Fine root isotropy in Eucalyptus grandis plantations. Towards the prediction of root length densities from root counts on trench walls

Maurice Jérôme, Laclau Jean-Paul, Scorzoni Re Danilo, De Moraes Gonçalves Jose Leonardo, Nouvellon Yann, Bouillet Jean-Pierre, Stape Jose Luiz, Ranger Jacques, Behling Maurel, Chopart Jean-Louis. 2010. Fine root isotropy in Eucalyptus grandis plantations. Towards the prediction of root length densities from root counts on trench walls. Plant and Soil, 334 (1-2) : 261-275.

Quartile : Q1, Sujet : SOIL SCIENCE / Quartile : Q1, Sujet : AGRONOMY / Quartile : Q1, Sujet : PLANT SCIENCES

Résumé : The objectives of the study were to assess changes in fine root anisotropy and specific root lengths throughout the development of Eucalyptus grandis (W. Hill ex Maiden) plantations and to establish a predictive model of root length density (RLD) from root intercept counts on trench walls. Fine root densities (<1 mm in diameter) were studied in 6-, 12-, 22-, 28-, 54-, 68- and 72-month-old E. grandis plantations established on deep Ferralsols in southern Brazil. Fine root intercepts were counted on 3 faces of 90-198 soil cubes (1 dm3 in volume) in each stand and fine root lengths (L) were measured inside 576 soil cubes, sampled between the depths of 10 cm and 290 cm. The number of fine root intercepts was counted on one vertical face perpendicular to the planting row (Nt), one vertical face parallel to the planting row (Nl) and one horizontal face (Nh), for each soil cube sampled. An overall isotropy of fine roots was shown by paired Student's t-tests between the numbers of fine roots intersecting each face of soil cubes at most stand ages and soil depths. Specific root lengths decreased with stand age in the upper soil layers and tended to increase in deep soil layers at the end of the rotation. A linear regression established between Nt and L for all the soil cubes sampled accounted for 36% of the variability of L. Such a regression computed for mean Nt and L values at each sampling depth and stand age explained only 55% of the variability, as a result of large differences in the relationship between L and Nt depending on stand productivity. The equation RLD= 1.89*LAI*Nt, where LAI was the stand leaf area index (m2 m?2) and Nt was expressed as the number of root intercepts per cm2, made it possible to predict accurately (R2=0.84) and without bias the mean RLDs (cm cm?3) per depth in each stand, for the whole data set of 576 soil cubes sampled between 2 years of age and the end of the rotation.

Mots-clés Agrovoc : plantations, système racinaire, développement biologique, modèle de simulation, indice de surface foliaire, Eucalyptus grandis

Mots-clés géographiques Agrovoc : Sao Paulo

Classification Agris : F62 - Physiologie végétale - Croissance et développement
U10 - Informatique, mathématiques et statistiques

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• Maurice Jérôme, AgroParisTech (FRA)
• Laclau Jean-Paul, CIRAD-PERSYST-UPR Ecosystèmes de plantations (BRA) ORCID: 0000-0002-2506-214X
• Scorzoni Re Danilo, UNESP (BRA)
• De Moraes Gonçalves Jose Leonardo, USP (BRA)
• Nouvellon Yann, CIRAD-PERSYST-UPR Ecosystèmes de plantations (BRA)
• Bouillet Jean-Pierre, CIRAD-PERSYST-UPR Ecosystèmes de plantations (BRA)
• Stape Jose Luiz, North Carolina State University (USA)
• Ranger Jacques, INRA (FRA)
• Behling Maurel, USP (BRA)
• Chopart Jean-Louis, CIRAD-PERSYST-UPR SCA (REU)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/556379/)

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