ABSTRACT
References.................................................................................................... 405
Further Reading ........................................................................................... 407
The biotic functions of soils are mediated by a diverse range of organisms
spanning multiple trophic levels whose interactions serve to regulate key
activities such as nutrient cycling. The primary nutrients in soils arise from
organic material deposited by animals and plants which is cycled by the
decomposer community. In this way, nutrients are made available to plants
and species of higher trophic levels. Although the biological and physical
heterogeneity of soil makes it a particularly difficult environment to study, it is
widely understood that microbes are responsible for much of the decomposing
and nutrient recycling activity. On a cellular level, the most abundant and
taxonomically diverse groups of microbes occurring in soil are the bacteria.
As outlined in Chapter 2, there is an extremely high diversity of bacteria in soil
[1,2], with many different groups and species undertaking active roles in the
functionality of the soil at a given time. Given this recognized high diversity, it
is now important to further our understanding of what these taxa are actually
doing, as well as to improve our knowledge of how changes in agricultural or
environmental factors affect microbial communities and their functions [3].
