ABSTRACT
The release (natural and anthropogenic) and sequestration of carbon has taken on increased significance in recent years due to its potential impact on global climate. Soil plays a key role in the global carbon balance because it supports all terrestrial ecosystems that cycle much of the atmospheric and terrestrial carbon (Rosenberg et al., 1999). Soil (pedosphere) also provides the biogeochemical linkage between the other major carbon reservoirs: the biosphere, atmosphere and hydrosphere (rivers, lakes and oceans). Most carbon cycles between these large dynamic reservoirs with soil as a mediator. In the broad issues of management of C 02and other greenhouse gases, the role that soil serves in the global carbon cycle and as a long-term reservoir of carbon is not well understood or appreciated. However, that role is changing. The pedosphere is considered to be an active and significant component in global carbon emission and sequestration potential (CAST, 1992; Lai et al., 1998c, 1999; Rosenberg et al., 1999). In fact, soil carbon sequestration is considered to be a bridge to the future in controlling increased levels of atmospheric C 02 until other direct or indirect technologies for its control are developed (Edmonds et al., 1996 a, b; Cole et al., 1996; DOE, 1999). Because soil is an important source and sink for carbon, several workshops and conferences have addressed the issue of soil and its role in global climate change and carbon sequestration (Lai et al., 1995a, b, 1998a, b, c, 1999).
