Nutritional status of Eucalyptus grandis clones evaluated by critical level and DRIS methods

Paulo Guilherme Salvador Wadt

doi:10.1590/s0100-67622004000100003

Abstract

Nutritional status of eight 1.0 and 4.7 years old clones of Eucalyptus grandis, cultivated in a medium textured Ustults - US - and a Quartzipsamments - PS - soils, in Lençóis Paulista, São Paulo, were evaluated by the Diagnosis and Recommendation Integrated System (DRIS) and Critical Level (CL) methods. Based on multivariate discriminant analysis, the DRIS indices described the nutritional status of trees better in relation to tree age and soil type than in relation to nutrient composition. Spearman's correlation coefficients showed statistically significant relationships between volumetric tree growth and nutrients when applying DRIS indices or foliar nutrient concentrations. However, the DRIS indices indicated a lower number of trees with nutritional deficiencies, in relation to the CL method. According to the CL method, P, S, and Ca were deficient in the majority of the soils and tree age categories. By the DRIS method, Ca was the only deficient nutrient in PS soils, and appeared to be particularly limited in one-year-old trees. In conclusion, the DRIS method was more efficient than the CL method in evaluating the nutritional status of eucalyptus trees.

Highlights

In Brazil, eucalyptus has been cultivated generally on savanna soils of low natural fertility (Barros & Novais, 1996; Reis & Barros, 1990) with limited capacity to support production caused by significant declines in mineral reserves by continuous harvest cycles (Leal et al, 1988).the nutritional balance in eucalyptus plantations is negative, because nutrient take uptake is higher than the nutrient inputs.Sociedade de Investigações FlorestaisR
The Diagnosis and Recommendation Integrated System (DRIS) norms were obtained through quantification of N, P, K, Ca, Mg, S, B, Zn, Mn, Fe and Cu nutrient composition of 1,986 sites of commercial 4.5 to 10 year old stands cultivated with Eucalyptus grandis x E. urophylla clones in the states of Espirito Santo and Bahia, Brazil (Wadt & Novais, 1999)
The DRIS method classified satisfactorily the actual grouping of trees cultivated in PS soil, failing only in two tree groupings of 1.0 year old trees cultivated in US soil (Table 2)

Summary

Introduction

In Brazil, eucalyptus has been cultivated generally on savanna soils of low natural fertility (Barros & Novais, 1996; Reis & Barros, 1990) with limited capacity to support production caused by significant declines in mineral reserves by continuous harvest cycles (Leal et al, 1988).the nutritional balance in eucalyptus plantations is negative, because nutrient take uptake is higher than the nutrient inputs. WADT, P.G.S. Fertilizer application on soil under eucalyptus plantations is undoubtedly expensive because of the extensive plantation areas. It is necessary to develop methods of diagnosis and fertilizer recommendations which can lead to improved fertilizer recommendation and forestry productivity. The nutrient diagnostic method should identify cases in which a nutrient limits yield. Situations should be identified, in which the nutrient does not limit yield, in order to optimize biological and economic productivity

Objectives

Methods

Results