Methods of increasing the amount of iron (Fe) and potassium (K) available in soil to plants residing in the soil. A composition comprising at least one microorganism capable of oxidizing Fe(II) bound in at least one phyllosilicate and releasing Fe and K from the at least one phyllosilicate to increase availability of Fe and K to plants in soil treated with the composition relative to plants in untreated soil. Compositions and microorganisms capable of oxidizing Fe(II) and K are disclosed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with government support under DE-AC05-76RL01830 and DE-SC0001180 awarded by the U.S. Department of Energy. The government has certain rights in the invention.