Desodification from calcareous saline sodic soil through phytoremediation with Phragmitesaustralis (Cav.) Trin. ex Steud. and gypsum

ABSTRACT

The reclamation of saline sodic soils requires sodium removal and the phytoremediation is one of the proven low-cost, low-risk technologies for reclaiming such soils. However, the role of Phragmites australis in reclaiming saline sodic soils has not been evaluated extensively. The comparative reclaiming role of P. australis and gypsum was evaluated in a column experiment on a sandy clay saline sodic soil with EC_e 74.7 dS m⁻¹, sodium adsorption ratio (SAR) 63.2, Na⁺ 361 g kg⁻¹, and pH 8.46. The gypsum at 100% soil requirement, planting common reed (P. australis) alone, P. australis + gypsum at 50% soil gypsum requirements, and leaching (control without plant and gypsum) were four treatments applied. After 11 weeks of incubation, the results showed that all treatments including the control significantly reduced pH, EC, exchangeable Na⁺, and SAR from the initial values, the control being with least results. The gypsum and P. australis + gypsum were highly effective in salinity (EC_e) reduction, while sodicity (SAR) and Na⁺ reductions were significantly higher in P. australis + gypsum treatment. The reclamation efficiency in terms of Na⁺ (83.4%) and SAR (86.8%) reduction was the highest in P. australis + gypsum. It is concluded that phytoremediation is an effective tool to reclaim saline sodic soil.

KEYWORDS:

• desodification
• reclamation efficiency
• saline sodic soil
• phytoremediation
• gypsum
• Phragmites australis