EUCAMIX

Ecological intensification of eucalyptus plantations through the association of nitrogen-fixing legume tree species

This project was carried out in close collaboration with the ANR-Systerra “Intens&Fix” project.

There has been a global increase in wood demand worldwide that is increasingly being met by forest plantations and especially, in Brazil, by eucalypt plantations (EP). However, the ability of these plantations to meet wood demand is limited by competing land uses and their sustainability, given serious long-term N and P deficits, is of major concern. Introducing N2-fixing species into EPs may increase stand production and N and P availability in the soil. The project proposes innovative alternatives to planting eucalypt as a sole crop to provide a high, sustainable level of wood production with reduced fertiliser applications and positive environmental impact. The project set out to develop an experimental approach for mixed plantations of Eucalyptus sp. and Acacia mangium in experimental stations with a network of trials in commercial companies. The study monitored water, C, N and P cycles and the ecological processes involved in their regulation, within both monocultures and mixed EPs. The biological interactions within and between the components of the system (trees, microorganisms, soil) were studied and quantified with respect to the use of natural resources. The project contributed to the improvement of methodological techniques and the documentation of competition/facilitation mechanisms for N and P bioavailability, and provided a form of silviculture based on ecological intensification, which was suitable for large areas of EP in Brazil.

Aims

The production of Eucalyptus plantations must be increased sustainably using innovative practices that are attractive to the stakeholders. The overall aim of the project was the ecological intensification of Eucalyptus plantations through the association of the N2-fixing-tree Acacia mangium to increase Eucalyptus plantation productivity and soil N and P availability. The specific aim was to address the inter- and intra-specific biophysical interactions within mixed Eucalyptus and A. mangium plantations

Initial results

The balance between positive and negative interactions drives wood production and C allocation among tree compartments. Durable N facilitation and complementarity between species in mixed Eucalyptus and Acacia plantations depends mainly on the lack of water stress. Nitrogen and P soil functioning and soil biodiversity changed rapidly after the introduction of A. mangium.

Publications

Bachega L.R., Bouillet J.P., Piccolo M.C., Saint-André L., Bouvet J.M., Nouvellon Y., Gonçalves J.L.M., Robin A., Laclau J.P., 2016. Decomposition of Eucalyptus grandis and Acacia mangium leaves and fine roots in tropical conditions did not meet the Home Field Advantage hypothesis. Forest Ecology and Management. 359, 33-43.

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Bouillet J.P., Laclau J.P., Gonçalves J.L.M., Voigtlaender M., Gava J.L., Leite F.P., Hakamada R., Mareschal L., Mabiala A., Tardy F., Levillain J., Deleporte P., Epron D., Nouvellon Y., 2013. Eucalyptus and Acacia tree growth and stand production over a full rotation in single- and mixed-species plantations across 5 sites in Brazil and Congo. Forest Ecology and Management, 301, 89–101.

Bini D., dos Santos C, Bouillet J.P., Gonçalves, J.L.M, Cardoso, E.J.B.N, 2013. Eucalyptus grandis and Acacia mangium in monoculture and intercropped plantations: Evolution of soil and litter microbial and chemical attributes during early stages of plant development. Applied soil Ecology, 63, 57-66.

Epron D., Nouvellon Y., Mareschal L., Moreira R.M., Koutika L.-S., Geneste B., Delgado-Rojas J.S., Laclau J.P., Sola G., Gonçalves J.L.M., Bouillet J.P., 2013. Partitioning of net primary production in Eucalyptus and Acacia stands and in mixed-species plantations: a comparison in two contrasting tropical environments. Forest Ecology and Management, 301,102–111.

Laclau J.P., Nouvellon Y., Reine C., Gonçalves J.L.M., Krushe A.V., Jourdan C., le Maire G., Bouillet J.P., 2013. Mixing Eucalyptus grandis and Acacia mangium trees leads to transgressive fine root over-yielding and exclusion of the weakest competitor from resource-rich soil layers. Oecologia, 172, 903–913.

le Maire, G., Nouvellon, Y., Christina, M., Ponzoni, F.J., Gonçalves, J.L.M., Bouillet, J.P., Laclau, J.P., 2012. Tree and stand light use efficiencies over a full rotation of single- and mixed-species Eucalyptus grandis and Acacia mangium plantations. Forest Ecology and Management. 288, 31-42.

Nouvellon Y., Laclau J.P., Epron D., Le Maire G, Bonnefond J.M., Gonçalves J.L.M., Bouillet J.P., 2012. Production and carbon allocation in monocultures and mixed-species plantations of Eucalyptus grandis and Acacia mangium in Brazil. Tree Physiology 32, 680-695.

Paula R.R., Bouillet J.P., Trivelin P.C.O., Zeller B., Gonçalves J.L.M., Nouvellon N., Bouvet J.M., Plassard C., Laclau J.P., 2015. Evidence of short-term belowground transfer of nitrogen from Acacia mangium to Eucalyptus grandis trees in a tropical planted forest. Soil Biology and Biochemistry 91, 99-108.

Voigtlaender M., Laclau J.P., de Gonçalves J.L.M., de Piccolo M.C., Moreira M.Z., Nouvellon Y., Ranger J., Bouillet J.P., 2012. Introducing Acacia mangium trees in Eucalyptus grandis plantations: Consequences for soil organic matter stocks and nitrogen mineralization. Plant and Soil 352, 99-111.

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