Re‐establishing life in restored topsoils

Abstract

Surface mining activities and other large civil engineering works often involve the removal, storage and reinstatement of topsoil. Disturbance disrupts normal biological functions within the soil and can markedly change the environment within which soil organisms must exist. This has implications for soil fertility and for the overall ecology of replaced land. A number of studies have investigated the impact of opencast coal mining practices on soil organisms and their capacity for recovery following site reinstatement. The extent and duration of any adverse effect varies from one group of organisms to another according to their vulnerability to damage, their capacity for recovery and their ability to recolonize areas from which they have been eliminated. Three groups of organisms-earthworms, aerobic bacteria and vesicular arbuscular endophytes-are considered, to illustrate their differing responses to soil disturbance and the various factors limiting their early recovery throughout a restored area. Given favourable management, consistent with good general rehabilitative practice, the re-establishment of normal earthworm populations depends entirely on the distribution of an inoculum. For aerobic bacteria adverse physical conditions in reinstated soils are the overriding influence determining levels of activity. For mycorrhizal fungi both soil conditions and the absence of an inoculum may delay recovery, although the evidence in support of this view is inconclusive.

Establishment and Survival of Different Legume and Grass Species and Cultivars at a Limestone Quarry in Greece

“…From this point of view, L. corniculatus, A. desertorum, and the particular cultivars of T. subterraneum and D. glomerata performed better than the others in the semi-arid area of limestone quarry. The initial vegetation cover of these species could create favorable conditions for invasion of native species from the surrounding areas (Scullion, 1992) and/or for reseeding themselves.…”

Effects of composted green waste on soil quality and tree growth on a reclaimed landfill site

“…This may have been due to experimental trees reaching sufficient age to begin leaf litter contribution to the soil, and due to a low density of indigenous soil fauna to mineralise the added OM at the start of the experiment. This trend of increasing SOM, especially in the presence of earthworm activity, is likely to have beneficial outcomes on soil microbial diversity and associated nitrogen mineralisation [33].…”

Condition of rehabilitated coal mines in the Hunter Valley, Australia

“…One of the indicators of successful rehabilitation is the extent of vegetation cover, as this will influence erosion rates and sediment loss and strongly influence people's perception of the aesthetics of the repaired landscape. Although not studied here, re-establishment of soil organisms forms part of successful restoration (Scullion, 1992), as biological activity in soils is also disrupted during the process of mining and rehabilitation. At the three mine sites studied, particular chemical problems of soils tended to be reflected in localised reductions in vegetation cover.…”