Bacteria

 

 

Rhizobia (leguminous plants) - Convert N2 gas into NH4

Rhizobia are soil bacteria that fix nitrogen after becoming established inside the root nodules of legumes. Rhizobia require a plant host; they cannot independently fix nitrogen. These bacteria have an intimate relationship with leguminous roots, turning N2(Nitrogen Gas) into NH4(Ammonium) for improving soil pH.


 

Actinobacteria

Actinobacteria are indeed a very interesting group of microorganisms. At first glance these chains of bacteria look strikingly similar to a fungal strand, but genetic analysis of actinobacteria has revealed that they are indeed prokaryotes containing no bound nucleus versus the eukaryotic fungi!

Actinobacteria are the agents responsible for the rich aroma of healthy soil. While about 90 percent of plants maintain a symbiotic relationship with fungi called Mycorrhizae, about ten percent of plants enter into a different sort of relationship with Actinobacteria. Actinobacteria produce certain compounds that act as soil fumigants on fungi, impeding the development of any mycorrhizal relation or parasitic predation towards the plant. This allows actinobacteria to work with the plant and greatly improve its immunity.


 

Microaggregates and Macroaggregates

Glues for Hyphae structures - The massive diversity of soil biology contains thousands upon thousands of small groups of bacteria, called Microaggregates. These small clusters of bacteria excrete materials that act as glue, sticking to fungal hyphae and building large living structures called Macroaggregates. The grouping of these bacteria and fungi helps to form soil structure, giving it shape and retaining nutrients that can be utilized and extracted by the biology living within it.

 

For more information, please see:

Teaming With Microbes, by Jeff Lowenfels and Wayne Lewis

The Soil Biology Primer, by Elaine Ingham

http://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053862