Implications of Soil Biodiversity for Sustainable Organic Matter Management - Sustainable Management of Soil Organic Matter - page 369

J. Scullion and A. Malik OMin Restored Soils as Affected by Earthworms and Land Use

5.4

Organic Matter in Restored
Soils as Affected by
Earthworms and Land Use

J. S CULLION 1

AND A. M ALIK 2

1
Institute of Biological Sciences, University of Wales,Penglais,
Aberystwyth SY23 3DE, UK; and 2 425/8-A Tench Road,
Rawalpindi, Pakistan

Introduction

Early evidence (Hunter and Currie, 1956) has suggested that soil restored
after opencast mining for coal lacks stable aggregation, has low organic
matter levels and altered organic composition. More recently, Malik and
Scullion (1998) showed that restored soils had particularly low carbo-
hydrate contents compared with similarly managed undisturbed soils. This
later study also indicated differences between restored and undisturbed
soils in relationships between microbial C, respiration and total soil carbon
as found in other studies on restored soils (Insam and Domsch, 1988;
Gilsotres et al ., 1992).
Earthworm abundance is drastically reduced by soil handling practices
(Rushton, 1986), and full recovery may take in excess of 20 years (Scullion,
1994). Malik and Scullion (1998) showed that earthworms increased
aggregation and affected the composition of organic matter in restored
soils. The present study reports on the recovery of organic matter levels and
cycling in restored soils, relating this process to aggregation, earthworm
populations and land use.

Methods, Sites and Experimental Details

Data are presented from three studies investigating different aspects of
soil rehabilitation after opencast mining. All sites were sampled during
1993/94. In the first study, changes in organic content and composition in