Journal of
Soil Science and Environmental Management

  • Abbreviation: J. Soil Sci. Environ. Manage.
  • Language: English
  • ISSN: 2141-2391
  • DOI: 10.5897/JSSEM
  • Start Year: 2010
  • Published Articles: 311

Full Length Research Paper

Sulphate sorption and desorption characteristics of selected Malawi soils

J. H. A. Maida*
  • J. H. A. Maida*
  • Department of Crop and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, P.O. Box 219, Lilongwe. Malawi.
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P. C. Nalivata
  • P. C. Nalivata
  • Department of Crop and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, P.O. Box 219, Lilongwe. Malawi.
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  •  Received: 11 February 2016
  •  Accepted: 14 April 2016
  •  Published: 30 September 2016

Abstract

The soils selected for this study represented major soil types in Malawi. They exhibited a wide range of physical and chemical properties. Their pH values ranged from 4.7 to 6.7 and their contents of clay fraction (<0.002 mm) ranged from 170 to 500 g kg-1, organic matter from 6.7 to 39.3 g kg-1, free Fe2O3 from 18.9 to 44.7 g kg-1, and free Al2O3 from 17.8 to 45.6 g kg-1. The soils varied widely in their SO4 sorption behaviour. Soil pH was negatively and significantly correlated (P<0.05) with the bonding energy (k) of SO4 by the soil, Langmuir sulphate sorption maximum (b) and maximum buffering capacity (MBC). Soil organic matter was positively and significantly related with k, b and MBC at the same level of significance (P<0.05). Free Al2O3 and Fe2O3 were positively and significantly related (P<0.001) with b and MBC. Free Fe2O3 and Al2O3 were positively and significantly correlated with k at P<0.01 and P<0.001 respectively. About 90 and 91% of the total variations in the sulphate sorption maxima were accounted for by free Al2O3 and Fe2O3 respectively.

Key words: Sulphate, sorption, desorption, Langmuir, hysteresis, affinity.