This test is done to determine the organic content of the soil. Organic content is the ratio, expressed as a percentage, to the mass of dry soil solids in a given mass of soil.

Standard Reference:

ASTM D 2974 Standard test methods for peat and organic soil moisture, ash and organic matter


Organic matter affects many physical, chemical and biological properties of soil. Some of the properties affected by organic matter include soil structure, soil compressibility and shear strength. In addition, it also affects water holding capacity, nutrient contribution, biological activity, and water and air infiltration rates.


  • muffle furnace,
  • balance,
  • porcelain dish,
  • spatula,
  • tongs
Determination of organic matter in soil
Determination of organic matter in soil

Testing Process:

(1) Determine and record the mass of an empty, clean and dry porcelain dish (MP,

(2) Place a portion of the moisture content experiment or the entire oven-dried test sample in the porcelain dish and determine and record the mass of the dish and the soil sample (Mpublic distribution system,

(3) Place the dish in a muffle furnace. Gradually increase the temperature in the furnace to 440 . do0c. Leave the sample in the furnace overnight.

(4) Using tongs, carefully remove the porcelain dish (the dish is very hot), and let it cool to room temperature. Determine and record the mass of the dish containing the ash (burnt soil) (Mthe countryside,

(5) Empty and clean the vessel.

Data Analysis:

(1) Determine the mass of dry soil.

MD= mpublic distribution system-MP

(2) Determine the mass of ash (burnt) soil.

Ma= mthe countryside-MP

(3) Determine the mass of the organic matter

Mhey = mD – Ma

(4) Determine the organic matter (material).

OM = (mhey/MD)*100

article written by

Pro. Krishna Reddy, UIC

Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.