Description: Das Projekt "Vertical partitioning and sources of CO2 production and effects of temperature, oxygen and root location within the soil profile on C turnover" wird vom Umweltbundesamt gefördert und von Johann Heinrich von Thünen-Institut, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Institut für Agrarrelevante Klimaforschung durchgeführt. For surface soils, the mechanisms controlling soil organic C turnover have been thoroughly investigated. The database on subsoil C dynamics, however, is scarce, although greater than 50 percent of SOC stocks are stored in deeper soil horizons. The transfer of results obtained from surface soil studies to deeper soil horizons is limited, because soil organic matter (SOM) in deeper soil layers is exposed to contrasting environmental conditions (e.g. more constant temperature and moisture regime, higher CO2 and lower O2 concentrations, increasing N and P limitation to C mineralization with soil depth) and differs in composition compared to SOM of the surface layer, which in turn entails differences in its decomposition. For a quantitative analysis of subsoil SOC dynamics, it is necessary to trace the origins of the soil organic compounds and the pathways of their transformations. Since SOM is composed of various C pools which turn over on different time scales, from hours to millennia, bulk measurements do not reflect the response of specific pools to both transient and long-term change and may significantly underestimate CO2 fluxes. More detailed information can be gained from the fractionation of subsoil SOM into different functional pools in combination with the use of stable and radioactive isotopes. Additionally, soil-respired CO2 isotopic signatures can be used to understand the role of environmental factors on the rate of SOM decomposition and the magnitude and source of CO2 fluxes. The aims of this study are to (i) determine CO2 production and subsoil C mineralization in situ, (ii) investigate the vertical distribution and origin of CO2 in the soil profile using 14CO2 and 13CO2 analyses in the Grinderwald, and to (iii) determine the effect of environmental controls (temperature, oxygen) on subsoil C turnover. We hypothesize that in-situ CO2 production in subsoils is mainly controlled by root distribution and activity and that CO2 produced in deeper soil depth derives to a large part from the mineralization of fresh root derived C inputs. Further, we hypothesize that a large part of the subsoil C is potentially degradable, but is mineralized slower compared with the surface soil due to possible temperature or oxygen limitation.
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Tierhaltungsanlage ? Humus ? Sauerstoff ? Umweltauswirkung ? Kohlenstoffarme Wirtschaft ? Bodenkunde ? Kohlendioxid ? Moorboden ? Radionuklid ? Temperatur ? Wirkung ? Pflanzenwurzel ? Organische Verbindung ? Unterboden ? Abbaubarkeit ? Bodenprofil ? Bodenhorizont ? Fraktionierung ? Isotop ? Kontrollmaßnahme ? Mineralisation ? Quantitative Analyse ? Studie ? Verwitterung ? Wertermittlung ? Wirkung ? Messung ? Datenbank ? Produktion ? in situ ? Lagerung ? Ökologischer Faktor ? Radioaktivität ? Speicherung ? Standortbedingung ? Feuchtigkeit ? Boden ? GEBRAUCHT ? Konzentrat ? SPEZIFISCH ? NEU ? STANDORT ? Stall ? OBERFLAECHE ? MECHANISMEN ? TEIL ? Tümpel ? VERANTWORTUNG ? VERBINDUNG ? VERGLEICHEN ? PFAD ? VERSCHIEBUNG ? VERTEILUNG ? Vermehrung ? EINSATZ ? ERGEBNIS ? EINGESCHRAENKT ? KONTROLLE ? SCHICHT ? DAUER ? MISCHUNG ?
Region: Niedersachsen
License: cc-by-nc-nd/4.0
Language: Englisch/English
Time ranges: 2013-01-01 - 2025-03-31
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