Incorporation of crop residues in the soil results in the more reducing conditions as compared to other post harvest
management practices. Understanding the nature and extent of reducing conditions and impacts of these reducing conditions
on the iron minerals in the paddy soils is the focus of recent research. Two adjacent rice plots with different residue
management practices were selected to measure the redox potentials and pH throughout the rice cultivation period. A
thermodynamic approach, by constructing the pe-pH diagrams, was used to calculate the stability of iron minerals:
Throughout the rice cultivation period a large variability between pe and pH values was observed such that -6 < pe < 11 and
6.8 < pH < 8.4. It was found that before flooding, in both paddy fields, all the iron should be stable in the form of Fe3+
(system was oversaturated with respect to Hematite, Goethite, Lepidocrocite and Fougerite) and at the end of the rice
cultivation period all the iron should be stable in the form of the Fe2+ (system was under-saturated with respect to all
mentioned iron minerals). The results also showed that incorporation of rice residues and rhizospheric activity have very
determinant role in the dissolution of different iron minerals.
Muhammad Farrakh Nawaz, Guilhem Bourrié, Sadaf Gul, Fabienne Trolard, Jean-Claude Mouret, Muhammad Ayyoub Tanvir. (2014) Effects Of Post Harvest Management Practices On The Stability Of Iron Minerals In Rice Culture, , Volume-51, Issue-4.
