Evaluation of Two Field Methods to Estimate Soil Organic Matter In Alberta Soils: Appendix 2 - Lab Procedures for LFC and OM (%)

The Norwest lab values for the percent organic matter were obtained using a loss on ignition method (McKeague 1978).

The University of Alberta lab values for the light fraction carbon (LFC) were obtained using a loss on ignition method (University of Alberta 2002). The carbon and nitrogen content of the light fraction material was obtained through a dry combustion process using Carlo Erba instrumentation.

Calculation of the LFC (mg/kg) was then completed as outlined below (Figure 10).

Example of Calculation of Light Fraction Carbon
Used data from B.H. Prairie, Site #586
.
From Lab:
LF (Wt) g = 0.1776 per 20 grams soil
% Carbon as LF material = 28.918
Therefore:
0.1776 g LF	x	28.918% Carbon as LF			equals	0.00256792 g LFC
20 grams soil	x		100			1 g soil

To convert to mg/kg:

0.00256792 g LFC	x	1000 mg	x	1000 g	equals	2567.92 mg LFC
1 g soil	x	1 g	x	1 kg		kg soil

Figure 10. Calculation of light fraction carbon (LFC).

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This information published to the web on May 4, 2004.
Last Reviewed/Revised on November 6, 2018.