Soil organic carbon data model

[ktoddbrown]

Soil organic carbon stock either reports mass-per-volume and is calculated from bulk density, organic carbon fraction, and coarse fraction with specified units. Note that we are focusing this to be a volume calculation for this project.

A data model might look something like this:

---
soil_organic_carbon:
  definition: text or url
  value: numeric
  unit:
    - one_of:
        - g cm-3
        - kg m-3
  function:
    - one_of:
        - coarse_fraction_uncorrect: bulk_density * organic_carbon_fraction
        - coarse_fraction_correct: bulk_density * organic_carbon_fraction * (1 - coarse_fraction)

Since bulk density, organic carbon fraction, and coarse fraction are all associated observations let's put them all together in this discussion.

bulk_density:
  definition: text or url
  value: numeric
  unit:
    - one_of:
        - g cm-3
        - kg m-3
  method:
    - moisture_status:
        - one_of:
            - oven dry
            - air dry
            - field moist
    - coarse_fraction:
        - one_of:
            - included:
                - definition: coarse fraction was not removed
            - excluded:
                - definition: soil fragments above sieve_size were removed
                - sieve_size:
                    - value: numeric
                    - unit:
                        - mm
    - pedotransfer_function:
        - description: text

---
coarse_fraction:
  definition: text or url
  value: numeric
  unit:
    - g g-1
  method:
    - one_of:
        - included:
            - definition: course fraction was not removed
        - excluded:
            - definition: soil fragments above sieve_size were removed
            - sieve_size:
                - value: numeric
                - unit:
                    - mm

---
organic_carbon_fraction:
  definition: text or url
  value: numeric
  unit:
    - g g-1
  method:
    - one_of:
        - loss_on_ignition:
            - oven_temperature:
                - value: numeric
                - unit: degree C
            - duration:
                - value: https://en.wikipedia.org/wiki/ISO_8601#Durations
        - Walkley_Black
        - MIR:
            - library: text
            - data_algorithm: text
        - NVIR:
            - library: text
            - data_algorithm: text
        - pedotransfer_function:
            - description: text