Influence of organic amendments and arbuscular mycorrhizal inoculation on plant growth and nutrient uptake in iron ore mine spoils

Abstract

Trema orientalis L. Blume is able to grow on nutrient-deficient soils and known to be a metal tolerant plant species displaying potential for use in mine restoration programmes. However, reclamation strategies would depend on the plant species used, and physico-chemical status of the spoil that often limits plant growth. This study was directed to determine the efficiency of arbuscular mycorrhizal (AM) species Rhizophagus irregularis and soil organic amendments (farm yard manure [FYM] and vermicompost [VC]), in enhancing growth and nutrient acquisition of T. orientalis in iron ore mine spoil (MS). A pot experiment was conducted using five treatments viz., AM, FYM, FYM and AM, VC, and VC and AM, with pure spoil as the control. Growth parameters, foliar nutrient concentrations and percentage AM root colonisation were determined at the end of 12?months. Addition of FYM and VC altered the chemical properties of spoil, increased pH and macro- and micro-nutrient levels and enhanced plant growth. Growth of T. orientalis was significantly increased by both organic amendments and by AM inoculation over control. AM colonisation increased plant survival in pure spoil and enhanced growth in both pure and amended spoil. High AM colonisation and plant dependency were recorded in pure MS and lower levels in amended spoil. AM colonisation plays a significant role in survival of T. orientalis in hostile iron ore MS environment. T. orientalis transplant success on iron ore mine sites would be greatly increased with VC and R. irregularis amendment.