ABSTRACT
This chapter focuses on the interaction of particulate organic matter (POM) with mineral particles and considers the role of POM in the formation of aggregates of different sizes. It presents a conceptual model describing the involvement of POM and microbial metabolites derived from its decomposition in soil aggregation. The chapter identifies the importance of biological processes associated with the decomposition of POM and the associated chemical changes with respect to their involvement in the proposed model of aggregation. The conceptual model may be applied generally to soils where organic matter is an important agent responsible for binding soil mineral particles together creating an aggregate hierarchy. Studies related to the decomposition of plant residues indicate that free POM is readily decomposed in soils. The ability of microaggregate-POM to form stable associations with soil mineral particles is related to the extent of POM decomposition.
