Effects of root exudates and humic substances on weathering kinetics |
| |
Authors: | Michael Ochs Ivano Brunner Werner Stumm Bo?ena ?osovi? |
| |
Institution: | 1. Swiss Federal Institute of Technology Zürich (IGW/EAWAG), 8600, Dübendorf, Switzerland 2. Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL), 8903, Birmensdorf, Switzerland 3. Center for Marine Research, Ru?er Bo?kovi? Institute, 41001, Zagreb, Croatia
|
| |
Abstract: | The effect of complex natural organic ligands on the weathering kinetics of aluminum oxide was investigated in laboratory experiments. A peat-derived humic substance and root exudates obtained from ectomycorrhizal (Picea abies — Hebeloma crustuliniforme) and non-mycorrhizal Norway Spruce trees; and γ-Al2O3 were used as a model system. The experimental weathering rates are in accordance with a surface-controlled dissolution mechanism. The effect of the humic material on dissolution rates appears to depend on the degree of protonation of the humic (macro)molecules: we observed dissolution-enhancement or -inhibition at pH 3 and 4, respectively. Ectomycorrhizal exudates proved to be effective weathering agents at pH 4, as opposed to humic material and non-mycorrhizal exudates. Our results suggest that (i) the role of humic materials in mineral weathering and podzolization is different from what is commonly thought, and (ii) mineral weathering rates in the rhizosphere may be higher than in the bulk soil. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|