Science Forums 2

[Michaelangelica]

Rhizosphere = round Rhizos?

Eric's "wee beastie" Condos with in built security systems against 'bad guys'

Mechanism 2: Biochar alters the activity of other
micro-organisms that have effects on mycorrhizae
. . .
Hyphae and bacteria that colonize biochar particles (or other porous materials) may be protected from soil predators (Saito 1990; Pietikäinen et al. 2000; Ezawa et al. 2002), which includes mites, collembola and larger (>16 μm in diameter) protozoans and nematodes.
The documented physical parameters of the biochar particles themselves make this mechanism plausible.
The average sizes of soil bacteria and fungal hyphae range from 1 to 4 μm and 2 to 64 μm, respectively, with many fungal hypha being smaller than 16 μm in diameter (Swift et al. 1979).
Additionally, the average body-size of a soil protist is between 8 to 100 μm, while the average body size of soil micro-arthropods ranges from 100 μm to 2 mm (Swift et al. 1979).
In contrast, the pore diameters in a biochar particle can often be smaller than 16 μm in diameter (Kawamotoet al. 2005; Glaser 2007; Hockaday et al. 2007).
Based on the differences in the body sizes across these different organisms, it is clearly possible that many of the pores within a biochar particle are large enough to accommodate soil microorganisms, including most bacteria and many fungi, to the exclusion of their larger predators.
Thus, the biochar would be acting as a refuge for MHB, PSB and mycorrhizal fungi.

Supporting evidence for this hypothesis comes from Saito (1990), Gaur and Adholeya (2000) andEzawa et al. (2002) who all showed that AMF readily colonize porous materials and were capable of heavily colonizing biochar particles in the soil.

Lastly, Pietikäinen et al. (2000) and Samonin and Elikova (2004) showed that bacteria readily colonized biochar particles; these may include MHB and/or PSB.

http://www.css.cornell.edu/faculty/l...%20Warnock.pdf