Carbon Credits (Carbon Farming Initiative—Measurement of Soil Carbon Sequestration in Agricultural Systems) Methodology Determination 2018
Sch 1Calculation of Soil Organic Carbon
Start here
Get a plain-English read of Sch 1
Turn the raw legal text into a practical explanation grounded in Carbon Credits (Carbon Farming Initiative—Measurement of Soil Carbon Sequestration in Agricultural Systems) Methodology Determination 2018.
This Schedule provides for the calculation of the change in soil organic carbon between reporting periods.
To determine this amount, in tonnes of CO2-e:
samples of soil need to be collected and analysed consistent with the requirements of this determination and the Supplement;
the soil organic carbon stock in a sample needs to be calculated in accordance with Division 2;
the soil organic carbon stock and variance in a CEA needs to be calculated in accordance with Division 3;
the change in soil organic carbon stock between the baseline and first sampling round needs to be calculated in accordance with Subdivision 2 of Division 4;
the change in soil organic carbon stock once three rounds of sampling have been completed needs to be calculated in accordance with Subdivision 3 of Division 4.
The sampling, analysis and calculations in this Schedule need to be done separately for the upper soil layer (first 30 centimetres) and the deeper layer of soil. The net abatement amount will be calculated based on the full sampling depth, but data on the upper soil layer will be included in offsets reporting to help Australia report its removals of greenhouse gases in its National Inventory Report.
(a) an individual sample taken from a particular location; or
(b) a composite sample which combines samples taken from a number of locations consistent with any requirements in the Supplement into a single sample under this Schedule.
(2) All samples must be obtained and analysed consistent with the requirements in Division 2 of Part 3 of this determination.
Division 2—Calculating the soil organic carbon stock in a sample
4 Steps for calculating the soil organic carbon stock in a sample
(1) The soil organic carbon stock of sample i (SOCi), in tonnes of soil organic carbon per hectare, must be calculated for each sample taken in a sampling round in accordance with this Division.
(2) The Division must first be applied to the upper layer of soil in each sample, which extends from the surface soil to a depth of 30 centimetres (the 0–30 cm layer).
(a) the deeper layer of soil in each sample (from a depth of 30 centimetres to the nominated sampling depth) (the 30–x cm layer) must be analysed separately: and
(b) the results of the analysis of the 0–30 cm layer and the 30–x cm layer must be added together or combined to apply this Division to the whole sample (0–x cm layer) in accordance with any requirements in the Supplement.
Note: The addition or combining of the results in accordance with the Supplement may include requirements for weighting or adjustments to ensure that they are applicable to the equations and overall carbon stock of the sample.
5 Soil mass of each sample
(1) Calculate the mass of the soil, Mi, in each sample i for the 0-30 cm layer or 0-x cm layer (in tonnes of soil per hectare) using the following equation:
View image in the official sourceis the mass of the soil in the sample layer for sample i, in tonnes of soil per hectare, calculated in accordance with any requirements in the Supplement.
Note: This is based on the actual sample thickness.
(2) The actual thickness View image in the official sourceof a composite sample is the average thickness of the layer across all samples that make up the composite sample.
6 Determining Equivalent Soil Mass (ESM) from sampling round masses
(1) The equivalent soil mass (the ESM), in tonnes per hectare, for each CEA must be calculated in accordance with this section.
(2) The corrected soil masses Mi from equation 6 must be:
(a) ranked from lowest to highest for each CEA; and
(b) assigned a sequential rank k from 1 to the number of samples in the CEA N.
(3) A percentile P must be calculated for each value of k using the following equation:
(4) If one of the percentiles given by equation 7 is 10—the ESM for the CEA is the mass of the soil layer given by equation 6 for the relevant rank of k.
(5) If subsection (4) does not apply—the ESM for each CEA is given by the following equation:
MLB is the corrected soil mass View image in the official sourceof the sample i, which has been assigned the lower bound rank LB as having the value of P from equation 7 closest to and lower than 10, in tonnes of soil per hectare, as given by equation 6.
MUB is the corrected soil mass View image in the official source of the sample i, which has been assigned the upper bound rank UB as having the value of P from equation 7 closest to and higher than 10, in tonnes of soil per hectare, as given by equation 6.
PLB is the percentile P associated with the lower bound rank LB given by equation 7.
PUB is the percentile P associated with the upper bound rank UB given by equation 7.
7 Calculation of SOC stock in each sample
(1) If carbon analysis is undertaken on a homogenised sample as outlined in the Supplement—the View image in the official source for each sample i, in tonnes of carbon per hectare, is given by the following equation:
ESM is determined in accordance with section 6 of this Schedule for the CEA to which the sample belongs, in tonnes per hectare.
OCi is the total mass of organic carbon in the sample layer of sample i, in grams, determined in accordance with any requirements in Supplement.
gGi is the total mass of gravel content of the sample layer of the sample i, in grams, determined in accordance with any requirements in Supplement.
(2) If carbon analysis is undertaken on an intact core as outlined in the Supplement—the View image in the official source for each sample i, in tonnes of carbon per hectare, is given by the following equation:
ESM is determined in accordance with section 6 of this Schedule for the CEA to which the sample belongs, in tonnes per hectare.
OCi is the total mass of organic carbon in the sample layer of sample i, in grams, determined in accordance with any requirements in Supplement.
(3) The actual thickness View image in the official sourcefor a composite sample is the average thickness of the layer across all samples that make up the composite sample.
Division 3—Calculating the soil organic carbon stock and variance for a CEA
Schedule Sch 1 - Carbon Credits (Carbon Farming Initiative—Measurement of Soil Carbon Sequestration in Agricultural Systems) Methodology Determination 2018 - Calculation of Soil Organic Carbon | Zoe