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Maceió, Brazil

de Albuquerque A.W.,CECA UFAL | dos Santos J.M.,Instituto Federal Of Alagoas | de Farias A.P.,Instituto Federal Of Alagoas
Revista Brasileira de Engenharia Agricola e Ambiental

The silicon fertilization can increase productivity by increasing resistance to lodgaing, to water stress and dehydration after harvest. The objective of this study was to evaluate productivity and postharvest quality of Heliconia Golden Torch under doses and sources of silicon. The experiment was conducted in randomized design in factorial 3 × 4 with four replications, utilizing three sources and four doses of silicon. The following variables were evaluated: number of tillers, the beginning of the flowering, length of flower stem, diameter of flower stem, length of bract, number of flower stem, silicon content in leaves and burning of bracts on the 5th, 10th and 15th day postharvest. The results showed that the application of sodium silicate was better to influence the growth of Heliconia Golden Torch. The higher doses of sodium silicate which influenced the length of flower stem, diameter of flower stem, length of bract and the number of the flower stem were 576, 400 and 560 mg dm-3. The burning of bract was less when sodium silicate was applied at dose of 550 mg dm-3. Content of silicon in the leaf increased with increasing doses of application of calcium silicate. Source

Goncalves E.R.,CECA UFAL | Souza F.C.,CECA UFAL | dos Santos L.N.,CECA UFAL | Silva J.V.,UFAL | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental

Tabebuia aurea (Benth. & Hook. f. ex S. Moore) (Bignoniaceae) is a boreal species common in Brazil. It is used for ornamental parks and along sidewalks. Its timber is also used for furniture. The objective of this study was to evaluate the effect of nursery shading on the growth and photosynthesis of T. aurea and their photosynthetic adaptation after being transferred to direct sunlight. The T. aurea seedlings were grown under 0, 50, 70 or 95% shade. The photosynthetic active radiation and leaf gas exchange were measured over two distinct periods: 51 (young seedlings) and 70 days after having been sown under each shade treatment. Immediately after the measurements were taken, the seedlings were transferred into full sunlight and the measurements were repeated two times after 15 min and 3 days under ambient sunlight. T. aurea seedlings showed satisfactory growth up to 50% shade in the nursery, which could be verified both by growth measurement and by total biomass accumulation. Shading greater than 70% reduced the number of leaves, the leaf area and the stem diameter in relation to plants exposed to full sunlight. The results suggest that T. aurea seedlings should be grown under full sunlight or under shading up to 50% to maximize their growth in the nursery and to minimize stress when transferring the seedlings to their final planting sites. Source

Ferreira Junior R.A.,CECA UFAL | de Souza J.L.,ICAT UFAL | Lyra G.B.,IF DCA UFRRJ | Teodoro I.,CECA UFAL | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental

Sugarcane growth can be obtained by biophysical models in which gross photosynthesis (GP) is obtained as a function of solar radiation. This work aims to evaluate sugarcane varieties under irrigation in relation to intercepted photosynthetic active radiation (PARint) and the estimated accumulative GP. To achieve that, a study was conducted at the Federal University of Alagoas during 2008 and 2009, with RB sugarcane varieties. Biometric measurements, production variables and meteorological elements were made. The intercepted photosynthetic irradiance (PAR) was obtained by the difference between PAR and transmitted PAR (PART), which was determined by Beer's Law. The daily GP was estimated numerically by the trapezoidal approach. The production variables had correlations with accumulated PARint and accumulated GP during the crop cycle. The average global solar radiation in the region for rainy season (May-August) was 14.9 MJ m-2. The variety RB92579 had the highest production variables as well as higher intercepted PAR and accumulated GP in the cycle due to its greater capacity for regrowth and energy conversion in photoassimilate. Source

Reis L.S.,CECA UFAL | de Souza J.L.,ICAT UFAL | de Azevedo C.A.V.,Bairro Universitario | Lyra G.B.,IF DCA UFRRJ | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental

The objective of this paper was to evaluate of net radiation, photosynthetic and solar irradiation in greenhouse conditions cultivated with tomato crop and its relationship with the global solar irradiation of the external environment. The tomato was cultivated in greenhouse (not acclimatized), with covering of polyethylene 0.12 mm of thickness. The global solar irradiation (Rgi), the net radiation (Rni) and the flux density of photosynthetic photons were obtained by radiometers connected to a datalogger installed into the protected environment. The external data (global solar irradiation, Rg) were collected in the Agrometeorological Station of the Agricultural Science Center of Federal University of Alagoas. The protecting environment promoted reduction in the solar irradiation, expressed as the transmittance of the polyethylene in 62%. The relationships between the components of radiation from internal and external environment were expressed satisfactorily by linear regressions, with coefficients of determination (R2) greater than 0.88, while for the photosynthetic irradiation (PARi) the R2 were higher than 0.52. The obtained relationships showed that Rni is 0.60 of the Rgi and the PARi is proportional to 0.28 of the Rg and 0.44 of the Rgi. The mean albedo of crop over the cycle was 0.15. Source

Ferreira Junior R.A.,CECA UFAL | de Souza J.L.,ICAT UFAL | Escobedo J.F.,Sao Paulo State University | Teodoro I.,CECA UFAL | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental

The management of drip irrigation and mechanized harvesting in the sugarcane crop are suggesting combined row plants per square meter spacing. In this context the objective of this study was to evaluate the growth of RB98710 variety, with drip irrigation degree days in two row spacing. For this, two plantings were performed in August 2011, with single (1.0 m) and combined row spacing (0.6 and 1.4 m). Te analyzed data were variables of plant growth (leaf area index, canopy height, length of stems and plants per square meter), production variables and weather elements. Te form factor value for leaf area was equal to 0.65. In both row spacing, the variables of plant growth were related with accumulated degree-days and had adjusted equations with satisfactory applications. Te evaluated variables of plant growth were not different by the used row spacing configurations. Te fresh stalk yield (100.9 t ha-1) and sugar yield (17.8 t ha-1) of irrigated sugarcane crop cultivated in Rio Largo, Alagoas state, Brazil, were not influenced by the use of different row spacing configurations. Source

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