Reforestation of Bauxite mine spoils with Eucalyptus tereticornis Sm. seedlings inoculated with Arbuscular mycorrhizal fungi

Abstract

Open cast mining for bauxite at Yercaud hills (India) resulted in degradation of forest ecosystem and production of large quantities of waste rocks (called mine spoils). To ameliorate mine spoils, topsoil is used to spread over before the planting of tree species, conventional method as the topsoil has a good structure, water holding capacity and beneficial microbes like Arbuscular Mycorrhizal (AM) fungi essential for plant growth. However, the use of top soil is expensive and in this study bauxite mine spoils were reforestated with AM fungi instead of it. The beneficial microbes AM fungi (Glomus aggregatum Schenck & Smith, G. fasciculatum (Thatcher) Gerd. & Trappe emend. Walker & Koske, G. geosporum (Nicol. & Gerd.) Walker) were isolated, cultured and inoculated into the seedlings ofEucalyptus tereticornis Sm. and grown in bauxite mine spoils as potting medium under nursery conditions. Then, the biomass improved seedlings of E. tereticornis with inoculation of AM fungi were directly transplanted at bauxite mine spoils. After transplantation of the seedlings at bauxite mine spoils, the growth and survival rate were monitored for two years. The AM fungi inoculated seedlings ofE. tereticornis showed 95% survival over the control seedlings and their growth was also significantly higher. Tissue nutrients (N, P, K) were also found higher in AM fungi inoculated E. tereticornis than un inoculated control seedlings.