Total and extractable soil selenium contents variation within and across the parent materials
By: Muhammad Imran, Mohammad Saleem Akhtar, Khalid Saifullah Khan, Azeem Khalid, Ayaz Mehmood, Shah Rukh, Guljana Nazeer, Rabia Manzoor
Key Words: Multiple regression equation, Parent materials, Extractable selenium, Soil properties, Total selenium.
J. Bio. Env. Sci. 9(4), 175-186, October 2016.
Selenium is an essential trace element for humans and animals by affecting them through its toxicity and deficiency. Selenium contents in soils depend on the source of parent material the soils are derived from. Total soil selenium as well as phosphate-buffer extractable selenium varied with type of parent material and weathering stage. Three replicated soil profiles at three different weathering stages (i.e. least weathered, moderately weathered and relatively more weathered) were sampled at genetic horizons level from alluvium, loess, sandstone and shale parent materials. Total selenium varied between 270 to 7050 µg kg-1, and phosphate buffer extractable selenium ranged from 25 to 90 µg kg-1 soil in the dataset. Total and phosphate-buffer extractable selenium distribution changed differently with soil genesis in each parent material. In shale and loess soils total selenium increased toward the surface in relatively more developed soils whereas in alluvium and sandstone soils weathering effect was negligible. The mean phosphate-buffer extractable selenium was significantly high in the shale derived soils followed by the loess, alluvium and sandstone. Multiple regression equation predict that crystalline iron, total selenium, Ald, and cation exchange capacity are the main controlling factors for phosphate buffer extractable selenium.