Crescimento de eucalipto em idade jovem e movimentação de cálcio e magnésio no solo em resposta à aplicação de calcário e gesso agrícola

• Ano de defesa: 2013
• Autor(a) principal: Rodrigues, Fernando Antonio Vieira
• Orientador(a): Venegas, Victor Hugo Alvarez
• Banca de defesa: Fontes, Maurício Paulo Ferreira , Paiva, Haroldo Nogueira de , Martins, Lafayete Gonçalves Campelo
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Solos e Nutrição de Plantas
• Departamento: Fertilidade do solo e nutrição de plantas; Gênese, Morfologia e Classificação, Mineralogia, Química,
• País: BR
• Palavras-chave em Português: Gessagem; Calagem; Eucalyptus
• Palavras-chave em Inglês: Gypsum; Lime; Eucalyptus
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/1641

Eucalypt is tolerant forest specie to acids soil, i.e., it has good growth even in soils with high exchangeable and active acidity, therefore, being dispensable liming in order to correct soil acidity. On the other hand, to obtain productivity around 50 m3/ha/year, eucalypt accumulates large amount of Ca in the shoot, from planting to harvest (6-7 years old). The aim of this study was to evaluate the eucalypt s growth, at 18 months old, in response to limestone and gypsum application in Cerrado soil. The experiment was carried out in an Oxisol, medium texture with 20 % of clay. The factors studied were: limestone-L (without-sL and with-cL), location (strip-S and broadcast-B) and incorporation-I (without-sI and with-cI), plus four additional treatments (two with gypsum-G and two with reactive phosphate rock-RPR), arranged in a [(23 1) + 2 + 2] factorial scheme, in a randomized block design, with four replications. Thus treatments were: sLSsI, sLScI, sLBcI, cLSsI, cLScI cLBsI and cLBcI complete factorial, and the additional (cLB+cGS)sI, (cLB+cGB)sI, sLSsIcRFR and cLBsIcRFR. In the treatments of the factorial and the two with gypsum was used 200 kg/ha of MAP (monoamonium phosphate) and for the two remaining treatments 500 kg/ha of RFR. Both, MAP and RFR were applied in furrow subsoiling. The application of limestone was 3.0 t/ha, except for treatments with gypsum (1.0 t/ha) and either with RFR, which were applied 2.4 t/ha of limestone. After 18 months of implementation of experiment was measured at 1.30 m from the ground the DBH (diameter at breast height) of 52 plants per plot to obtain its average diameter. A average tree was cut down, measured its height and fresh weight of the components (leaf, branch and trunk). We got a composite sample of each individual component (leaf, branch, bark and wood) for determination of dry matter and nutrient concentration and content. On average tree was also performed root sampling with two different methods: spade and probe. For this purpose, we got two replications with each sampling method, being therefore 22 plants evaluated by each method. Soil samples were collected in the layers of 0-10, 10-20, 20-40 and 40-60 cm of depth with a probe (2.5 cm of Ø). Were collected 16 single samples from each soil depth to make one composite sample per plot, in the region of the strip of 35 cm on each side of the planting, avoiding the subsoiling furrow. Application of limestone plus gypsum increased trunk production in 96 % compared with no application of limestone, and 24 % compared with isolated application of 3.0 t/ha of limestone. Application of limestone plus gypsum, with gypsum applied in the strip, promoted greater increase on the production variables compared to gypsum the broadcast. In the absence of limestone, application in subsoiling furrow of the RFR compared to MAP, increased the production of trunk 26 %. Application of limestone plus gypsum compared with limestone alone, increases Ca and S concentrations and decreases of Mg, in the leaves from middle third of the crown. Application of limestone in the strip promoted better distribution of Ca and Mg in the soil profile, compared to broadcast. Application of 3.0 t/ha of limestone on the strip, with or without incorporation, promoted significant increases in Ca and Mg concentrations at least 60 cm soil depth. With application of this same dose in broadcast, the effects were restricted to a maximum of 20 cm of depth. Recovery rates extractor averaged 22 and 36 % for Ca and Mg, respectively. Plant recovery rates were from 2.5 to 7.5 % for Ca and from 3.2 to 7.9 % for Mg, up to 18 months old. Estimated demand of Ca and Mg for eucalypt for productivity of 46 m3/ha/year, at 84 months old, was 238 and 43 kg/ha, respectively, for the treatments with limestone plus gypsum. The density of fine roots of the row is 2-fold higher than space between rows. Application of limestone in broadcast promoted density increase of fine roots up to 40 cm of soil depth. However, strip application increased root density in the 40-60 cm layer. The combined application of limestone plus gypsum compared to limestone alone showed that gypsum increased the density of fine roots up to 40 cm soil depth. Gypsum application in strip increased the density of fine roots compared to its application in broadcast. In general, the results with the two sampling methods, spade and probe, showed that improvement chemical of soil promoted increases in the fine roots density in the soil profile, although not in the same extent and clarity as shoot responses. The use of the probe allows the sampling of a larger number of points per tree, making better to represent the spatial variability of root system.