405 resultados para Eucalyptus. eng
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The effects of municipal-treated wastewater on growth and gas exchange characteristics were studied in eucalyptus plants cultivated in a greenhouse under continuous sub irrigation with 70 % Long Ashton solution as a control, 100 % treated wastewater, and treated wastewater diluted 50 % with tap water. Irrigation with wastewater resulted in a reduction of total dry matter per plant and the shoot-to-root ratio and increased specific leaf mass, irrespective of the dilution. The gas exchange characteristics were adversely affected by the irrigation with wastewater, with photosynthetic rates been negatively affected. Total chlorophyll and carotenoids content were reduced in plants grown under treated wastewater. The results demonstrated that when the eucalyptus plants were grown under treated wastewater as the only source of mineral nutrients they were able to produce nearly 50 % of the dry matter produced by the plants grown under appropriate mineral nutrient supply, irrespective of the dilution. Therefore, the contribution of mineral nutrients and organic matter from the treated wastewater used as agricultural irrigation will be significant in lower the fertilizer rates without reducing dry matter production per plant.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Although many studies have shown that soil solution chemistry can be a reliable indicator of biogeochemical cycling in forest ecosystems, the effects of litter manipulations on the fluxes of dissolved elements in gravitational soil solutions have rarely been investigated. We estimated the fluxes of NH4-N, NO3-N, K, Ca, Mg, Na, Cl, dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) over the first two years after re-planting Eucalyptus trees in the coastal area of Congo. Two treatments were replicated in two blocks after clear-cutting 7-year-old stands: in treatment R, all the litter above the mineral soil was removed before planting, and in a double slash (DS) treatment, the amount of harvest residues was doubled. The soil solutions were sampled down to a depth of 4 m and the water fluxes were estimated using the Hydrus 1D model parameterized from soil moisture measurements in 4 plots. Isotopic and spectroscopic analytical techniques were used to assess the changes in dissolved organic matter (DOM) properties throughout the transfer in the soil. The first year after planting, the fluxes of NH4-N, K, Ca, Mg, Na, Cl and DOC in the topsoil of the DS treatment were 2-5 times higher than in R, which showed that litter was a major source of dissolved nutrients. Nutrient fluxes in gravitational solutions decreased sharply in the second year after planting, irrespective of the soil depth, as a result of intense nutrient uptake by Eucalyptus trees. Losses of dissolved nutrients were noticeably low in these Eucalyptus plantations despite a low cation exchange capacity, a coarse soil texture and large amounts of harvest residues left on-site at the clear cut in the DS treatment. All together, these results clarified the strong effect of litter manipulation observed on eucalypt growth in Congolese sandy soils. DOM fluxes, as well as changes in delta C-13, C:N and aromaticity of DOM throughout the soil profile showed that the organic compounds produced in the litter layer were mainly consumed by microorganisms or retained in the topsoil. Below a depth of 15 cm, most of the DOC and the DON originated from the first 2 cm of the soil and the exchanges between soil solutions and soil organic matter were low. (C) 2014 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Wood basic density (BD) is related to other wood characteristics and its determination is important in forest inventory, though BD must be differentiated from the apparent density (AD), which relates to the moisture content (MC) of wood. The aim of this study is to demonstrate a reliable conversion from BD to AD for any MC of Eucalyptus grandis wood based on two exponential and linear models that relate volumetric shrinkage to MC. To this end, wood specimens were submitted to drying and the volumetric shrinkage was determined as a function of MC. The two models proved to be efficient in the conversion of BD to AD and vice versa.
Production and Use of Heteroptera Predators for the Biological Control of Eucalyptus Pests in Brazil
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Forest plantations with Eucalyptus spp. (L'H,r) in Brazil are highly yielding. However, this activity is more and more threatened due to interactions with phytophagous insects, especially by exotic species, such as the red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae). This study aimed to evaluate the resistance in eucalyptus against the psyllid in oviposition and biological development assays, attempting to identify potential genotypes resistant to the pest for forest plantations. In addition, we tested the hypothesis of that concentration of total phenolics and lignin, and amount of epicuticular wax were associated with the expression of resistance. Results showed that there was variation in the levels of resistance among the genotypes assessed. Oviposition non-preference was observed on Eucalyptus citriodora (Hook) in free-choice and no-choice tests, and Clone FP10 was least preferred in the no-choice test. The genotypes E. citriodora and Clone FP6 provided 100 % nymphal mortality, and Clones FP7 and FP9 also affected negatively the G. brimblecombei development by lengthening the duration of the nymphal stage and reducing adult emergence. Clone FP6 had higher concentration of total phenolics and larger contact angle formed between the water droplet and leaf surface, which may be associated with thicker layer of epicuticular wax on the leaves, and one of the causes of high nymphal mortality. Thus, the use of the resistant genotypes of eucalyptus screened against G. brimblecombei is a promising and viable alternative for forest plantations infested with this pest.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)