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Lookup NU author(s): Professor David ManningORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2022 Cambridge University Press. All rights reserved. Mineral reactions in soils demonstrably take place on a human timescale. The weathering of silicate 'rock-forming' minerals releases nutrients that are essential for plant growth, including silica. This process consumes CO2 that is ultimately derived from the atmosphere, through enhanced rock weathering. From a human perspective, the weathering process has two beneficial functions - crop nutrition and climate mitigation, through removal of atmospheric CO2. By considering these as a coupled process, the release of silica during weathering can be matched to what is taken from the soil by a crop, for example wheat. A simple analysis shows that the amount of silica that accumulates in wheat during a 4 month growing period is readily released by the weathering of pyroxene and plagioclase, minerals that commonly occur in basic igneous rocks. In contrast, the dissolution rate for quartz is so low that it cannot supply the silica taken up by the crop, and is inert. Similarly, dissolution of clay minerals releases sufficient silica for plant uptake. Rapid weathering of silicate minerals within soils is evident from images of surfaces of grains exposed in soils for periods of 10-100 years. The evidence for silicate rock weathering as part of the soil system that sustains humanity is provided by the vegetation that we see around us.
Author(s): Manning DAC
Publication type: Review
Publication status: Published
Journal: Clay Minerals
Year: 2022
Volume: 57
Issue: 1
Pages: 31-40
Print publication date: 01/03/2022
Online publication date: 08/08/2022
Acceptance date: 17/07/2022
ISSN (print): 0009-8558
ISSN (electronic): 1471-8030
Publisher: Cambridge University Press
URL: https://doi.org/10.1180/clm.2022.17
DOI: 10.1180/clm.2022.17
