Bioaccessibility and residence time of phosphorous in forest subsoils

Break neu

Plants may take up between 10 and 80 % of their P demand from subsoils, but the P forms, their accessibility and particularly the residence time of oxygen in phosphates of forest subsoils are currently hardly understood. This project aims at finally testing the hypothesis that at increased P deficiency in the surface soil there is an increased utilization of subsoil P. As a basis for testing this hypothesis, we aim at (i) quantifying the P stocks, binding forms, and delta18O signature of phosphates in different subsoil compartments of the central field sites, (ii) tracking the effect of plant roots on P properties in the subsoil, (iii) elucidating the accessibility of subsoil P for delta18O exchange reactions; (iv) contributing to the understanding of the residence form of subsoil phosphates on the basis of position-specific exchange kinetics of stable oxygen isotopes in labelled inorganic P residues, and (v) relating this information to the P uptake by subsoil root systems. The P forms and concentrations are characterized by sequential P extraction procedures, XANES, high-resolution NanoSims element mapping, and liquid-state 31P-NMR spectroscopy. Isotope analyses and exchange studies are performed using a combination of Raman and isotope-ratio mass spectrometry. Quantum chemical calculations will help to interpret the spectroscopic measurements.




Principal investigators: 

Prof. Dr. Wulf Amelung
University of Bonn, INRES Soil Science
Nussallee 13
53115 Bonn
Tel.: (+49)  229 73 2780

Dr. Hans Lewandowski
Forschungszentrum Jülich GmbH
Wilhelm Jonen-Str.
52428 Jülich
Tel.: (+49) 2461 61 4047

Postdoctoral scientists:

Dr. Andrej Rodionov
University of Bonn, INRES Soil Science
Nussallee 13
53115 Bonn
Tel.: (+49) 228 73 2777

Study sites


Bad Brückenau (BBR)

Conventwald (CON)

Lüss (LUE)

Mitterfels (MIT)

Vessertal (VES)

Tuttlingen (TUT)

Funded by

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