Framlög af járnmagni plantna til jarðvegs - verkefni lokið

Fréttatilkynning verkefnisstjóra


Plants play an integral role in nutrient cycling in soils. However, the forms of iron and other metals that are returned to the soil in plant litter or by vegetation ash after wildfire are not well known.

This study investigated plant-based inputs of iron to soils by determining the amount and bioavailability of iron in plant litter and ashes using a series of chemical extractions to identify distinct chemical iron fractions in organic matter. Electron microscopy and magnetic properties were also employed to support the geochemical analysis. Key
conclusions from this work include:
1. Total extractable Fe and magnetic signal in plant litter vary widely by plant type.
2. A significant amount of iron in plant litter and subsequent ash is derived from inorganic particulate matter embedded in plant surfaces. Thermal transformation of this particulate matter strongly influences the Fe phase composition of the ash.
3. Plant ash contains a significant amount of labile iron, suggesting that Fe bioavailability should decrease only modestly after burning, and may even increase.
4. So- called “enhanced” mass-specific magnetic susceptibility in ash-rich soil surface layers largely reflects the loss of mass during burning.
5. There is probably no unique “signature” of plant ash or charcoal. Magnetic properties
and Fe fractions will vary with fire intensity, the local environmental, and plant type.

The results will be used to identify past fire incidence and better understand the role of
wildfire on metal nutrient cycling in soils. Part of the project results have been reported in a
published manuscript and several conference presentations, and two additional manuscripts
are forthcoming.

Heiti verkefnis: Framlög af járnmagni plantna til jarðvegs/ Quantifying plant contributions of iron to soils
Verkefnisstjóri: Jessica L Till, Háskóla Íslands
Tegund styrks: Nýdoktorsstyrkur
Styrktímabil: 2017-2019
Fjárhæð styrks kr. 25.936.000
Tilvísunarnúmer Rannís: 173743

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