Determining the distributions of soil carbon and nitrogen in particle size fractions using near-infrared reflectance spectrum of bulk soil samples

Bernard G. Barthès (1) , Didier Brunet (1) , Edmond Hien (2) , Frank Enjalric (3, 4) , Sofian Conche (1) , Grégoire T. Freschet (1) , Rémi d'Annunzio (5) , Joële Toucet-Louri (1)

1 SEQBIO - Séquestration du carbone et bio-fonctionnement des sols : effets des modes de gestion des agro-écosystèmes tropicaux
2 UFR SVT
3 UPR1 Couverts permanents - Systèmes de semis direct sous couverture végétal-GSDM
4 Cirad-PERSYST - Département Performances des systèmes de production et de transformation tropicaux
5 LERFoB - Laboratoire d'Etudes des Ressources Forêt-Bois

This study aimed at assessing the potential of near-infrared reflectance spectroscopy (NIRS) for determining the distribution of soil organic matter (SOM) in particle size fractions, which has rarely been attempted. This was done on sandy soils from Burkina Faso (three sites) and Congo-Brazzaville (one site). Over the total sample set, NIRS accurately predicted carbon (C) and nitrogen (N) concentrations (g kg(-1) fraction) in the fraction <20 µm. When considering Burkina Faso only, predictions were improved in general; those of C and N amounts (g kg(-1) soil) became accurate for the fraction <20 µm but not for the coarser fractions, probably due to heterogeneous SOM repartition. However, most SOM being <20 µm in general, NIRS could be considered promising for determining SOM size distribution.

Mots clés: Soil organic matter; Particle size fractions; Near infrared reflectance spectroscopy (NIRS); Multivariate regression

Domaines: Sciences de l'environnement

Bernard G. Barthès, Didier Brunet, Edmond Hien, Frank Enjalric, Sofian Conche, et al.. Determining the distributions of soil carbon and nitrogen in particle size fractions using near-infrared reflectance spectrum of bulk soil samples. Soil Biology and Biochemistry, 2008, 40 (6), pp.1533-1537. ⟨10.1016/j.soilbio.2007.12.023⟩. ⟨hal-01195059⟩