Comparison of Clay Mineralogy and Micromorphological Image Analysis of Anaerobic and Aerobic Soils in the North of Iran

• Published in: Eurasian soil science 2023-10, Vol.56 (10), p.1463-1478
• Main Authors: Raheb, A. R., Heidari, A.
• Format: Article
• Language: English
• Subjects: Aeration; Agricultural land; Anaerobic conditions; Anoxic conditions; Chemical analysis; Citrus fruits; Clay; Clay minerals; Correlation; Cultivation; Earth and Environmental Science; Earth Sciences; Fruit cultivation; Fruits; Geotechnical Engineering & Applied Earth Sciences; Groundwater; Groundwater levels; Groundwater table; Image analysis; Image processing; Iron oxides; Kiwifruit; Land use; Manganese; Mineralogy; Mineralogy and Micromorphology of Soils; Oxidation; Puddling; Rice fields; Smectite; Smectites; Soil; Soil analysis; Soils; Statistical analysis; Statistical methods; Vermiculite; Vermiculites; Water table; Water, Underground
• ISSN: 1064-2293; 1556-195X
• DOI: 10.1134/S1064229323600355

This study aimed to compare the capability of image analysis in recognition and measuring different chemical forms of iron existing in the thin sections. The pedogenic forms of iron in three adjacent agricultural land uses, including paddy (Hydragric Anthrosols), citrus (Arenosols), and kiwi fruit (Cambisols) cultivated soils were determined and compared using the image and chemical analyses methods. Stepwise removal of iron oxyhydroxides from the soil thin sections was carried out using chemical iron oxide extractors, followed by photographing after each treatment using the Olympus AnalySIS software. The results revealed that the Hydragric Anthrosols contain higher amounts of DTPA-extractable (available) Fe and Mn and low P and K contents than the citrus and kiwi fruit land uses. We attributed these to anaerobic conditions caused by artificial anthraquic conditions at the surface and the high ground water table. Mineralogical analyses results indicated that smectite was the most dominant clay mineral in the Hydragric Anthrosols, while in the well-drained Arenosols and Cambisols, vermiculite is the dominant mineral. Also, the micromorphological results showed that after the construction of kiwi orchards in the former paddy fields, the pore volume and redoximorphic features increased, due to better aeration conditions and the cessation of puddling. The use of image analysis techniques helped us better understand the repeated oxidation and reduction processes and quantify the redoximorphic features of the soil. Statistical analysis showed that although there is no significant correlation ( R 2 = 0.0321 in Fe t , 0.0353 in Fe ox , and 0.2141 in Fe cd ) between the amounts of iron forms obtained from image analysis and chemical techniques. The citrate dithionate extractable form shows a better correlation compared to the total and oxalate extractable forms.