Phospholipid Fatty Acid Analysis
• Phospholipids are essential membrane components of all living
cells
• Viable microbes have an intact membrane which contains fatty
acids as components of its phospholipids
• PLFA analysis is done through a chemical extraction process and
analyzed on a gas chromatograph
• Phospholipids make up a relatively constant proportion of the
biomass of organisms
• Rapid changes in microbial community structure can be detected
by changes in PLFA patterns
PLFA data from Bradford Research
Center
Soil is from 5 soil pits all within a stone’s throw of
each other, top 2 inches of soil, taken from the crop
row or next to plants
1- Soybeans- field has been in continuous tillage for over 50 years
2- Switchgrass- field was in fescue for many years then tilled for a few
years and is now planted with prairie plants
3- No-till corn- field was tilled for a few years but has been no-till the
past few years
4- Hedgerow- woody plants such as sumac have grown up in an old
fencerow
5- Fescue field- long-term fescue with sporadic mowing
PLFA Analysis at Bradford Research Center
3000
Bacteria
Actinomycetes
2500
Biomass (mg/g)
Fungi
Protozoa
2000
1500
1000
500
0
Soybean
Switchgrass
NT Corn
Hedgerow/fescue
Cropping Type
Fescue field
PLFA Sub-categories
500
450
Rhizobia
Arbuscular Mycorrhizal
Saprophytes
400
Biomass (mg/g)
350
300
250
200
150
100
50
0
Cropping System