Agrotest Analytical Laboratory · Since 2004
PLFA Soil Analysis
- Agrochemical Soil Analysis
- Precision Farming
- Soil Health
- Water Analysis
- Plant Analysis
- Fertilizer Analysis
- SAP Analysis of Plants
The Agrotest Laboratory measures the living microbial biomass in soil using the phospholipid fatty acid method and issues a report detailing the ratio of fungi to bacteria. Turnaround time: 1–4 days after receipt of the sample.
What does a PLFA soil analysis determine?
A true real-time "living snapshot" of your soil's microbial community
- Total microbial biomass total biomass of living and metabolically active microorganisms
- Microbial community structure gram-positive and gram-negative bacteria, actinobacteria and fungi
- F:B and G+/G− ratios ratio of fungi to bacteria and of the main bacterial groups
- Physiological stress indices microbial stress level based on the composition of membrane (phospholipid) fatty acids
The method determines the membrane phospholipids of living microorganisms. Since they break down within a few hours after cell death, this indicator reflects only the active microbial community at the time of sampling, with no traces of dead cells.
The analysis quantitatively assesses the total microbial biomass (ng/g) and its specific groups: gram-positive and gram-negative bacteria, actinomycetes, saprophytic fungi, and arbuscular mycorrhizae. Each group has its own markers: 16:1ω5c indicates mycorrhizae, while 10-methyl acids point to actinomycetes.
Ratios are calculated separately. The fungi-to-bacteria (F:B) ratio increases under minimum tillage and reflects the type of organic matter decomposition. These indicators do not have universal benchmarks, so their true value comes from comparing the field’s dynamics over time.
Who is this test intended for?
We work with farms of all sizes—from backyard plots to agricultural holdings.
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01
Growers comparing tillage systems
After intensive cultivation
tillage systems -
02
Farmers using cover crops
To assess microbial biomass, the fungi-to-bacteria ratio and changes in the soil microbiome.
cover crops -
03
Agronomists adjusting the fertilization system
To compare microbiome structure and the condition of microorganisms under different fertilization approaches.
fertilization system -
04
Farming businesses monitoring the soil microbiome
To determine living microbial biomass, the main groups of microorganisms and ecological indices.
soil microbiome
PLFA analysis indicators
General Parameters
Total microbial biomass
01The sum of all PLFAs, representing the living and metabolically active microbial biomass of the soil.
Biomarker groups
05Combined indicators for gram-positive and gram-negative bacteria, actinobacteria, saprophytic and arbuscular mycorrhizal fungi.
Ecological ratios
02Ratios of fungi to bacteria and of gram-positive to gram-negative bacteria.
Physiological stress indices
03Ratios of cell membrane fatty acids that characterize the physiological state of the microbial community.
When to Order a Soil Analysis
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01
When changing the tillage system
When you need to compare microbial community structure under different soil tillage approaches.
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02
When using cover crops
When you need to assess changes in microbial biomass and soil microbiome structure.
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03
When changing the fertilization system
When you need to compare the state of the microbial community under different fertilization approaches.
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04
To assess microbial biomass and calculate soil health
When you need to quantify living and metabolically active microorganisms in the soil.
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05
To analyze microbiome structure
When you need to identify the main groups of bacteria and fungi and the F:B and G+/G− ratios.
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06
To assess physiological stress
When you need to determine stress indices and the state of the microbial community.
How to Order a PLFA Soil Analysis
Defining the Research Objective
The process begins with defining the objective: monitoring the transition to no-till farming, evaluating cover crops, testing biological products, or comparing plots. The sampling design and the frequency of repeat measurements depend on the objective.
Sampling
From each plot, 10–15 spot samples are collected at a depth of 0–10 cm and combined into a composite sample. The sampling points are georeferenced using GPS and the samples are collected during the same season as the previous time.
Storage and Transmission
The sample is immediately cooled or frozen; in warm weather, it is transported with ice packs. Failure to maintain the proper conditions distorts the results for Gram-negative bacteria and fungal markers.
Report and Interpretation
The report includes biomass by group, the F:B ratio and the Gram-positive:Gram-negative ratio, as well as the diversity index. The results are compared with previous samples from the same field. The analysis is combined with the Haney test and agrochemistry.
Equipment and Research Methods
State-of-the-art equipment
Tests are performed using certified analytical equipment in accordance with international standards. Most of the instruments are automated, which minimizes the impact of human error. The accuracy of the measurements is verified through regular internal quality control and external audits conducted under the ALP system.
Working Methods
Accredited analytical methods adapted for various types of Ukrainian soils
Examples of Analysis Results
Take a look at the sample lab reports and interpretation tables that you receive after the analysis is completed.
Documents
Certificates Agrotest
Verified quality of laboratory measurements—from state accreditation to international measurement quality control programs.
WARD Laboratories
Regular professional development at the Ward Laboratory.
Agricultural Laboratory Proficiency Program
Recognition of Measurement Capabilities
Mobile app
Agrotest Pro
Test results, field maps, and recommendations—all in one place. Satellite views, NDVI layers, and details about each field—available on iOS and Android.
Frequently Asked Questions About PLFA Soil Analysis
We've compiled answers from Agrotest laboratory experts to our clients' most frequently asked questions. If you can't find the information you're looking for, please submit a request—our specialists will provide you with detailed advice.
An agrochemical analysis measures available nutrients and calculates fertilizer application rates. PLFA reveals the living microbial biomass and its structure—that is, not “how much nutrition” but “who is active in the soil and in what balance.”
Request
Request a test
Give us a call — we’re here to help!
Free consultation with an agronomist
Selection of the optimal analysis package
Completed report within 5–10 business days