Availability of copper and zinc as affected by soil acidity in Eucalyptus plantation

• Autor(a) principal: Florentino, Antonio Leite
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/11/11150/tde-11102021-084743/
• topic: Calagem; Espécies reativas de oxigênio; Fases do solo; Íons metálicos; Liming; Metallic ions; Produção de madeira; Reactive oxygen species; Reflorestamento; Reforestation; Soil phases; Wood production

Brazil is a global reference regarding Eucalyptus management for wood production (e.g., pulp and solid wood products) and approximately 77% of the areas under reforestation is done with species of this genus, mainly in acidic and poorly fertile soils. Lime application (liming) is a consensus strategy to reduce soil acidity and to supply Ca and Mg (as recommended for Eucalyptus) contents to crops nutrition. Liming can reduce soil metallic micronutrients (e.g., Cu and Zn) bioavailabilities, and Cu and Zn recommendation for Eucalyptus plants is not a consensus in Brazilian silviculture. Applying these micronutrients is recommended to supply the amount removed within forest harvesting products. In this sense, few studies investigated the combined application of lime and Cu plus Zn rates for Eucalyptus grown under tropical soils. In this study, the implications of those factors on soil chemical attributes, plant nutritional status and plant growth performance of Eucalyptus grandis were investigated. Variables evaluated included leaf area and leaf area index, chlorophyll and flavonoid content, and antioxidant metabolism performance [lipid peroxidation (malondialdehyde content), hydrogen peroxide content, and activity of antioxidant enzymes (i.e., superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase, guaiacol peroxidase, and glutathione peroxidase)]. Lime application increased soil pH and Ca and Mg availabilities, while Cu and Zn availabilities bioavailability into the soil was reduced. Overall, liming reduced soil Cu and Zn contents in residual fraction (bound to silicate minerals) but increased in fraction bound to organic matter (oxidizable). Liming augmented Cu, Fe, Mn, and Zn use efficiency, while Cu plus Zn fertilization increased enzymatic antioxidant performance of Eucalyptus plants. Eucalyptus grown in soil amended with lime had higher leaf area, leaf area index, leaf pigments, leaf Ca and Mg concentrations, while Cu and Zn concentrations were reduced. Eucalyptus grown under lime application associated with Cu plus Zn fertilization leads to better plant performance, which is observed through crop productivity improvement. Thus, the adoption of Cu plus Zn fertilization combined with the lime can be promising strategy to link balanced nutrition and optimize plant growth aimed to higher wood yield. In conclusion, our study brought new insights into the soil fertility, wood yields, leaf area and leaf area index, biochemical traits, antioxidant metabolism and nutritional status of the Eucalyptus plants under lime application associated with Cu and Zn fertilization.