Organic and Biofertilizer Interventions in Iron Mine Spoil for Nutrient Fortification with Facilitation of Microbial Exoenzyme Activity and Plant Growth

Open cast iron ore mining generates considerable volume of spoil which is nutrient deficient and therefore does not support microbial and plant growth. Post mining landscape restoration needs nutrient enrichment of the spoil for revegetation. This study reports the effects of suitable organic and biofertilizer amendments on the chemical characteristics, bacterial-fungal load, activities of the exoenzymes, invertase, amylase, cellulase, protease and dehydrogenase along with growth of three subtropical plant species, Cassia tora, Artocarpus heterophyllus, and Pistacia vera in iron mine spoil amended with farm yard manure, poultry manure and Rhizobium biofertilizer in three suitable treatment combinations. All the treatments indicated significantly higher pH, electrical conductivity, organic carbon, nitrogen, phosphorous, and potassium levels with microbial population and exoenzyme activities relative to control over an experimental period of 180 days. Plants grown in treated spoils indicated significantly higher biomass, shoot length, leaf area index and total leaf chlorophyll. The study thus indicated that reclamation of iron mine spoil could be achieved with suitable organic and biofertilizer amendments for subsequent revegetation.