Reconcile tared-container oven-dry and ignited-residue masses with a laboratory-reported loss-on-ignition percentage.
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Reconcile a tared-container loss-on-ignition mass record with laboratory-reported LOI without universally labeling the mass loss soil organic matter.
Recover net dry mass, residue and ignition loss from combined container measurements.
Enter tare, constant dry, ignited-residue and reported LOI records from one method/batch.
Sees the calculated LOI and signed laboratory difference.
Keep furnace, cooling, balance, blanks and standards visible.
Review the exact method and batch controls when the arithmetic differs from the report.
Does not hide a tare, transcription or method-basis problem.
Avoid treating raw ignition loss as a universal OM or carbon value.
Use the accredited laboratory result and its validated local conversion/regression.
Does not make fertility or carbon decisions from raw mass loss alone.
Outputs and checklists are planning aids. Review the linked current authorities and the records, terms, instructions, and requirements that apply to your exact situation before a consequential decision.
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Net oven-dry sample mass equals container-plus-dry mass minus the tared container. Net ignited residue uses the same tare, preventing the container from being counted as sample.
Ignition mass loss equals net dry mass minus net residue, and raw LOI percent equals that loss divided by net dry mass times 100. The residue cannot exceed the dry combined mass or fall below the tare.
Calculated raw LOI minus the laboratory-reported LOI gives a signed arithmetic difference. Preserve the exact drying, ignition, cooling, balance, sample-basis, and quality-control method when interpreting it.
Updated: August 2026
Recompute LOI from the tared container, constant dry mass, and cooled ignited-residue records before final reporting.
Investigate a difference beside blanks, standards, duplicates, balance records, furnace program, cooling, and sample preparation.
Share the raw mass-loss record without relabeling it organic matter or carbon unless the laboratory method supplies a validated conversion.
Calculate both net dry sample and net ignited residue from the same tared container before computing the percentage.
Hydrated water, clay and other minerals, carbonates, temperature, time, and sample matrix can affect loss. Use the exact method and locally validated conversion or regression.
This laboratory worksheet checks raw loss-on-ignition arithmetic from a tared container and compares it with the entered report. It deliberately avoids a universal conversion from ignition mass loss to soil organic matter or organic carbon.