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Soil microbial necromass as an essential phosphorus reservoir in forest nutrition(NecroPool)

English title Soil microbial necromass as an essential phosphorus reservoir in forest nutrition(NecroPool)
Applicant Spielvogel Sandra
Number 171173
Funding scheme Project funding (Div. I-III)
Research institution Geographisches Institut Universität Bern
Institution of higher education University of Berne - BE
Main discipline Pedology
Start/End 01.06.2017 - 31.10.2020
Approved amount 113'399.00
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All Disciplines (2)

Discipline
Pedology
Geochemistry

Keywords (4)

Mikrobielle Biomasse; Phosphor; Waldböden; Waldernährung

Lay Summary (German)

Lead
Mikrobielle Nekromasse: Ein wesentlicher Phosphorspeicher für die Waldernährung?Wälder decken trotz niedriger Phosphorgehalte (P) im Boden ihren P-Bedarf, indem sieschwer verfügbare P-Formen erschließen und P im System halten. Mikroorganismen sind dazuin der Lage P aus nicht pflanzenverfügbaren Quellen zu mobilisieren, konkurrieren abergleichzeitig mit Pflanzen um limitierte P Ressourcen. Dieses Projekt ermittelt die Bedeutung von P aus abgestorbenen Mikroorganismen als temporärer P-Speicher und für die Ernährung von Waldökosystemen.
Lay summary

Wälder decken trotz niedriger Phosphor-(P)versorgung ihren P-Bedarf, indem sie schwer verfügbare P-Formen erschließen und P im System halten. Mikroorganismen sind dazu in der Lage P aus nicht pflanzenverfügbaren Quellen zu mobilisieren, konkurrieren aber gleichzeitig mit Pflanzen um limitierte P Ressourcen. Obwohl der Anteil mikrobieller Biomasse mehr als 10% der P-Vorräte des Bodens ausmachen kann, wurde er bisher kaum als P Quelle in der Waldernährung berücksichtigt. Diese Studie will die Bedeutung mikrobieller Bio- und Nekromasse als Quelle für die P-Versorgung von Buchen quantifizieren. Dabei werden die räumliche Variabilität der P-Verteilung und Unterschiede zwischen P-Kreisläufen acquirierender und recycelnder Forstökosysteme berücksichtigt. Der Beitrag einzelner mikrobieller Gruppen zu P-(Im)mobilisierung, Reduktion von P-Austrägen und Recycling von P aus mikrobieller Nekromasse (Pnecro) wird untersucht und zur P-Verfügbarkeit und Speziierung in Waldböden in Beziehung gesetzt. Zusammenfassend ermittelt das Projekt die Bedeutung von mikrobieller Bio- und Necromasse als temporärer P-Speicher in Waldökosystemen bei unterschiedlicher P-Verfügbarkeit und Speziierung. Dieser Einblick in die räumliche und saisonale Dynamik von P in mikrobieller Bio- und Necromasse in Waldböden wird zu einem tieferen Verständnis über die Anpassung von Wäldern an P-Mangel beitragen.

Direct link to Lay Summary Last update: 22.05.2017

Responsible applicant and co-applicants

Employees

Publications

Publication
Root-o-Mat: A novel tool for 2D image processing of root-soil interactions and its application in soil zymography
Tegtmeier Jan, Dippold Michaela A., Kuzyakov Yakov, Spielvogel Sandra, Loeppmann Sebastian (2021), Root-o-Mat: A novel tool for 2D image processing of root-soil interactions and its application in soil zymography, in Soil Biology and Biochemistry, 157, 1-12.
Organic Nutrients Induced Coupled C- and P-Cycling Enzyme Activities During Microbial Growth in Forest Soils
Loeppmann Sebastian, Breidenbach Andreas, Spielvogel Sandra, Dippold Michaela A., Blagodatskaya Evgenia (2020), Organic Nutrients Induced Coupled C- and P-Cycling Enzyme Activities During Microbial Growth in Forest Soils, in Frontiers in Forests and Global Change, 3, 1-14.
Small-scale spatial distribution of phosphorus fractions in soils from silicate parent material with different degree of podzolization
Werner Florian, de la Haye Tilman René, Spielvogel Sandra, Prietzel Jörg (2017), Small-scale spatial distribution of phosphorus fractions in soils from silicate parent material with different degree of podzolization, in Geoderma, 302, 52-65.
Manufacturing of triple-isotopically labeled microbial necromass to track C,N and P cycles in terrestrial ecosystems
Schmidt Marius, Manufacturing of triple-isotopically labeled microbial necromass to track C,N and P cycles in terrestrial ecosystems, in applied soil ecology.

Abstract

Soil microbial necromass as an essential phosphorus reservoir in forest nutrition(NecroPool)Forest ecosystems successfully meet the challenge of low phosphorous (P) supply by exploitingminimally accessible inorganic and organic P forms and retaining P within ecosystems.Microorganisms efficiently mobilize plant inaccessible P but also compete with plants for P.Although microbial bio- and necromass can account for greater than 10% of total soil P, theyrarely were considered as primary P contributors to forest P nutrition. This proposal seeks tounravel the relevance of microbial bio- and necromass as P pools for beech P nutrition bycharacterizing the spatial heterogeneity of P distribution in forest ecosystems and contrasting Pcycling in acquiring versus recycling forest ecosystems. The role of individual microbial groupsin P (im)mobilization, reduction of P losses via leaching and re-mobilization of microbialnecromass P (Pnecro) will be analyzed depending on P availability and speciation in forest soils.Immobilization of rhizodeposit P and soil solution phosphate in microbial biomass will bequantified in mesocosms by labeling of soils with KH233PO4 and plants via the wick method.After simulating rainfall events, dissolved organic P and colloidal discharge will be quantifiedand characterized. Microbial P retention and microbial groups accounting for P immobilizationwill be determined by chloroform fumigation extraction (33P-CFE) and 33P phospholipid fatty acid(33P-PLFA) analysis. To determine sources of Pnecro, microbial P formation from low available Psources (33P apatite, Fe-33P-phosphate and 33P plant residues) will be targeted in a subsequentincubation experiment with 33P-CFE and 33P-PLFA analysis. Microbial dilution will revealfunctional redundancy and specialization within microbial communities. Following identificationof Pnecro sources, their functions as an intermediate P reservoir for forest nutrition will beassessed by application of 33P-labelled microbial necromass. A seasonally harvested rhizotronexperiment with heterogeneously distributed Pnecro will enable visualization of P re-mobilizationin beech rhizosphere by 33P imaging and phosphatase zymography. T-shaped mesocosms willallow quantitative determination of Pnecro contribution to beech nutrition with increasing distanceto the stem, especially considering ectomycorrhiza as an alternative Pnecro uptake pathway.Within the central P x N application experiment, PLFA, CFE and phosphatase activity analyzedat increasing distance to the stem will allow transferring these results on the role of Pnecro tosingle tree influence circles at the field scale.Consequently, functions of microbial necromass as an intermediate P reservoir and its role inforest P nutrition will be assessed within the proposed project considering sites of contrasting Pavailability and speciation. Understanding spatial and seasonal dynamics of microbialnecromass P in forest soils will fundamentally enhance our understanding of forest ecosystems’capability to face low P supply.
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