Mixed-species plantations of Acacia mangium and Eucalyptus grandis in Brazil : 2 Nitrogen accumulation in the stands and biological N2 fixation

The sustainability of plantation forests is closely dependent on soil nitrogen availability in short-rotation forests established on low-fertility soils. N2 fixation by A. mangium was quantified in 100A:0E and 50A:100E at age 18 and 30 months by the 15N natural abundance method and in 50A:100E at age 30 months by the 15N dilution method. The consistency of results obtained by isotopic methods was checked against observations of nodulation, Specific Acetylene Reduction Activity (SARA), as well as the dynamics of N accumulation within both species. At age 18 months, higher δ15N values found in A. mangium tree components than in E. grandis components prevented reliable estimations of the percentage of N derived from atmospheric fixation (%Ndfa). At age 30 months, %Ndfa estimated by natural abundance and by 15N dilution amounted to 10–20 and 60%, respectively. The amount of N derived from N2 fixation in the standing biomass was estimated at 62 kg N ha−1 in 100A:0E and 3 kg N ha−1 in 50A:100E by the 15N natural abundance method, and 16 kg N ha−1 in 50A:100E by the 15N dilution method. The total amount of atmospheric N2 fixed since planting was estimated at 66 kg N ha−1 in 100A:0E and 7 kg N ha−1 in 50A:100E by the 15N natural abundance method, and 31 kg N ha−1 in 50A:100E by the 15N dilution method. The most reliable estimation of N2 fixation was likely to be achieved using the 15N dilution method and sampling the whole plant.

Bibliographic Details

Main Authors:	50447 Bouillet, J.P. CIRAD, Montpellier (Francia), 84504 Laclau, J.P. (autor/a) CIRAD, Montpellier (Francia), 72397 Goncalves, J.L.M. (autor/a) USP, Piracicaba, Brazil, 96450 Moreira, Marcelo Z. (autor/a) Centro de Energía Nuclear na Agrícultura, Piracicaba, Brazil, 125571 Trivelin, P.C.O. (autor/a) Centro de Energía Nuclear na Agrícultura, Piracicaba, Brazil, 81746 Jourdan, C. (autor/a) CIRAD, Montpellier (Francia), 119035 Silva, E.V. (autor/a) USP, Piracicaba, Brazil, 105142 Piccolo, M.C. (autor/a) Centro de Energía Nuclear na Agrícultura, Piracicaba, Brazil, 125720 Tsai, S.M. (autor/a) Centro de Energía Nuclear na Agrícultura, Piracicaba, Brazil, 69801 Galiana, A. (autor/a) UMR LSTM, Montpellier, France
Format:	Texto biblioteca
Language:	eng
Published:	Amsterdam Elsevier 2008
Subjects:	ACACIA MANGIUM, EUCALYPTUS GRANDIS, PLANTACION FORESTAL, FIJACION DEL NITROGENO, ALMACENAMIENTO, BIOMASA, MEDICION, MODELOS, ECUACIONES ALOMETRICAS, ALOMETRIA, AGRICULTURA, FOREST PLANTATIONS, NITROGEN, STORAGE, BIOMASS, MEASUREMENT, MODELS, FORESTS,
Online Access:	https://www.sciencedirect.com/science/article/abs/pii/S0378112707008420
Tags:	Add Tag No Tags, Be the first to tag this record!