Activity of soil micro-organisms.

[EWEN]

Following Dorothea Smith's recent post on monitoring activity of the 
Soil Microbial Biomass (Hereafter and forever referred to as the SMB).

Hello Dorothea,

Yup, tricky one. I would normally use the TTC method myself, but when 
you mentioned phenols and nitrates....

I've been looking at the various forms and techniques for the 
estimation of the SMB for a while now, and whilst I don't want to be 
seen to blow my own trumpet, have you considered rather than a 
measure of the activity trying to extrapolate from other measures ?

See Hill, McPherson et al, Soil Biology and Biochemistry Vol 25(12) 
pp 1779-1786, 1993. Title;-Microbial biomass estimated by 
phospholipid phosphate in soils with diverse microbial communities.

We started looking at phospholipid phosphate (PL-P) as an alternative 
measure of the SMB, and came up with the following corellations from 
a very diverse range of soils from our previous research work;-

ATP;- r^2= 0.80, p<0.001
Total N;- r^2 = 0.84, p<0.001
DHA;- r^2 = 0.53, p<0.005
and from Zelles et al (1991)
they showed r^2 of 0.94-0.96 for "a range of enzymatic measures"
in agricultural soils.

I'm not personally a great fan of ATP as a method for the estimation 
of activity, but it seems like this might be your best bet given the 
circumstances you're looking at. I'll be happy to point you to some 
references if you're not already aware of the technique.

Hope this is of some use to you,

Regards,

Ewen


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