Plants and redox potential: iron-rich clay minerals as redox active compounds in soils

Redox potential is an important soil property for plant growth, nutrition and development that is still not widely considered by agronomists, even though many studies have found that cultivated soils tend to oxidise over time and the soil redox potential becomes non-optimal for plant development. The objective of this literature review is to identify a type of material that can be used as amendment and allowed to regulate soil redox potential. An extensive study was conducted to investigate the influence of redox potential on soils and plants. Then, a focus on clay minerals that can be used for crop management as a regulator of redox potential in soils was realized. Soil redox potential has been shown to have a strong impact on the growth and development of microorganisms (pathogenic, beneficial or neutral), on nutrient solubility and availability, on the solubility and toxicity of many pollutants (heavy metals, organics) and on the degradation of organic matter. Clay minerals could be used to regulate the soil redox potential. Indeed, some clay minerals have redox properties due to their iron-rich composition, that can potentially regulate the redox potential of soils. This review has shown that the study of the redox potential of soils is essential in soil management due to its strong influence on plant growth and development. In addition, iron-rich clay minerals appear to be very attractive materials for applications as a regulator of the redox potential of soils.