African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6576

Full Length Research Paper

Soil salinity in irrigated fields used for urban agriculture under a semi-arid environment of South Africa

S. A. Materechera
Faculty of Agriculture, Science and Technology, North West University (Mafikeng Campus), P/B X2046, Mmabatho, 2735, South Africa
Email: [email protected]

  •  Accepted: 22 July 2011
  •  Published: 18 August 2011

Abstract

The study quantified the salinity in profiles of urban agriculture soils irrigated using sprinkler, basin and drip methods for 15 years compared with rainfed conditions. The ANOVA showed significant influence (p < 0.05) of both irrigation methods and soil depth on the amount of soluble salts, pH and electrical conductivity (ECe) of the soils. Irrigation methods significantly increased (p < 0.05) the salt concentration (mg/kg) within the profile compared to the control for Ca2+ (792 vs 464), Mg2+ (398 vs 196), K+ (274 vs 164), Na+ (19.3 vs 9.8), pH (7.13 vs 6.3) and ECe (22.1 vs 7.9 dS/m). Except for Na, the concentrations of Ca, Mg and K were higher in the top than subsoil layers while pH and ECe were not significantly different. Basin irrigation had consistently accumulated highest amounts of Ca, Mg, K and Na followed by drip and sprinkler method. The pattern for pH and EC was basin > drip > sprinkler > control. Sprinkler irrigation was the only method which showed increased pH and ECe at 10 to 20 cm compared to 0 to 10 cm depth. It was concluded that irrigation was increasing salinity in the soils and points to the need for adherence to sound irrigation water management practices especially appropriate irrigation scheduling.

 

Key words:    Crop production, irrigation water quality, salt accumulation, urban agriculture, root zone salinity, semi arid areas.