Uso e eficiência do uso de água em plantações de Eucalyptus

Abstract

The projection of a 1.5 °C increase in global average temperatures and changes in precipitation regimes intensify extreme climatic events, threatening plant development and causing morphological, physiological, and biochemical alterations. In this context, water use efficiency (WUE) is a crucial parameter for understanding these changes. This study reviewed the scientific production of WUE through a bibliometric analysis of the topic, evaluating trends, methodologies, and the geographical distribution of studies, and investigating the WUE of Eucalyptus clones under different edaphoclimatic conditions in Brazil. Carbon-13 isotope discrimination (δ13C) was used to assess the WUE of two Eucalyptus clones: A1 (Eucalyptus urophylla), a fast-growing clone, and C3 (Eucalyptus grandis × E. camaldulensis), a drought- tolerant clone. Clone A1 exhibited higher water efficiency and productivity, whereas C3, despite its tolerance, showed lower WUE. Clone A1 had an ICA ranging from 13.53 to 48.82 Mg.ha−1.year−1 and an IMA from 4.07 to 28.09 Mg.ha−1.year−1, while clone C3 had an ICA ranging from 4.61 to 47.56 Mg.ha−1.year−1 and an IMA from 3.55 to 31.64 Mg.ha−1.year−1. The δ13C values ranged from -29.35‰ to -26.63‰ for A1 and from -30.39‰ to -27.33‰ for C3, with a negative correlation between δ13C and WUE. The models had R2 values from 0.54 to 0.97, RMSE ranging from 32.40% to 21.2%, and AIC values from 12.60 to 0.66. The results highlight the relevance of δ13C as a tool for estimating WUE and guiding clonal allocation in forest plantations in dry regions.