Do composts affect the soil microbial community?

Abstract

Compost amendments have been shown to provide manifold benefits, as long as compost of good quality is used and care is taken not to accumulate heavy metals or organic pollutants as a consequence of repeated applications. Among the advantages of compost as soil amendment is its potential to maintain soil organic matter, foster nutrient availability, suppress plant diseases and increase soil microbial abundance and activity, thus enhancing soil quality and fertility. However, only little is known about how compost amendments act as microbial inoculum to the soil and if the compost-borne microflora leaves a long-term imprint on soil microbial communities. In this chapter, it will be analysed if and to what extent soil microbial biomass, activity and community structure are affected by compost amendments. A long-term field study, in which four different composts have been applied annually since 1991, will be presented in detail.