Normas e determinação de faixas de suficiência para diagnose foliar com base no crescimento relativo de eucalipto

• Ano de defesa: 2010
• Autor(a) principal: Fernandes, Loane Vaz
• Orientador(a): Barros, Nairam Félix de
• Banca de defesa: Paiva, Haroldo Nogueira de , Venegas, Victor Hugo Alvarez
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado 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: Eucalipto; Diagnose nutricional; DRIS
• Palavras-chave em Inglês: Eucalypt; Nutritional diagnosis; DRIS
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/5440

The eucalyptus plantations in Brazil cover 4.3 Mha of which 22% is in the state of Sao Paulo. Several studies conclude that there is close and positive correlation between nutrient content and eucalyptus growth rate, and nutrient contents in the leaves reflect the flow of water and nutrients in the soil and correlate with productivity. Thus, the nutritional diagnosis based on tissue analysis can be used as a complementary tool to soil analysis to support crop nutritional management. Among the existing methods of plant nutrient diagnosis, that proposed by Kenworthy (KW) evaluates the balance of nutrients, considering each nutrient individually and the variability of nutrient content in the reference population. On the other hand, the Integrated Diagnosis and Recommendation (DRIS), proposed by Beaufils, evaluates the nutrient equilibrium through the ratio between nutrients. For both it is necessary to construct a set of nutrient standards. The objectives of this work were 1) to obtain standards for KW and DRIS methods, applicable to the diagnosis of nutritional status, based on foliar analysis of young eucalyptus plantations in the state of São Paulo, Brazil; 2) to evaluate the degree of universality of the norms or standards and diagnosis; 3) to evaluate the influence of excluding one or more nutrients showing high contents and high variability in their contents on the diagnosis and on the equilibrium of other nutrients; 4) to develop an alternative method with high biologic meaning, for the definition of sufficiency ranges for the KW and DRIS indexes; 5) to contribute to the improvement of the software NUTREELYPTUS, for leaf nutrient diagnosis. We used database from 1,150 plots of young eucalyptus plantations from which leaves were collected for analysis. The available information included N, P, K, Ca, Mg, S, Cu, Fe, Zn, Mn, and B contents and tree stem height. This stratification was performed by determining the reference population, for which height was greater than average height. We calculated specific (by age and region of cultivation, genetic material, previous crop and textural class) and general (by forest company and for the state of São Paulo) sets of standards. Specific standards were compared with those taken as general standards for each situation by the t test for means and F test for variances. Then, using NUTREELYPTUS, parameterized with these standards (specific and general) and ranges of sufficiency, we obtained the diagnosis of the nutritional status of plantations showing low productivity considering the balance sheet (KW indexes) and equilibrium (DRIS indexes and Potential Response to Fertilization - PRA classes), which were compared, at plot level, based on the frequency of concordant diagnostics (FDC). We used the methods of the Boundary Region (BR) and Mathematics Relative Chance (ChMR) to obtain reference values with greater biological significance. Relevant sets of specific standards were obtained for the diagnosis of nutritional status of young eucalyptus plantations in São Paulo State. The degree of universality of KW and DRIS norms varies with the parameter used (mean, variance, or both together) and, independently of the parameter, is smaller than that of diagnostics made using these standards. For a given company, the high values of FDC allow general standards to be used. Excluding Fe and Mn, nutrients for which the average overall contents were elevated and the variability highest, increases the sensitivity of the diagnostic of nutritional equilibrium, but do not change the degree of universality of the diagnoses made. The KW and DRIS indexes obtained by BF and ChMR can be utilized to obtain the limits of sufficiency ranges with greater biological meaning, seeking the interpretation of foliar analyses. The use of these new limits of sufficiency ranges has little effect on the FDC obtained with specific or general standards. For assessing the nutritional status of young eucalyptus plantations it is recommended to use the limits of sufficiency ranges of KW and DRIS obtained by ChMR method, as proposed in this research. Further studies are needed in order to correlate the nutritional status of young eucalyptus plantations to yield at the harvest age.