Changes in the microbial community and physico‐chemical characteristics of topsoils stockpiled during opencast mining

Abstract

Abstract. Experiments on the effects of stockpiling soil on an opencast coal mine in Derbyshire showed that there were significant changes in the microbial community. Numbers of aerobic bacteria in stored soils ranged from 0.5 to 12.8 ± 10 7 colony‐forming‐units (CFU)g ‐1 with the smallest values being in the deepest parts of the oldest stores, whereas an adjacent undisturbed soil contained 6.6 ± 10 7 CFU g ‐1 . There was a greater effect on the numbers of fungal spores, which ranged from 0.1 to 6.7 ± 10 5 CFU g ‐1 soil, all less than the 10 ± 10 5 CFU g ‐1 recorded for the undisturbed control soil. The number of fungal spores in the deepest part of the older soil stores was only 1/100 of the number in the undisturbed soil. This was mirrored by the biomass values, as determined by adenosine triphosphate (ATP) assay. Values of ATP ranged from 0.38 to 13.13 nmol g ‐1 as compared to 5.8 nmol g ‐1 in the undisturbed soil. All three of these microbiological properties decreased in value with both age and depth of storage. Neither anaerobic nor spore‐forming bacterial numbers were greatly affected by storage. The pH values tended toward neutrality in the deeper parts of the soil stores, and there was less organic matter in the older stores.