Role of Microbial Inoculants on Growth and Establishment of Plantation and Natural Regeneration in Limestone Mined Spoils

In a soil conditions like limestone mined spoils which has low soil nutrients level with poor nutrient cycling capacity; application of selected microbes as inoculants may be helpful in the establishment of plants in nutrient poor mined spoils. Pongamia pinnata grown on limestone mined over burden dump were supplemented with different microbial and inorganic fertilizer. Plants inoculated with microbial consortia including arbuscular mycorrhizal fungi, Azospirillum sp., Azotobacter sp. and Pseudomonas fluorescens displayed successful establishment and remarkable growth after two years of inoculation. Analysis of different natural successions on natural and artificial substrates suggests that one of the important factors limiting the rate of development is the process of immigration of flora. Application of microbial inoculants ensure the establishment of nutrient supply, soil development which attracts immigration of surrounding species, accelerates natural regeneration process and ultimately a self sustained system on mined spoils is developed.