ABSTRACT
Microbiology has flourished ever since the discovery and description of microorganisms as agents —invisible to the naked eye —that are ubiquitous and have key capacities of transforming matter and causing disease. A major characteristic of soil as a biological system is the capacity of surface-reactive soil particles to adsorb key biological molecules, such as proteins and nucleic acids. A plethora of nitrogen fixers, ammonia oxidizers, nitrate reducers, sulfate reducers, iron reducers, next to fermenters, and straightforward aerobic organic carbon degraders could be isolated from soil. A large suite of developments with respect to the mechanisms that underlie interactions in soil also aims to unravel the molecular events that trigger particular associative or antagonistic responses. The role of soil organic matter (SOM) as the basis of soil fertility across many soils has been extensively documented. Interactions between SOM and complex human–natural systems require new research into regional and global SOM budgets.
