Arbuscular Mycorrhizal Technology in Reclamation and Revegetation of Coal Mine Spoils under Various Revegetation Models

Akhilesh Kumar

doi:10.4236/engineering.2010.29088

Abstract

Reclamation and revegetation of a coal mine spoils with various revegetation models utilizing the mycorrhizal technology were studied. The models with different combination of plant species were designed to test the hypothesis of speedy revegetation. Root colonization and spore density of arbuscular mycorrhizae (AM) were lowest in plants seeded directly on slopes of the overburden (coal mine dump). At flat surfaces, the mycorrhizal colonization in plant species was higher than that observed at slopes. In other revegetation models, i.e., tree monoculture, tree monoculture + crop species (agroforestry), and two strata plantations (combination of different plant species), maximum AM colonization was recorded for tree species grown along with crop species. This was followed by two strata plantations and tree monoculture. In two strata plantations three categories of AM associations were recognized: 1) every plant in the combination, possessed high mycorrhizal association, 2) only one plant in the combination possessed high mycorrhizal association, and 3) none of the plants in the combination possessed high mycorrhizal association. Azadirachta indica, Pongamia pinnata, Leucaena leucocephala and Acacia catechu were most effective in catching mycorrhizae, and can be used as the effective tool in rehabilitation of the degraded ecosystems.

Highlights

AM fungi form the fundamental linkage between the biotic and abiotic components of the ecosystem in addition to their being the primary colonizers of coal mine spoils [1,2]
Reclamation and revegetation of a coal mine spoils with various revegetation models utilizing the mycorrhizal technology were studied
I.e., tree monoculture, tree monoculture + crop species, and two strata plantations, maximum AM colonization was recorded for tree species grown along with crop species

Summary

Introduction

AM fungi form the fundamental linkage between the biotic and abiotic components of the ecosystem in addition to their being the primary colonizers of coal mine spoils [1,2]. The contribution of AM fungi to soil aggregate formation can be grouped into three categories according to Miller and Jastrow [7]: These are: 1) growth of external AM hyphae in the soil matrix to create the skeleton that holds primarily the soil particles (i.e. sand, silt and clays) together via physical entanglement, 2) creation of conditions by roots and external hyphae conducive to formation of microaggregates whereby mineral particles and organic debris are held and cemented together by various physico-chemical events involving binding agents like the persistent gums and glues in the root exudates, the soil microbes and mycorrhizal hyphae in particular contribute hydrophobic glycoprotein glomalin [8], and 3) enmeshment of microaggregates and smaller macroaggregates by external hyphae and roots to form the macroaggregates that can be further stabilized by intermicoraggregate and intermacroaggregate cementation by polysaccharides and other organics from microorganisms and plant roots These three processes operate simultaneously because of dynamic

Methods

Results

Conclusion