Résumé
Silicon (Si) released as H4SiO4 by weathering of Si-containing solid phases is partly recycled through vegetation before its land-to-rivers transfer. By accumulating in terrestrial plants to a similar extent as some major macronutrients (0.1-10% Si dry weight), Si becomes largely mobile in the soil-plant system. Litter-fall leads to a substantial reactive biogenic silica pool in soil, which contributes to the release of dissolved Si (DSi) in soil solution. Understanding the biogeochemical cycle of silicon in surface environments and the DSi export from soils into rivers is crucial given that the marine primary bio-productivity depends on the availability of H4SiO4 for phytoplankton that requires Si. Continental fluxes of DSi seem to be deeply influenced by climate (temperature and runoff) as well as soil-vegetation systems. Therefore, continental areas can be characterized by various abilities to transfer DSi from soil-plant systems towards rivers. Here we pay special attention to those processes taking place in soil-plant systems and controlling the Si transfer towards rivers. We aim at identifying relevant geochemical tracers of Si pathways within the soil-plant system to obtain a better understanding of the origin of DSi exported towards rivers. In this review, we compare different soil-plant systems (weathering-unlimited and weathering-limited environments) and the variations of the geochemical tracers (Ge/Si ratios and delta Si-30) in DSi outputs. We recommend the use of biogeochemical tracers in combination with Si mass-balances and detailed physico-chemical characterization of soil-plant systems to allow better insight in the sources and fate of Si in these biogeochemical systems.
Auteurs, date et publication :
Auteurs J. -T. Cornelis , B. Delvaux , R. B. Georg , Y. Lucas , J. Ranger , S. Opfergelt
Publication : Biogeosciences
Date : 2025
Volume : 8
Issue : 1
Pages : 89-112
Catégorie(s)
#FORET Breuil #INRAERésumé
Unlike farmland, forests growing on acidic soils are among the terrestrial ecosystems that are the least influenced or amended by man. Forests which developed on acidic soils are characterized by an important stock of inorganic nutrients entrapped in poorly weatherable soil minerals. In this context, the mineral-weathering process is of great importance, since such minerals are not easily accessible to tree roots. To date, several bacterial genera have been noted for their ability to weather minerals and, in the case of some of them, to improve tree nutrition. Nevertheless, few studies have focused their analyses on mineral-weathering bacterial communities in relation to geochemical cycles and soil characteristics, their ecological origin, associated tree species and forest management practices. Here we discuss the heterogeneity of the mineral-weathering process in forest soils and present what is known concerning the taxonomic and functional characteristics of mineral-weathering bacteria, as well as the different locations where they have been isolated in forest soils. We also discuss the biotic and abiotic factors that may influence the distribution of these bacteria, such as the effect of tree species or forest management practices. (C) 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
Auteurs, date et publication :
Auteurs Stephane Uroz , Phil Oger , Cendrella Lepleux , Christelle Collignon , Pascale Frey-Klett , Marie-Pierre Turpault
Publication : Research in Microbiology
Date : 2011
Volume : 162
Issue : 9, SI
Pages : 820-831
Catégorie(s)
#FORET Breuil #INRAERésumé
Bacterial communities play an essential role in the sustainability of forest ecosystems by releasing from soil minerals the nutritive cations required not only for their own nutrition but also for that of trees. If it is admitted that the nutritional needs of trees vary during seasons, the seasonal dynamics of the mineral weathering bacterial communities colonizing the tree rhizosphere remain unknown. In this study, we characterized the mineral weathering efficacy of bacterial strains, from the rhizosphere and the adjacent bulk soil at four different seasons under two different tree species, the evergreen spruce and the deciduous beech, using a microplate assay that measures the quantity of iron released from biotite. We showed that the functional and taxonomic structures of the mineral weathering bacterial communities varied significantly with the tree species as well as with the season. Notably, the Burkholderia strains from the beech stand appeared more efficient to weather biotite that the one from the spruce stand. The mineral weathering efficacy of the bulk soil isolates did not vary during seasons under the beech stand whereas it was significantly higher for the spring and summer isolates from the spruce stand. The weathering efficacy of the rhizosphere isolates was significantly higher for the autumn isolates compared to the isolates sampled in the other seasons under the beech stand and in summer compared to the other seasons under spruce. These results suggest that seasonal differences do occur in forest soil bacterial communities and that evergreen and deciduous trees do not follow the same dynamic. (C) 2011 Elsevier Ltd. All rights reserved.
Auteurs, date et publication :
Auteurs C. Collignon , S. Uroz , M-P. Turpault , P. Frey-Klett
Publication : Soil Biology and Biochemistry
Date : 2011
Volume : 43
Issue : 10
Pages : 2012-2022
Catégorie(s)
#FORET Breuil #INRAERésumé
Aims The aim of this study was to assess the seasonal influence on the dynamics of exchangeable nutrients (K, Ca and Mg) in acidic and nutrient-poor forest soils, where nutrients can become limiting for tree growth. Methods The amounts of exchangeable base cations (K(+)+Ca(2+)+Mg(2+)) were measured in soil samples collected in three soil compartments (Bulk, Outer Rhizosphere, and Inner Rhizosphere) and in 4 months (November, February, May and August) under two stands of 31-year-old Norway spruce and beech in an acidic temperate forest. Results In all season, both rhizosphere compartments were enriched in exchangeable nutrients compared to bulk soil. This suggests that tree roots and root-associated microorganisms (bacteria and mycorrhizal fungi) increased nutrient availability through mineral weathering or mineralization processes, and thus could contribute to forest sustainability in nutrient-poor conditions. Interestingly, in contrast to beech, a drastic decrease of exchangeable base cations was observed in bulk soil of spruce between November and February (higher than 80% for K and Mg, and 100% for Ca). The relation between this decrease, Al solubility, and nitrate concentration are evoked in the discussion. Conclusion This study reveals that processes resulting from interactions between trees, microorganisms and soil influence not only the seasonal dynamics of nutrients in the root vicinity but also the bulk soil function.
Auteurs, date et publication :
Auteurs Christelle Collignon , Christophe Calvaruso , Marie-Pierre Turpault
Publication : Plant and Soil
Date : 2011
Volume : 349
Issue : 1-2, SI
Pages : 355-366
Catégorie(s)
#FORET Breuil #INRAERésumé
In acidic forest soils, aluminium can alter tree health due to its potential toxicity. Aluminium phytotoxicity is mainly influenced by its chemical form and its availability. As physical-chemical indicators of Al toxicity in soil, Al speciation in soil solutions and in the exchange complex was measured in the rhizosphere and the bulk soil of two tree species (Norway spruce (Picea abies (L.) Karst.) and European Beech (Fagus sylvatica L.) in an acidic soil and in 4 months (November, February, May and August) representing the four seasons in a year. In the bulk soil, Al toxicity was generally higher under Norway spruce than under beech. Furthermore, temporal changes in Al behaviour were identified under Norway spruce but not under beech. The monomeric Al in the soil solutions and the exchangeable Al in the solid soil increased significantly in February under Norway spruce and were positively correlated with nitrate concentration, suggesting that nitrate influence Al speciation and mobility under Norway spruce. In the rhizosphere, Al toxicity was restricted through Al complexation by organic compounds and by nutrient contents independently from the season. The ecological importance of the rhizosphere in Al detoxification is discussed. This study suggests that plant specific differences as well as seasonal changes in plant physiology, microbial activity and microclimatology influence aluminum toxicity in acid forest soils.
Auteurs, date et publication :
Auteurs C. Collignon , J. -P. Boudot , M. -P. Turpault
Publication : Plant and Soil
Date : 2012
Volume : 357
Issue : 1-2
Pages : 259-274
Catégorie(s)
#FORET Breuil #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 #INRAERésumé
Accurate nutrient budgets in forest ecosystems are needed in order to plan sustainable forest management on poor soils. Such budgets require precise measurements of water and nutrient leaching through the soil. This study aims to characterize the hydrological processes and compute hydrological budgets occurring in a very poor and acidic soil under a 30-year-old beech stand in the Morvan Mountains (France). A forest plot was set up with rain collectors, lysimeters and TDR probes, and we used a deuterated water tracing experiment and two hydrological models (BILJOU and HYDRUS-1D) to estimate the proportion of preferential and slow convective water flow, and to compute the influence of preferential flow paths on nutrient leaching. Preferential flow paths were evidenced by the deuterium tracing experiment. Tracer dynamic through the soil and soil water content variations were successively modeled. This approach enabled us to define the main condition leading to preferential flow generation (rainfall above 3.5 mm/h) and quantify the proportion of preferential flow (54%). Finally, the computed nutrient leaching fluxes of major elements Ca, Mg, NO3 and Al were strongly increased when considering preferential flow paths. The experimental and modeling approach proved to be complementary and we recommend the use of tracing experiments for better model calibration, especially when their outputs are used to compute nutrient leaching fluxes. (c) 2012 Elsevier B.V. All rights reserved.
Auteurs, date et publication :
Auteurs Gregory van der Heijden , Arnaud Legout , Benoit Pollier , Claude Brechet , Jacques Ranger , Etienne Dambrine
Publication : Geoderma
Date : 2013
Volume : 195
Pages : 12-22
Catégorie(s)
#FORET Breuil #INRAERésumé
Using nutrient budgets, it has been proven that atmospheric deposition of Mg and Ca sustains the fertility of forest ecosystems on base-poor soils. However the fate of this nutrient input within the ecosystem was presently unknown. Our hypothesis is that the biological cycling of these nutrients is very rapid and conservative to prevent further Mg and Ca losses most especially in ecosystems on base-poor soils. Stable isotopes of magnesium and calcium (Mg-26 and Ca-44) were used to trace the dynamics of throughfall Mg and Ca in the forest soil of a 35-year-old beech stand. The aim of the present study was to (1) understand the processes and the velocity of the incorporation of tracers in the biogeochemical cycles and (2) compute Mg and Ca budgets for the ecosystem by isotope dilution. Rainfall Mg and Ca were strongly and rapidly retained mainly by ion exchange in the thin OL litter-layer. However, Ca was much more strongly retained in the litter-layer than Mg. As a result, 2 years after the application of tracers (2012), 92 % of Mg-26 and 67 % of Ca-44 was released and transferred to the soil or taken up by trees. The vertical transfer of Mg was very slow only 15 % of Mg-26 was found below 15 cm depth in 2012. Ca was slower than Mg-26 only 9 % of Ca-44 was found below 5 cm depth. Although matrix flow was the main vertical transfer process of Ca and Mg, preferential transfer in macropores occurred. Overall, Mg was more rapidly leached through the soil profile than Ca because the soil CEC was mainly composed of organic charges which affinity for Ca is much higher than for Mg. 27 % of Mg-26 and 20 % of Ca-44 was found in tree biomass and total tracer recovery was close to 100 %. These results suggest that no tracers were lost to drainage over the 2 years. Finally, applying the isotopic dilution theory to the whole-ecosystem enabled us to estimate Mg and Ca budgets -0.9 kg ha(-1) year(-1) for Mg, which was close to computed input-output budgets -0.8 and 0 kg ha(-1) year(-1) for Ca, which was very different from input-output budgets (-3.1 kg ha(-1) year(-1)). Our results suggest that a Ca source is underestimated or not taken into account. Over all, organic matter of the litter-layer and in the soil profile played an essential role in the retention of throughfall Mg and Ca and their cycling within the forest ecosystem.
Auteurs, date et publication :
Auteurs Gregory van der Heijden , Arnaud Legout , Benoit Pollier , Jacques Ranger , Etienne Dambrine
Publication : Biogeochemistry
Date : 2014
Volume : 118
Issue : 1-3
Pages : 413-442
Catégorie(s)
#FORET Breuil #INRAERésumé
As wood harvests are expected to increase to satisfy the need for bio-energy in Europe, quantifying atmospheric nutrient inputs in forest ecosystems is essential for forest management. Current atmospheric measurements only take into account the 0.45μm fraction of atmospheric deposition, below the canopy, to study the influence of the canopy on APD, and to determine the influence of APD below canopy to nutrient input–output budgets with a focus on base cations calcium, magnesium and potassium, and phosphorus. APD was sampled every four weeks by passive collectors. We divided APD into an organic and a mineral fraction, respectively POM and MDD. MDD was divided into a soluble and a hardly soluble fraction in hydrogen peroxide, referred to as S-MDD and H-MDD, respectively. In order to better understand the influence of the canopy on APD, we studied APD in three pathways below the canopy (litterfall, stemflow and throughfall), and in open field. Our results indicated that APD in throughfall (123±64kgha−1year−1) was significantly higher and synchronic with that in open field (33±9kgha−1year−1) in the two study sites. This concerned both POM and MDD, suggesting a large interception of APD by foliar surfaces, which is rapidly washed off by rain within four weeks. Throughfall H-MDD was the main pathway with an average of 16±2kgha−1year−1. Stemflow and litterfall were neglected. In one study site, canopy intercepted about 8kgha−1year−1 of S-MDD. Although base cations and phosphorus inputs by APD are lower than those of <0.45μm deposition, they contributed from 5 to 32% to atmospheric deposition and improved the nutrient budget in one of the study sites.
Auteurs, date et publication :
Auteurs Emeline Lequy , Christophe Calvaruso , Sébastien Conil , Marie-Pierre Turpault
Publication : Science of The Total Environment
Date : 2014
Volume : 487
Pages : 206-215
Catégorie(s)
#FORET Breuil #FORET Montiers #INRAERésumé
The impacts of plant species on the microbial communities and physico-chemical characteristics of soil are well documented for many herbs, grasses and legumes but much less so for tree species. Here, we investigate by rRNA and ITS amplicon sequencing the diversity of microorganisms from the three domains of life (Archaea, Bacteria and Eukaryota: Fungi) in soil samples taken from the forest experimental site of Breuil-Chenue (France). We discovered significant differences in the abundance, composition and structure of the microbial communities associated with two phylogenetically distant tree species of the same age, deciduous European beech (Fagus sylvatica) and coniferous Norway spruce (Picea abies Karst), planted in the same soil. Our results suggest a significant effect of tree species on soil microbiota though in different ways for each of the three microbial groups. Fungal and archaeal community structures and compositions are mainly determined according to tree species, whereas bacterial communities differ to a great degree between rhizosphere and bulk soils, regardless of the tree species. These results were confirmed by quantitative PCR, which revealed significant enrichment of specific bacterial genera, such as Burkholderia and Collimonas, known for their ability to weather minerals within the tree root vicinity.
Auteurs, date et publication :
Auteurs S. Uroz , P. Oger , E. Tisserand , A. Cebron , M.-P. Turpault , M. Buee , W. De Boer , J. H. J. Leveau , P. Frey-Klett
Publication : Scientific Reports
Date : 2016
Volume : 6
Pages : 27756