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Calcimator

Soil Respiration Calculator

Analyze soil CO2 flux measurements with temperature and moisture corrections to assess microbial activity and nutrient cycling.

Inputs

%
%

Results

Standardized respiration (mg CO2-C/g/day)

0.85

Activity score (0-100)57
Temperature factor0.71
Moisture factor1
Annual C mineralized (tons/ac)1,030.16
Est. N mineralized (lb N/ac/yr)171,694
Q CO21.41
RatingModerate
How to Use This Calculator
  1. Enter the CO2 evolved in ppm over the measurement period from a Solvita jar test or field sensor.
  2. Input the measurement duration in hours and the sample mass in grams.
  3. Set the soil temperature at sampling to apply a temperature correction.
  4. Review the Respiration Rate in mg CO2-C per kg per day and the Microbial Activity Rating.
  5. Compare against the baseline for your region to evaluate whether microbial diversity is adequate.

How the result changes with Soil temperature at sampling (°C)

Soil temperature at sampling (°C)Standardized respiration (mg CO2-C/g/day)
03.39
131.38
280.49
400.21

What each input means

CO2 respiration (mg CO2-C/g/day)
Measured CO2 evolution from lab incubation or Solvita test (mg CO2-C per g dry soil per day).
Soil temperature at sampling (°C)
Temperature when sample was collected or incubated. Used for Q10 correction.
Water-filled pore space (%)
Percent water-filled pore space. Optimum: 50-60%. Too wet or dry reduces activity.
Soil organic matter (%)
SOM from soil test — used to estimate metabolic quotient.

What each result means

Standardized respiration (mg CO2-C/g/day)
Respiration corrected to 25°C and optimal moisture for cross-sample comparison.
Activity score (0-100)
Normalized biological activity score.
Temperature factor
Q10 correction factor applied (Q10=2.0).
Moisture factor
Moisture correction applied (1.0 = optimal).
Annual C mineralized (tons/ac)
Estimated total carbon mineralized over 200 active days.
Est. N mineralized (lb N/ac/yr)
Approximate nitrogen released from organic matter decomposition.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    CO2 respiration (mg CO2-C/g/day) = 0.6, Soil temperature at sampling (°C) = 20, Water-filled pore space (%) = 55, Soil organic matter (%) = 3 = 4 input(s) provided
  2. Calculate Standardized respiration
    Standardized respiration = correctedResp / moistureFactor
    0.849 = 0.849
  3. Calculate Activity score
    Activity score = min(100, round((standardizedResp / 1.5) * 100))
    57 = 57
  4. Calculate Temperature factor
    Temperature factor = pow(q10, (soilTemp - 25) / 10)
    0.71 = 0.71

Engine last updated .

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