『Abstract
　Field-scale observations of two upland soils derived from contrasting granite and basalt bedrocks are presented to hypothesize that redox activity of rhizospheres exerts substantial effects on mineral dissolution and colloidal translocation in many upland soils. Rhizospheres are redox-active microsites and in the absence of O2, oxidation of rhizodeposits can be coupled by reduction of redox-active species such as Fe, a biogenic reduction that leads to Fe translocation and oxidation, accompanied by substantial proton flux. Not only do rhizogenic Fe-C redox cycles demonstrate a process by which the rhizosphere affects an environment well outside the near-root zone, but these redox processes are also hypothesized to be potent weathering systems, such that rhizogenic redox-reactions complement acid- and ligand-promoted reactions as major biogeochemical processes that control crustal weathering. The potential significance of Fe-C redox cycling is underscored by the deep and extensive rooting and mottling of upland subsoils across a wide range of plant communities, lithologies, and soil-moisture and temperature regimes.

Keywords: Rhizospheres; Soil redox; Soil organic matter; Iron; Pedogenic oxides; Soil microsites; Mottling; Redoximorphic features』

Introduction
Materials and methods
　Site descriptions, and sample acquisition and preparation
　Soil chemical and physical properties
　Soil mineralogy by X-ray diffraction and differential scanning calorimetry
　Radiocarbon analysis
　Environmental scanning electron microscopy
　Fatty acid methyl-ester analysis
Results
　Observations of profiles, horizons, and microsites
Discussion
　The hypothesis
Acknowledgments
References