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[compostteas] Microbial indices of soil fertility -- J. Appl. Microbiology (Feb 2005)

This is a new online journal article (Feb 2005) that
identifies 'keystone' biological parameters for soil fertility.

It is based on soil analysis of 16 agricultural fields managed
in a cropping systems trial in Japan since 1984, using organic
fertilizers, chemical fertilizers, a blend of organic and chemical
fertilizers, and a control as treatments.

The microbial analysis procedures -- Fatty acid methyl ester
(FAME) and terminal-restriction fragment length polymorphism
(T-RFLP) -- were revealing and said to be rapid and inexpensive.

Differences in bacterial and fungal community structure, and
bacteria-to-fungal ratio were apparent based on long-term
soil treatments.


"Keystone species are defined based on the concept that
'a limited number of organisms and groups of organisms
seem to control the critical processes necessary for
ecosystem functioning'."

"Fatty acid methyl ester (FAME) analysis and terminal-restriction
fragment length polymorphism (T-RFLP) analysis have been
used to characterize microbial community structure in soils.
FAME analysis method could extract fatty acids from whole
cells, not only phospholipids but also neutral lipids and
glycolipids. It is known that some unique fatty acids are
contained in neutral lipids and glycolipids (Steiner et al. 1988).
Hence, this method could accumulate more diverse fatty acids,
and enable us to classify more sensitively the microbial groups."

"T-RFLP analysis has been shown to be effective in discriminating
between microbial community structures in a range of environments
(Dunbar et al. 2000; Buchan et al. 2002; Kuske et al. 2002;
Konstantinidis et al. 2003; Nikolcheva et al. 2003). This analysis
is highly reproducible and high-quality fingerprints consisting of
fragments of precise size (Osborn et al. 2000) enable us to analyse
many samples, making the analysis useful in field-scale studies.
Thus, we tried to find 'keystone' biological parameters for soil fertility
using FAME and T-RFLP analyses in agricultural soil that had
been maintained under continuous long-term fertilizer conditions."


Steve Diver


Microbial indices of soil fertility

Journal of Applied Microbiology
OnlineEarly (Online publication date: 18-Feb-2005)



C. Suzuki, T. Kunito, T. Aono, C.-T. Liu and H. Oyaizu


Aims: To find the new microbial parameters explaining the soil
fertility from the microbial community viewpoint.

Methods and Results: Fatty acid methyl ester (FAME) analysis
and terminal-restriction fragment length polymorphism (T-RFLP)
analysis were carried out using 16 differently treated plots
from the same field that had been kept under different fertilizer
management systems since 1984. It was found that organic
fertilizer application had small impact, whereas chemical
fertilizer application, especially ammonium-nitrogen fertilizer,
had strong impact on microbial community structures. Principal
component analysis was conducted based on soil chemical
and physical parameters, crop yields, FAMEs and
terminal-restriction fragments (T-RFs) to provide 10 FAMEs
and 10 T-RFs showing strong relation with soil fertility.

Conclusion: We defined these 10 FAMEs and 10 T-RFs
as 'keystone' biological parameters explaining soil fertility
in the soil.

Significance and Impact of the Study: This is the first report
on the FAMEs and T-RFs related to soil fertility. Both analyses
are rapid, inexpensive and reproducible means. As field
assessment needs precise and rapid analysis, FAME and
T-RFLP analyses and these new parameters are very useful
to analyse soil fertility at biological viewpoint.


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