Role of Mycorrhizal Symbiosis in Mineral Weathering and Nutrient Mining from Soil Parent Material

Mineral weathering plays an important role in soil formation, long-term plant nutrition, and the global carbon cycle. The dissolution rate of most soil minerals is extremely slow. Nearly 100. years ago it was proposed that plants actively mine for nutrients locked in soil minerals. In more recent times the role of plant-associated mycorrhizal fungi has been emphasized. In this chapter we critically review the current knowledge on "mycorrhizal weathering." Laboratory-scale experiments demonstrate the potential of mycorrhizal fungi to actively colonize and dissolve specific mineral grains. However, field observations and geochemical modeling suggest that the contribution of mycorrhizal weathering to total weathering is minor compared with the contribution of other soil processes such as weathering agents generated through decomposition, rain water, and plant growth.