Nutrient supply modulates species interactions belowground: dynamics and traits of fine roots in mixed plantations of Eucalyptus and Acacia mangium

• Autor(a) principal: Bordron, B.
• Data de Publicação: 2021
• Outros Autores: Germon, A. [UNESP], Laclau, J. P. [UNESP], Oliveira, I. R., Robin, A., Jourdan, C., Paula, R. R., Pinheiro, R. C. [UNESP], Guillemot, J., Gonçalves, J. L.M., Bouillet, J. P.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1007/s11104-020-04755-2; http://hdl.handle.net/11449/205791
• topic: Competition; Facilitation; Ferralsol soil; Fertilization; Mixed-species plantations

Aims: Belowground interactions are still poorly understood in mixed-species forests. We investigated the effects of soil fertility on belowground processes in mixed planted forests. Methods: The dynamics and traits of Eucalyptus and Acacia mangium fine roots (diameter < 2 mm) in plantations with 50% of each species were studied in a randomized block design established in a nutrient depleted soil. Stands with NPK fertilization applied at planting (F+) were compared to unfertilized stands (F-). Results: In the 0–15 cm soil layer, Eucalyptus root mass density (RMD) was higher than Acacia RMD by 50% in F+ and 10% in F-, considering both ages. At 34 months of age, Eucalyptus RMD was 94% higher near Acacia trees than near Eucalyptus trees in F-. In this layer, Eucalyptus specific root length (SRL) was 21% higher than Acacia SRL at 16 months of age and was 10% higher in F- than in F+ at 34 months of age. The cumulative Eucalyptus fine root length production between 16 and 34 months was 66% higher in F- than in F+ in the 0–1 m soil layer. Conclusions: Fertilization increased the competition between species and led to a partial exclusion of Acacia fine roots from the nutrient-rich topsoil. Soil exploration by Eucalyptus roots in the vicinity of Acacia trees was higher in F- than in F+, which suggests that unfertilized trees benefited from facilitation through higher soil N availability and direct N transfer from Acacia trees.