Restoration of soil function requires plants, arbuscular mycorrhizal fungi and organic matter

摘要

Insufficient topsoil often limits the establishment of native plants during restoration of mine sites. We address this problem by developing a suitable "capping topsoil" from coal mine overburden (spoil) for use at an open cut coal mine in Hunter Valley, NSW, Australia. The hierarchical model of aggregation served as the basis for the experiment. Plants with or without arbuscular mycorrhizal (AM) fungi were grown in 0, 6, 12 or 18% w/w of compost in spoil and placed in elongated tubes. Non-mycorrhizal plants in 18% compost amended spoil maximised water retention. Below 18% compost the presence of mycorrhizal fungi on roots of plants led to maximum water retention. A plateau in water retention was reached with the addition of between 6 and 12% compost in the mycorrhizal treatments, which is equivalent to 1.75 - 3.5% organic carbon in soil. Plants, AM fungi and organic matter were required to convert a massive mine spoil to a suitable "capping topsoil".