Desempenho morfofisiológico e qualidade de mudas de Corymbia citriodora e Eucalyptus urophylla submetidas à aplicação de biofertilizantes microbianos

Abstract

The production of high-quality forest seedlings is essential for the success of commercial plantations and sustainable silvicultural systems, with the nursery phase playing a fundamental role in the initial establishment of plants. This study evaluated the morphological, biometric, and physiological performance of Corymbia citriodora and Eucalyptus urophylla seedlings subjected to the application of different microbial biofertilizer formulations, applied individually and in combination, compared with conventional management without inoculation. The experiments were conducted in a nursery under a completely randomized design in a 5 × 2 factorial arrangement, consisting of five treatments (BARVAR+N, BARVAR+P, BARVAR+K, MIX NPK, and a control) and two evaluation periods (30 and 60 days). Morphological, biometric, and physiological parameters were evaluated, including height, root collar diameter, root volume, shoot, root, and total dry mass, lignification index, and Dickson Quality Index (DQI). In both species, significant growth was observed between 30 and 60 days, with biometric variables showing greater sensitivity to the treatments. The specific biofertilizers BARVAR+K and BARVAR+N promoted the greatest increases in root volume and biomass accumulation, resulting in seedlings with improved morphophysiological balance. In C. citriodora, BARVAR+K produced the highest total dry mass and DQI values, whereas in E. urophylla, BARVAR+K and BARVAR+N showed the best performance, reaching total dry mass values of up to 0.21 g, root volume of up to 2.30 mL, and a maximum DQI of 0.11 at 60 days. Correlation analysis indicated that seedling quality was directly associated with biomass accumulation and distribution rather than with isolated morphological dimensions. It is concluded that specific microbial biofertilizers, especially BARVAR+K and BARVAR+N, constitute a promising alternative for the production of high-quality forest seedlings, although longer cultivation periods are required for the full expression of physiological quality.