio M.This work aimed to study the immediate and latent effects of different relative humidities on the quality of dried coffee fruits, describe the drying kinetics of natural immature coffee (Coffea arabica L.), and evaluate the mathematical model that best fits the experimental drying data. The drying was carried out in a fixed layer dryer coupled to a composite air conditioning system in which the drying air was controlled with an air flow of 20 m3.min1.m-2, at a temperature of 40 °C, and at relative humidities of 10%, 17.5% and 32.5%. Manually harvested coffee fruits were used and dried to a mean water content of 0.120 dry basis (d.b). After drying, the kinetic curve and the physical and physiological properties were determined. The coffee was stored in permeable packs for 6 months. The electrical conductivity, potassium leaching, and colour analysis were performed every 2 months. For the modelling adjustment, the models were tested, and the Midilli model had the best fit with the drying kinetics of the immature coffee. No immediate damage was observed in the physical and physiological quality of the coffees, and latent damage was perceived after 120 days of storage for the natural immature coffees.Item Spray retention on coffee leaves associated with type and concentration of adjuvants(Associação Brasileira de Engenharia Agrícola, 2019) Cação, José E. da C. R.; Moreira, Bruno R. de A.; Raetano, Carlos G.; Carvalho, Fernando K.; Prado, Evandro P.Agricultural spray adjuvants (ASA) are widely used in pesticide applications to enhance the performance of pesticides. The aim of this research was to investigate the effects of ASA on static surface tension (SST) and foliar spray retention on coffee leaves. The SST of ASA at different concentrations was determined by the drop weight method. Spray retention on adaxial and abaxial coffee leaf surfaces was performed using a micro-sprayer at solution concentrations of 0, 0.01, 0.1, 0.5, and 1.0% v v-1. The ASA assessed were: polyether-polymethylsiloxane-copolymer (PPC); Nonylphenol ethoxylate; nonyl polyethylene glycol ether; mineral oil; nonylphenoxy polyethoxy ethanol; carboxyl copolymer of styrene and butadiene; primary aliphatic oxyalkylated alcohol plus carboxyl copolymer of styrene and butadiene; and soyal phospholipids and propionic acid. All ASA reduced the SST of the aqueous solutions. PPC provided the best performance in decreasing SST, reaching values below 20 mN m-1 at a concentration of 0.05% v v-1. Spray retention on leaves was influenced by adjuvant type as well as concentration. A very strong positive correlation between SST and spray retention on coffee leaves was observed. Decreasing the SST of the solution provided a reduction of spray retention when spraying was performed until run-off point.Item Parameters of operational performance of soil preparation and semi-mechanized transplantation of coffee seedling(Associação Brasileira de Engenharia Agrícola, 2018-11) Cunha, João P. B.; Silva, Fabio M. da; Andrade, Ednilton T.; Barros, Murilo M. deIn recent years, the coffee has undergone major changes, and in case of transplanting operation, the use of machinery has proved to be a viable alternative to producers. Prior knowledge of the influence of the variables that influence the operational capability of these machines can generate models to estimate precisely these parameters, thus enabling the optimization and management of mechanized operations. One of this tool is the use of the response surface methodology, which allows checking the influence of different independent variables and the response generated to allow a great value. This study aims to verify the use of the response surface method to determine parameters of mechanized operations in coffee plant implantation. The results show that the number of seedlings deposited increases with the increase in operating speed. In contrast, the adoption of higher speeds decreases the efficiency of the evaluated field operations. The response surface methodology was an important tool to check the effect of variables on performance parameters, and the generated models showed high significance allowing the identification of the effects of the operational speed and the average length of the cultivation line.Item Sampling density for characterizing the physical quality of a soil under coffee cultivation in southwestern Minas Gerais(Associação Brasileira de Engenharia Agrícola, 2018-09) Silvero, Nélida E. Q.; Marques Júnior, José; Siqueira, Diego S.; Gomes, Romário P.; Costa, Milene M. R.The elaboration of maps to characterize the spatial variability of soil attributes assists in the strategic planning and decision making of agricultural managers. Precision and accuracy of maps are related to the ideal sampling density to characterize the variability pattern. This study was conducted with the aim of identifying the sampling density to represent the variability of soil physical quality using attributes with different magnitudes of variation in an area cultivated with coffee. Three approaches were used to find the most adequate sampling density (geostatistical analysis, percentage of error associated with the sampling density, and coefficient of variation). A total of 145 soil samples were collected at a depth of 0–0.20 m at the crossing points of a regular grid with a spacing of 50 m. The percentage of clay, silt, and sand, macroporosity, microporosity, total pore volume, and soil density were determined. The data were submitted to descriptive statistical analysis. For elaborating the variability maps with up to 15% error and soil attributes with a coefficient of variation close to 50%, a sampling density of 3 points ha−1 is suggested.Item Physiological responses of coffee tree under different irrigation levels(Associação Brasileira de Engenharia Agrícola, 2018-09) Costa, Jéfferson de O.; Coelho, Rubens D.; Barros, Timóteo H. da S.; Fraga Júnior, Eusímio F.; Fernandes, André L. T.The plant water potential and the leaf temperature are physiological responses of the coffee tree that can be used as indicative of the irrigation management of this crop. There is a dependence between the leaf water potential with the potential matrix of the soil solution, however, the water potential levels found for the coffee tree show divergent relationships in the literature regarding the matrix potential. The objective of this study is to verify the water potential and leaf surface temperature in the coffee tree when submitted to different irrigation levels. The study was conducted in Piracicaba, SP, Brazil, using Coffea arabica species from Red Catuaí IAC 144 variety, the drip irrigation system was adopted and the management done by tensiometry. The relationships among these physiological responses and the treatments of actions presented high determination coefficients (R2 of 0.84, 0.90 and 0.65 for the leaf water potential, leaf temperature measured with the portable infrared sensor and the thermal camera respectively). The estimated values for leaf water potential were -0.23, -0.56, -0.89 and -1.22 MPa for irrigation treatments L130%, L100%, L70% and L40%, respectively. The calculated leaf temperature values were 31.7, 32.4, 33.0 and 33.7°C in average, for treatments L130%, L100%, L70% and L40% in proper order.Item Geotecnologias para mapear lavouras de café nos estados de Minas Gerais e São Paulo(Associação Brasileira de Engenharia Agrícola, 2010-11) Moreira, Mauricio A.; Rudorff, Bernardo F. T.; Barros, Marco A.; Faria, Viviane G. C. de; Adami, MarcoO uso operacional de imagens de satélites de sensoriamento remoto para mapear lavouras de café em grandes áreas, para fins de obtenção de estatísticas agrícolas confiáveis e oportunas, ainda se encontra em desenvolvimento. Diversos são os fatores que dificultam a correta identificação e mapeamento do parque cafeeiro. Contudo, os avanços tecnológicos observados nos últimos anos em termos de aquisição de imagens com melhor qualidade e em maior quantidade, bem como o desenvolvimento de novas ferramentas de análise, propiciam o desenvolvimento de um método operacional que pode contribuir na formação das estatísticas agrícolas oficiais do café no Brasil. Neste sentido, o presente trabalho tem por objetivo relatar a metodologia e apresentar os resultados do mapeamento das áreas cultivadas com café nos Estados de Minas Gerais e São Paulo, utilizando imagens de sensoriamento remoto e técnicas de geoprocessamento. A abordagem metodológica consiste em quatro fases: a) restauração das imagens e georreferenciamento; b) classificação não supervisionada; c) interpretação visual na tela do computador para minimizar erros de omissão e inclusão, e d) determinação da área cultivada com café. Os resultados indicaram que a metodologia utilizada foi adequada para o mapeamento das lavouras de café de Minas Gerais e São Paulo.Item Manejo e viabilidade econômica da irrigação por gotejamento na cultura do cafeeiro acaiá considerando seis safras(Associação Brasileira de Engenharia Agrícola, 2010-09) Oliveira, Ednaldo L. de; Faria, Manoel A. de; Reis, Ricardo P.; Silva, Mirian de L. O. eEste trabalho teve como objetivo estudar técnica e economicamente o efeito da irrigação por gotejamento na produção do cafeeiro (Coffea arabica L.) Acaiá MG-1474. O delineamento experimental utilizado foi o de blocos casualizados, com cinco tratamentos e quatro repetições. Os tratamentos foram: L 0 = sem irrigação; L 40 = 40%; L 60 = 60%; L 80 = 80% e L 100 = 100% da Evaporação do Tanque Classe A (ECA). Para realizar a análise econômica, utilizou-se dos dados de produção acumulada das seis primeiras safras: 1999, 2000, 2001, 2002, 2003 e 2004. A análise dos custos da lavoura irrigada foi baseada na teoria dos custos de produção. A produtividade média dos tratamentos foi de 52,88; 66,99; 70,00; 71,93 e 79,50 sacas por hectare, para L 0 , L 40 , L 60 , L 80 e L 100 , respectivamente. Considerando o preço da saca de café a R$ 212,00, a situação econômica analisada mostrou que, neste nível de preço, é economicamente viável a produção de café, quer seja irrigado, quer não, sendo que, para os tratamentos irrigados, o manejo da irrigação, com a lâmina de reposição de 100% da Evaporação do Tanque Classe A, proporcionou maiores lucros.Item Estimativa de parâmetros biofísicos de plantios de café a partir de imagens orbitais de alta resolução espacial(Associação Brasileira de Engenharia Agrícola, 2010-05) Ramirez, Gláucia M.; Zullo Júnior, JurandirESTIMATION OF BIOPHYSICAL PARAMETERS OF COFFEE FIELDS BASED ON HIGH-RESOLUTION SATELLITE IMAGESO uso de recursos de sensoriamento remoto orbital constitui um grande avanço no levantamento de dados sobre a cafeicultura, sobretudo por seu caráter temporal e baixo custo. Sendo assim, o objetivo do trabalho foi avaliar a utilização da imagem do satélite QUICKBIRD na determinação de parâmetros biofísicos importantes para a cultura cafeeira. Foram utilizados 25 talhões com plantios de café localizados entre os municípios de Ribeirão Corrente, Franca e Cristais Paulista (SP). Os parâmetros biofísicos utilizados foram os espaçamentos entre linhas e plantas, altura, IAF, diâmetro da copa, porcentagem de cobertura vegetal, rugosidade, variedade e biomassa. Foram utilizados valores de refletância real das bandas espectrais do satélite QUICKBIRD e os índices de vegetação NDVI, GVI, SAVI e RVI. A partir desses dados, foram feitas análises de regressão linear e não linear para a geração dos modelos de estimativa. A utilização de modelos de regressão baseados em equações não lineares mostrou-se mais adequado para determinar os parâmetros IAF e a porcentagem de biomassa, importantes como indicativos da produtividade da cultura cafeeira.