Résumé
Compared to conifers, broadleaf forests are less prone to soil and water acidification, because (1) they often have soils with larger exchangeable base cation pools, (2) the pollution scavenging capacity of deciduous trees is lower, and (3) they grow more slowly and are often less intensively managed. Since the 1980s, atmospheric deposition acidity has strongly decreased in forest ecosystems, so that the present acidification status of broadleaf forests should be improving. We used a 35 year-old beech plot in the Morvan Mountains (Burgundy, France) to question past and present acidification processes in broadleaf ecosystems. Soil exchangeable Mg, Ca and K pools measured from samples collected in 1974 and 2001 were compared and input-output budgets were computed over the 2003-2008 period. The objectives were (i) to assess Mg and Ca pool size changes over 1974-2008, (ii) to discuss the potential causes of these changes and, (iii) discuss the limits of conventional methods to study nutrient pool size changes (soil data comparison and nutrient budgets). Soil exchangeable Mg pools decreased during the 1974-2001 period while Ca and K pools remained constant, and very small. Soil solution monitoring and input-output budgets over the 2003-2008 period suggested an ongoing loss of exchangeable Ca and Mg, partly due to the desorption of sulphate from the soil which induced Mg, Ca and K depletion. Given the very low concentration in exchangeable base cations, and assuming no change in soil spatial variability, we computed that resampling soils at 10 years intervals may not unequivocally demonstrate a gain/loss of exchangeable base cations. Foliar Mg concentrations were continuously below the deficiency level, K and N concentrations decreased but Ca did not. From this, we discuss the validity/limits of the different approaches used, how the ecosystem can cope with such low levels of nutrients, and the fluxes and processes within the ecosystem that should be investigated in this perspective. (C) 2013 Elsevier B.V. All rights reserved.
Auteurs, date et publication :
Auteurs Gregory van der Heijden , Arnaud Legout , Benoit Pollier , Louis Mareschal , Marie-Pierre Turpault , Jacques Ranger , Etienne Dambrine
Publication : Forest Ecology and Management
Date : 2013
Volume : 293
Pages : 65-78
Catégorie(s)
#FORET Breuil #INRAERésumé
This study describes the Aeolian dust deposition (ADD) in 4 sites of Northern France. Between December 2009 and March 2012, we sampled (i) Aeolian dust every four weeks, and (ii) 6 episodes of forecasted high atmospheric dust load mainly from the Saharan desert, the largest source of Aeolian dust in the world. These samples were treated with oxygen peroxide to remove organic matter so as to only compare the mineral fraction of the samples in the 4 sampling sites and to analyze their mineralogy. The solid samples contained the hardly soluble part of Aeolian dust (H-ADD). Its deposition was of 1.9 Æ 0.3 g mÀ2 yearÀ1 with a seasonal pattern of high deposition from spring to early autumn and a low deposition in winter. H-ADD deposition during the forecasted episodes of high atmospheric load did not systematically exceed the deposition rate during the rest of the sampling period. This indicates that such episodes little contributed to the annual H-ADD rate. The mineralogy revealed a heterogeneous set of minerals dominated by silicates with a common basis of major types (quartz, feldspars, mica, chlorite, kaolinite and interlayered clay minerals in every sample) with randomly trace minerals (Fe-oxides, sulfates, amphibole, talc, gibbsite and carbonates). The chemistry of H-ADD led to a dominant input of Si (up to 4.4 kg haÀ1 yearÀ1), while the nutrients inputs of Ca, K, Mg and P from ADD and the atmospheric organics (APD) in openfield were together of 1.5 Æ 0.5 kg haÀ1 yearÀ1 with a high contribution of soluble minerals and organic matter of ca. 40% for Mg and K, and of ca. 80% for Ca and P. Nutrient inputs from APD are especially an interesting source of P for forests developed on acidic soils.
Auteurs, date et publication :
Auteurs Émeline Lequy , Arnaud Legout , Sébastien Conil , Marie-Pierre Turpault
Publication : Atmospheric Environment
Date : 2025
Pages : 10
Catégorie(s)
#FORET Breuil #FORET Montiers #INRAERésumé
For forest ecosystems, the relationship between root biomass, root growth and soil nitrification is still debated. Following repeated findings of significant differences in soil nitrification beneath comparable stands at the Breuil experimental site, a reciprocal soil exchange experiment combining high (H)- and low (L)-nitrifying stands was conducted to highlight the effect of tree root colonization on the control of nitrification. Soil percent nitrification and fine root biomass were measured in undisturbed and in transplanted soil cores after 16 and 28 months. In undisturbed soils, the fine root biomass varied by tree species and explained only 14% of the variation in percent nitrification. In transplanted soil cores, percent nitrification converged, at different rates, towards values close to those measured in the undisturbed soil at the receptor stands. On the one hand, percent nitrification increased rapidly in soil cores from L transferred to H, while soil core colonization by roots remained low during the study period. Soil cores might have been colonized by active nitrifiers from their new environment, or/and the activity of the nitrifiers originally present was less suppressed by root activity in their new environment. On the other hand, percent nitrification decreased progressively in soil cores from H transferred to L as root colonization increased. This suggests that root colonization reduced nitrifier population and activity. Our findings suggest that the often-reported influence of forest species on soil nitrification is probably multifactorial but the tree root colonization contributes.
Auteurs, date et publication :
Auteurs K. S. Andrianarisoa , B. Zeller , J. Ranger , S. Bienaime , E. Dambrine
Publication : Soild Use and Management
Date : 2017
Volume : 33
Issue : 1
Pages : 45-53
Catégorie(s)
#FORET Breuil #INRAERésumé
Mineral amendment (i.e. calcium, phosphorous, potassium and/or magnesium) is a management practice used in forestry to improve nutrient availability and recover soil fertility, especially in nutrient-poor forest ecosystems. However, whether this amendment can lead to modifications of the soil characteristics and an improvement in tree growth, and its impact on the soil bacterial communities, especially the mineral weathering bacterial communities, remains poorly documented. In this study, we investigated the short-term impact of a mineral amendment on the taxonomic and functional structure of the mineral weathering bacterial communities. To do this, a plantation of four-year old oak (Quercus petraea) trees amended with or without dolomite [CaMg(CO3)(2)] was established in the experimental forest site of Breuil-Chenue, which is characterized by an acidic soil and a low availability of calcium and magnesium. Three years after amendment, soil samples were used to isolate bacteria as well as to determine the soil characteristics and the metabolic potentials of these soil microbial communities. Based on a bioassay for quantifying the solubilisation of inorganic phosphorous, we demonstrate that the bacterial isolates coming from the non-amended bulk soil were significantly more efficient than those from the amended bulk soil. No difference was observed between the bacterial isolates coming from the amended and non-amended rhizospheres. Notably, the taxonomic analyses revealed a dominance of bacterial isolates belonging to the Burkholderia genus in both samples. Overall, our results suggest that the bioavailability of nutritive cations into soil impacts the distribution and the efficacy of mineral weathering bacterial communities coming from the soil but not those coming from the rhizosphere. (C) 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
Auteurs, date et publication :
Auteurs C. Lepleux , S. Uroz , C. Collignon , J. -L. Churin , M. -P. Turpault , P. Frey-Klett
Publication : Research in Microbiology
Date : 2013
Volume : 164
Issue : 7
Pages : 729-739