Soil as a Biological System

Soil is an unique biological system with an abundant microflora and a very high microbial diversity. The space occupied by microorganisms is very low because only few microsites have the right set of conditions suitable for microbial life. Surface-reactive particles can adsorb important biological molecules, such as DNA and enzymes, which become resistant to microbial degradation and thus genes are preserved and extracellular enzymes can be reactive when conditions are not suitable for microbial activity. Most soil functions mainly depend on microbial activity but soil fauna can accelerate microbial processes and complete food webs in soil. Omics techniques, such as metagenomics, metatranscriptomics and proteomics, have several probelms when applied to soil. However, if used in a complementary way these techniques are promising for providing an integrated picture of the relationship between composition and activity of soil microflora.