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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Respuesta fotosintética de Coffea arabica L. a diferentes niveles de luz y disponibilidad hídrica(Universidad Nacional de Colombia, 2014) Mariño, Yesid AlejandroEl sombrío permite una mejor aclimatación del café (Coffea arabica L.) en zonas donde el invierno se caracteriza por bajas temperaturas nocturnas seguido de días soleados y el verano, por altas tempera turas y lluvias ocasionales. En este estudio, realizado en Viçosa-MG, Brasil, se analizaron los efectos de dos condiciones de luminosidad (pleno sol y 15% de la radiación solar) y disponibilidades de agua en el suelo sobre las relaciones hídricas y el desempeño fotosintético en C. arabica en dos épocas con trastantes. Independientemente de la época de evaluación, las plantas cultivadas en condiciones de baja disponibilidad hídrica presentaron reducciones en la fotosíntesis (A), conductancia estomática (gs) y en la razón Ci/Ca en los dos tratamientos lumínicos. Estos cambios fueron acompañados con la reducción en la conductancia hidráulica y la transpiración. No se presentaron diferencias significativas en la producción cuántica efectiva, en el coeficiente de extinción no-fotoquímica y en la productividad cuántica basal de los procesos no fotoquímicos. Sobre la disponibilidad hídrica adecuada, las plantas cultivadas al sol presentaron reducciones en A, gs y Ci/Ca en la época de invierno. Adicionalmente, se encontraron limitaciones fotoquímicas con la reducción en la razón de las fluorescencias variable e inicial. Los resultados indican que cualquier recomendación de uso de sombrío como práctica de manejo debe ser tomada con precaución.Item Soil attributes and coffee yield in an agroforestry system(Editora UFLA, 2020) Jácome, Máximo Gerardo Ochoa; Mantovani, José Ricardo; Silva, Adriano Bortolotti da; Rezende, Tiago Teruel; Landgraf, Paulo Roberto CôrreaCoffee growing in an agroforestry system may provide improvements in soil chemical and physical attributes, increase crop yield and diversify production. However, there are few studies on coffee growing intercropped with high quality wood-producing species such as African mahogany, teak and Australian cedar. The objective of this study was to evaluate, in an agroforestry system, the effect of coffee intercropping with tree species and the density of these species on chemical and physical soil attributes and on coffee yield. The experiment was carried out in Santo Antônio do Amparo, MG, and Catuaí Vermelho IAC 99 coffee was used in a 3.4x0.7m spacing. A randomized block design with split plots was used, with one additional treatment and 4 replications. The treatments consisted, in the plot, of three tree forest species: Australian cedar, teak and African mahogany, used intercropped with coffee; and, in the subplots, two densities of these forest species: 82 plants ha-1 (13.6 m between rows and 9 m between plants) and 41 plants ha-1 (13.6 m between rows and 18 m between plants). The additional treatment consisted of conventional coffee cultivation growing without intercropping with the tree species. At 64 months after the experiment was set, when the forest species were still under development, soil samples were taken at a depth of 0 to 0.1 m to determine the following chemical attributes: pH in H2O, potential acidity, organic matter content, P-Mehlich, K+, Ca2+, Mg2+, S, B, Cu, Fe, Mn, Zn and base saturation (V%); and physical soil attributes: bulk density, macroporosity, microporosity, total porosity. Soil temperature at 0.05 m depth and coffee yield were also evaluated. Chemical and physical attributes, besides soil temperature, are similarly influenced with the cultivation of Australian cedar, teak and African mahogany, intercropped with coffee, in both densities, 82 and 41 plants ha-1, after 5 years of implementation of the agroforestry system. Coffee cultivation in agroforestry system with Australian cedar, teak and African mahogany increases the organic matter and P content of the soil, but acidifies the soil and does not influence its physical attributes. The agroforestry system with teak and African mahogany increases coffee yield.Item Modifications on leaf anatomy of Coffea arabica caused by shade of pigeonpea (Cajanus cajan)(Instituto de Tecnologia do Paraná - Tecpar, 2004-11) Morais, Heverly; Medri, Moacyr Eurípedes; Marur, Celso Jamil; Caramori, Paulo Henrique; Ribeiro, Ana Maria de Arruda; Gomes, José CarlosModifications on leaf anatomy in Coffea arabica shaded with pigeonpea (Cajanus cajan), compared to cultivation under full sun, were assessed. The leaves fully exposed to sunlight presented thicker cuticles and cellular walls, narrower epidermis cells, palisade parenchyma with longer cells, thicker lacunar parenchyma, fewer intercellular spaces and a larger stomata number. Leaves under dense shade presented a narrower cuticle and cellular wall; a mesophyll with smaller volume, but with larger intercellular spaces; and epidermis with thicker cells and a smaller stomata amount, surrounded by subsidiary cells of smaller dimensions. Plants grown under full sunlight presented higher values of net photosynthesis. The results evidenced that the species C. arabica has a wide range of phenotypic adaptation to changes in the radiation intensity.