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Calcimator

Soil Biology Assessment Calculator

Interpret PLFA soil biology lab results to assess microbial community composition, food web structure, and biological stress indicators.

Inputs

Results

Biology score (0-100)

58

Fungi:Bacteria ratio0.17
Gram+:Gram- ratio1.25
AMF community share (%)4.4%
Microbial biomass C (μg/g)225
Biomass RatingModerate
Food Web TypeModerately bacterial (typical managed soil)
Stress LevelNormal
How to Use This Calculator
  1. Enter soil respiration rate (CO2 flux) from a Solvita or jar test in ppm per day.
  2. Input your active carbon (POXC) and protein index (ACE protein) values from lab tests.
  3. Set your soil type and tillage history.
  4. Review the Biological Activity Score and the Haney Soil Health Score.
  5. Use the Limiting Factor output to prioritize the input or practice that will yield the largest improvement.

What each input means

Total PLFA (nmol/g)
Total phospholipid fatty acids from lab report (nmol/g dry soil).
Fungal PLFA (nmol/g)
Fungal biomarker PLFA (18:2ω6,9).
Bacterial PLFA (nmol/g)
Total bacterial biomarker PLFAs.
AMF PLFA (nmol/g)
Arbuscular mycorrhizal fungi biomarker (16:1ω5).
Gram+ bacteria (nmol/g)
Gram-positive bacterial biomarkers.
Gram- bacteria (nmol/g)
Gram-negative bacterial biomarkers.

What each result means

Biology score (0-100)
Composite soil biology health score.
Fungi:Bacteria ratio
Higher values indicate more mature, fungal-dominated food webs.
Gram+:Gram- ratio
Values >2.0 suggest environmental stress (drought, compaction).
AMF community share (%)
Mycorrhizal fungi as percent of total community — higher is better for plant nutrition.
Microbial biomass C (μg/g)
Estimated microbial biomass carbon from PLFA total.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Total PLFA (nmol/g) = 45, Fungal PLFA (nmol/g) = 5, Bacterial PLFA (nmol/g) = 30, AMF PLFA (nmol/g) = 2 = 6 input(s) provided
  2. Calculate Biology score
    Biology score = min(100
    58 = 58
  3. Calculate Fungi:Bacteria ratio
    0.167 = 0.167
  4. Calculate Gram+:Gram- ratio
    1.25 = 1.25

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