Ecophysiology and multivariate analysis for production of Tachigali vulgaris in Brazil: Influence of rainfall seasonality and fertilization

Abstract

Studies on fertilization management of species native to the Amazon for energy plantations contribute to the diversity of species use and reduce biological risk due to the excessive use of clones or hybrids of Eucalyptus. This study evaluates the effect of precipitation seasonality and phosphorus and potassium fertilization on gas exchange in a Tachigali vulgaris plantation. Three levels of P (zero, 65.2, 130.4 kg ha⁻¹) and three of K (zero, 100.0, 200.0 kg ha⁻¹) were applied in a 3 × 3 factorial randomized block design. Gas exchange measurements were conducted in April and November 2018. In low rainfall, high irradiance period, photosynthetic rates were up to four times higher than in the high rainfall period, reaching 20.3 μmol m⁻² s⁻¹ in the treatment with 130.4 g kg⁻¹ of P and 100.0 g kg⁻¹ of K. Factor analysis and principal component analysis reduced the initial eight gas exchange variables to two and three principal components in periods of high and low rainfall, respectively. The multivariate method used in this study readily identified variations in the variables as a function of rainfall, with high reliability in explaining the data set.

Keywords

Photosynthesis rate / Stomatal conductance / Principal component analysis / Factor analysis / Tachigali vulgaris