von Lützow, M; Kögel-Knabner, I; Ekschmitt, K; Flessa, H; Guggenberger, G; Matzner, E; Marschner, B: SOM fractionation methods: Relevance to functional pools and to stabilization mechanisms, Soil Biology Biochemistry, 39, 2183-2207 (2007), doi:10.1016/j.soilbio.2007.03.007
Abstract:
Soil organic matter (SOM) consists of various functional pools that are stabilized by specific mechanisms and have certain turnover rates. For the development of mechanistic models that predict changes in SOM storage, these pools have to be quantified and characterized. In the past, numerous fractionation schemes have been developed to separate and analyse such SOM fractions. In this review, the SOM fractions obtained with such operational fractionation procedures are described in terms of their pool sizes, chemical properties, and turnover rates. The main objective of this review is to evaluate these operationally defined fractions with respect to their suitability to describe functional SOM pools that could be used to parameterize SOM turnover models. Fractionation procedures include (1) physical separation of SOM into aggregate, particle size, and density fractions and fractions according to their magnetic susceptibility, and (2) various wet chemical procedures that fractionate SOM according to solubility, hydrolysability, and resistance to oxidation or by destruction of the mineral phase. Furthermore, combinations of fractionation methods are evaluated. The active SOM pool with turnover rates <10 years may best be represented by the soil microbial biomass and the light fraction (<1.6–2 g cm−3) obtained by density fractionation (if black carbon contents are considered). Most chemical and physical fractionations as well as combinations of methods yield SOM fractions that are not homogeneous in terms of turnover rates. It has proven to be particularly difficult to isolate functional fractions that represent the passive model pools in which the majority of soil SOM is stabilized. The available fractionation methods do not correspond to specific stabilization mechanisms and hence do not describe functional SOM pools. Another problem is that comprehensive data for turnover rates and data for whole soil profiles are only now becoming available, especially for new fractionation methods. Such information as well as the use of specific markers and compound-specific isotope analysis may be important for future differentiation and evaluation of functional SOM fractions. Keywords: Physical soil fractionation; Wet chemical fractionation; Mean residence time; Turnover time; Recalcitrance; Spatial inaccessibility; Organo–mineral interactions; Conceptual model pools
Aktuelle Termine


BayCEER-Kolloquium:
Do. 12.12.2019
Iron, sulfur and a pinch of antimony - new perspectives on secondary mineral pathways and metalloid mobility
Geographisches Kolloquium:
Di. 10.12.2019
Intensify or diversify? How agriculture affects biodiversity and ecosystem processes in European farmland
Di. 17.12.2019
The meat of the Anthropocene: Food, capital and the globalisation of industrialised animal killing
Ökologisch-Botanischer Garten:
So. 05.01.2020
Auf ins Neue! Winterspaziergang im ÖBG
So. 05.01.2020
Konzert: Musikalischer Jahresbeginn mit den Rockin`Dinos
BayCEER Blog
24.05.2019
Stoichiometric controls of C and N cycling
07.05.2019
Flying halfway across the globe to dig in the dirt – a research stay in Bloomington, USA
07.05.2019
EGU – interesting research and free coffee
16.04.2019
Picky carnivorous plants?
RSS Blog als RSS Feed
Wetter Versuchsflächen
Luftdruck (356m): 959.5 hPa
Lufttemperatur: 8.3 °C
Niederschlag: 1.9 mm/24h
Sonnenschein: 5 h/d
Wind (Höhe 17m): 14.1 km/h
Wind (Max.): 28.4 km/h
Windrichtung: SW

...mehr
Niederschlag: 0.7 mm/24h
Sonnenschein: <1 h/d

...mehr
Diese Webseite verwendet Cookies. weitere Informationen