Résumé
Soil compaction is a major contributor to forest soil degradation. To make a decision on soil remediation, both the soil compactness after heavy traffic of forest machinery and the natural soil recovery rate must be estimated. We estimated the impact of heavy traffic on soil specific volume (V) and its recovery rate on two forest sites by yearly collecting steel cylinders close to field capacity, as currently recommended, at different depths (D) during 3 to 4 yr. Though collected at water contents (w) as homogeneous as possible, the comparison of sample volumes led to inconsistent results. Using w as covariate was necessary to quantify the initial compaction and the V recovery with time and D. Moreover, compared to the soil V and w determined with shrinkage analysis, some field values were very large, suggesting an artifact due to hammering the cylinder at large w. The surface layer (0-10 cm) of the less compacted site showed no residual compactness 3 yr after heavy traffic and the 10- to 20-cm layer compactness decreased significantly with time. The compactness of the second site decreased significantly only in the 0- to 10-cm layer, and the recovery was still ongoing after the third year of monitoring. This site had less swelling clays and larger clay content. The recovery of the soil volume was attributed to shrink-swell processes. Longer monitoring is required to validate these trends, and further research should evaluate the need for more accurate monitoring based on shrinkage analysis and the use of soil organic carbon (SOC) and clay content as covariates.
Auteurs, date et publication :
Auteurs Noemie Goutal , Pascal Boivin , Jacques Ranger
Publication : Soil Science Society of America Journal
Date : 2012
Volume : 76
Issue : 4
Pages : 1426-1435
Catégorie(s)
#FORET Azerailles-Clermont #INRAERésumé
Aluminium (Al) and iron (Fe) play a key role in pedogenetic processes; however, short-term changes in Al- and Fe-bearing secondary minerals are little documented. In this study, Al and Fe dynamics in the solid phase have been evaluated in three soil compartments (bulk, rhizosphere outer, corresponding to soil volume detached from fresh roots, and rhizosphere inner, corresponding to soil volume detached from dried roots) and during 4 months (November, February, May and August) in an acid soil with podzolic features at its surface. Soil samples were collected from under Norway spruce (Picea abies (L.) Karst.) at three depths (03, 310 and 1023 cm) and were sieved at 200 mu m. The Al and Fe forms were extracted with different solutions: potassium chloride (AlKCl and FeKCl), oxalate (Alo and Feo), tri-citrate (Alc) and dithionite-citrate-bicarbonate (Fed). The influence of spruce roots and seasons on the dynamics of Al and Fe (precipitation and dissolution reactions) was observed. The rhizosphere effect on Fed varied with sampling dates. Thus, Fed-Feo decreased between winter and spring in the rhizosphere inner soil only (decrease of 40%). In contrast, Alc was greater in the bulk soil than in both rhizosphere soils for all seasons. The strongest variations in Al were observed at depth, especially in the bulk and the rhizosphere outer soil, where Alc-Alo decreased drastically between winter and spring (from 50 to 60%). The seasonal dynamics of the podzolization process are discussed. This study shows that Al- and Fe-bearing secondary minerals can quickly react to environmental changes, suggesting that these minerals could be markers of currently active functioning of soils.
Auteurs, date et publication :
Auteurs C. Collignon , J. Ranger , M. P. Turpault
Publication : European Journal of Soil Science
Date : 2012
Volume : 63
Issue : 5, SI
Pages : 592-602
Catégorie(s)
#FORET Breuil #INRAEAuteurs, date et publication :
Auteurs Laurent Lagadic , Virginie Ducrot
Date : 2012
Catégorie(s)
#INRAE #PEARLRésumé
Brazilian Eucalyptus plantations are some of the most productive forest plantations in the world, sustaining mean growth rates of 25 Mg ha_1 year_1 (50 m3 ha_1 year_1) over the 4.7 million hectares planted across the country. To better understand forest productivity, studies at the stand scale need to be coupled with tree level evaluations of the production ecology (the assessment of wood production as a function of crown light absorption and light use efficiency). The soil clay content (_20% to _40%), topography and historical land use of the experimental site generated a natural gradient in productivity. We measured (from 6 to 7 years after planting) stem wood dry biomass growth and estimated light absorption and light use efficiency at the tree level with a three-dimensional array model (MAESTRA) in 12 plots within a seed-origin Eucalyptus grandis plantation. We investigated the hypothesis that dominant trees (the 20% largest) are more productive than non-dominant trees (the 20% smallest) as a result of greater light absorption and light use efficiency; and that with increasing productivity across plots, dominant trees would show larger increases in light use and light use efficiency in comparison to non-dominant trees. The 20% smallest of the trees averaged 10.6 kg of stem wood dry biomass (1.6 kg of stem wood growth during the last year of the rotation), compared with 185 kg per stem wood in the 20% largest of trees (34 kg of stem wood growth over the same period). The smallest trees contained 7.2% of the leaf area as compared to the largest trees (3.0 m2 versus 41.7 m2), and they absorbed only 6.7% as much light (2.2 versus 32.8 GJ year_1). The smallest trees grew at about 4.7% of the rate of the largest trees, which is a smaller percentage than the difference in absorbed photosynthetically active radiation; therefore the light use efficiency was lower for the smallest trees (0.75 kg GJ_1 versus 1.03 kg GJ_1). Our results show the significant contribution of dominant trees to stand productivity and the importance of evaluating production ecology at the individual tree scale. (Résumé d'auteur)
Auteurs, date et publication :
Auteurs Otávio Camargo Campoe , Jose Luiz Stape , Yann Nouvellon , Jean-Paul Laclau , William L. Bauerle , Dan Binkley , Guerric Le Maire
Publication : Forest Ecology and Management
Date : 2025
Volume : 288
Pages : 14-20
Catégorie(s)
#CIRAD #FORET Itatinga #INRAEAuteurs, date et publication :
Auteurs Elke
Date : 2025
Catégorie(s)
#INRAE #PEARLAuteurs, date et publication :
Auteurs Junior C. R. Sette , J. P. Laclau , M. Tomazello Filho , R. M. Moreira , J. P. Bouillet , J. Ranger , J. C. Raposo Almeida
Publication : Trees
Date : 2025
Volume : 27
Issue : 4
Pages : 827-839.
Catégorie(s)
#CIRAD #FORET Itatinga #INRAERésumé
Understanding the light absorption and light use efficiency of each species at the tree scale is essential to disentangle the effects of intra- and inter-species interactions on productivity in mixed-species forest plantations. A complete randomized block design was set up using Eucalyptus grandis (E) and Acacia mangium (A), which is a N2-fixing species, planted in monospecific stands (100A, 100E) and in additive (25A:100E, 50A:100E, 100A:100E) and replacement (50A:50E) mixtures. Tree size and biomass were monitored over the complete rotation (6 years). The absorbed photosynthetically active radiation (APAR) for each tree in the experiment was simulated over the full rotation with the MAESTRA model. Measurements of tree leaf area, leaf angle distributions, leaf area density, and leaf and soil optical properties were performed to parameterize this model. The APAR and the ratio of stem biomass increment divided by the APAR (which is a measure of the Light Use Efficiency [LUE] for stem production) were calculated at tree and plot scales for each year of the rotation. The LUE of the 100E stand increased with age until stabilizing at 4 years of age, while the LUE of the 100A stand decreased between 2 and 4 years of age and increased between the two last years of the rotation. Eucalyptus trees dominated Acacia trees in mixed plantations. The stratification of the canopy led to an increase of stand Leaf Area Index (LAI) and APAR compared to monospecific plantations. However, both Eucalyptus and Acacia LUE decreased at the end of the rotation in the mixed-species stands, with the decrease occurring more markedly in Acacia, and the final stem biomass of the stand was not enhanced in mixed-species plantations compared with the average of the pure stands. Our results indicate that a stratified canopy may offer the potential benefit of capturing more light in mixed-species forests, but this may be negated if another resource deficiency prevents trees from converting intercepted radiation into dry matter. Mixed-species plantations should be established at sufficiently rainfed sites to maximize LUE, and appropriate fertilizer regimes should be applied. (Résumé d'auteur)
Auteurs, date et publication :
Auteurs Guerric Le Maire , Yann Nouvellon , Mathias Christina , Flávio Jorge Ponzoni , José Leonardo M. Gonçalves , Jean-Pierre Bouillet , Jean-Paul Laclau
Publication : Forest Ecology and Management
Date : 2025
Volume : 288
Pages : 31-42
Catégorie(s)
#CIRAD #FORET Itatinga #INRAEAuteurs, date et publication :
Auteurs Lise Thouvenot
Date : 2025
Catégorie(s)
#INRAE #PEARLAuteurs, date et publication :
Auteurs J. Tasker , C. Veauvy , S. Morris , C. Askem , V. Ducrot , L. Lagadic , D. Azam , M. Coke , R. Brown , H. Holbech , K. Ruppert , J. Oehlman , L. Weltje , M. Roberts , T.H. Hutchinson
Date : 2025
Catégorie(s)
#INRAE #PEARLAuteurs, date et publication :
Auteurs Jean-François Mangot , Isabelle Domaizon , Najwa Taib , Nemr Marouni , Emilie Duffaud , Gisèle Bronner , Didier Debroas
Publication : Environmental Microbiology
Date : 2025
Volume : 15
Issue : 6
Pages : 1745-1758