Consequences of mixing Acacia mangium and Eucalyptus grandis trees on soil exploration by fine-roots down to a depth of 17 m
Résumé
Method Fine roots (diameter < 2 mm) were sampled in a randomized block design with three treatments: monospecific stands of Acacia mangium (100A), Eucalyptus grandis (100E), and mixed stands with 50% of each species (50A50E). Root ingrowth bags were installed at 4 depths (from 0.1 m to 6 m) in the three treatments within three different blocks, to study the fine-root production over 2 periods of 3 months. Results Down to 17 m depth, total fine-root biomass was 1127 g m−2 in 50A50E, 780 g m−2 in 100A and 714 g m−2 in 100E. Specific root length and specific root area were 110–150% higher in 50A50E than in 100A for Acacia mangium trees and 34% higher in 50A50E than in 100E for Eucalyptus grandis trees. Ingrowth bags showed that the capacity of fine roots to explore soil patches did not decrease down to a depth of 6 m for the two species. Conclusions Belowground interactions between Acacia mangium and Eucalyptus grandis trees greatly increased the exploration of very deep soil layers by fine roots, which is likely to enhance the uptake of soil resources. Mixing tree species might therefore increase the resilience of tropical planted forests through a better exploration of deep soils.
Auteurs, date et publication :
Auteurs Amandine Germon , Iraê Amaral Guerrini , Bruno Bordron , Jean-Pierre Bouillet , Yann Nouvellon , José Leonardo de Moraes Gonçalves , Christophe Jourdan , Ranieri Ribeiro Paula , Jean-Paul Laclau
Publication : Plant and Soil
Date : 2017