Yellowing of a red south african kandiudult, studied by means of mössbauer spectroscopy

• Main Authors: Van Ranst, E., Padmanabhan, E., Vandenberghe, R.E., De Grave, E., Mees, F.
• Format: Article
• Published: Lippincott Williams and Wilkins 2016
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959135815&doi=10.1097%2fSS.0000000000000143&partnerID=40&md5=dbd1e2c815bc8e90df2e4527e33a9edd; http://eprints.utp.edu.my/31032/
• Institution: Universiti Teknologi Petronas

An Acrudoxic Kandiudult soil profile from Farmhill, KwaZulu-Natal Province, South Africa, was analyzed by Mössbauer spectroscopy as an example of a red soil with yellowish surface horizons, a common sequence for which iron oxide characteristics are only poorly documented. In the red lower part of the profile (62+ cm), the Fe oxide fraction consists of hematite and well-crystallized pure goethite. In the yellowish upper part (0-62 cm), the relative hematite content is lower, goethite shows a high degree of Al-for-Fe substitution, and ferrihydrite is present. Processes found to have affected the Fe oxide fraction are hematite dissolution, partial leaching, goethite precipitation with a high degree of Al incorporation, and ferrihydrite formation in conditions with a high organic matter content; the so-called DOM (dissolved organic matter) ferrihydrites. © 2016 Wolters Kluwer Health, Inc.