1. oxide generally at pH > 8.0
Manganese Cycle
Fertilizer
and
Manure
Mn2+ exchangeable
(adsorbed cation or
in solution)
oxidation
reduction
reactions
Biological oxidation
Bacteria - Arthrobacter, Bacillus
Fungi - Cladisporium, Curvularia
weathering
> pH 7.0
Organic
complexes
(predominantly soil
organic matter)
Precipitated
Mn oxides
Plant
uptake
residue
Parent
material
Mn3+ as Mn2O3,
unstable oxide
Mn4+ as MnO2, very inert
oxide generally at pH > 8.0
Foliar sprays
(usually MnSO4)
Deficiencies pH>7.0, <20 ppm
Toxicities pH<5.5, >500 ppm
Optimum availability at pH 6.2 to 6.4
diffusion