The conversion of SOM or vice versa C using the factor ranging from 0.58 to 1.724 (called van Bemmelen factor) is often l used and frequently criticized as the amount of carbon in some specific types SOM can be  different from 1.724 so conventionally and frequently used. An App for mobile devices with rough soil data (grids 1km), including soil organic carbon, is available at http://http://soilinfo.isric.org/

A critical review of the conventional SOC to SOM conversion factor (Geoderma,Volume 156, Issues 3–4, 15 May 2010, Pages 75-83 )...PDF enclosed for further reading

Abstract : Use of a single factor for converting soil organic carbon to soil organic matter is challenged. The basis for this challenge arises from four sources: the original papers published in the nineteenth century, empirical studies published throughout the twentieth century, theoretical considerations of organic matter composition, and a consideration of what led to the popularity and general acceptance of the conventional factor. The conventional factor of 1.724, based on the assumption that soil organic matter contains 58% carbon, applies only to some soils or only to particular components of soil organic matter. Studies published since the end of the nineteenth century have consistently shown that the factor of 1.724 is too low for most soils. In a review of previously published data, the median value for the conversion factor was found to be 1.9 from empirical studies and 2 from more theoretical considerations. A factor of 2, based on the assumption that organic matter is 50% carbon, would in almost all cases be more accurate than the conventional factor of 1.724. A consideration of the possible variation in organic matter composition predicts a range of factor values between 1.4 and 2.5, a range that is narrower than empirical results at least in part because of the interaction between the methods used to estimate organic matter and soil composition. Convenience, authority, and tradition rather than strength of evidence are in large part responsible for the widespread acceptance of the conventional factor

The amount of organic carbon to 10cm depth in soil with a carbon value of 1.5% and bulk density of 1.3g/cm3 is:15 (g C/kg soil) x 1 300 000 (kg soil/ha) = 19.5t C/ha or1.5 x 1.3 x 10 = 19.5t C/ha

Adjusting for gravel content

If there is gravel in the soil sample, laboratory results will need to be adjusted as this is taken out before carbon analyses.So if SOC was 1.5% but soil had 25% gravel (by volume) then: 1.5 - (1.5 x 0.25)  = 1.1% SOC

The App SOC plus a tool to estimate and calculate organic carbon in the soil profile by Baustita and his group , Journal of Applied Research and Technology 14 (2016) 135–139 ..PDF enclosed

Is the converting from organic carbon to organic matter depend on the texture co textural class?

Yes, off course, texture will dictate carbon sink capacity of a given soil ...

The organic carbon holding capacity of a soil varies with texture. For instance, clay soils holding more OM holding capacity than sandy soils. But the general factor used to convert OC to OM is regardless of the texture 1.724. That means: %OM = 1.724 * %OC

Birhanu , of late , this factor of1.724 has been debated heavily , and used differently...

Ok Dr. Anoop, if that is the case, what is the clear conversion factor to be used? Factors such as bulk density, soil depth, OC (mg/g or g/kg soil) and percent gravel content are used to estimate soil organic carbon pool (i.e. used to convert OC concentration (g C/kg soil) into (Mg C/ha). So, how could we convert soil OC into SOM? I mean how to convert the laboratory derived OC result into OM?

http://www.soilquality.org.au/factsheets/organic-carbon

Soil organic matter (SOM) includes all the elements (carbon, hydrogen, oxygen, nitrogen, etc) that are components of organic compounds. Organic matter is difficult for laboratories to measure directly, so they usually measure total organic carbon. This is probably why organic matter and organic carbon are often confused and used interchangeably. A conversion factor of 1.72 is commonly used to convert organic carbon to organic matter:

Organic matter (%) = Total organic carbon (%) x 1.72

This conversion factor assumes organic matter contains 58% organic carbon. However this can vary with the type of organic matter, soil type and soil depth. Conversion factors can be as high as 2.50, especially for subsoils.

The conversion of SOM or vice versa C using the factor ranging from 0.58 to 1.724 (called van Bemmelen factor) is often l used and frequently criticized as the amount of carbon in some specific types SOM can be  different from 1.724 so conventionally and frequently used. An App for mobile devices with rough soil data (grids 1km), including soil organic carbon, is available at http://http://soilinfo.isric.org/

A critical review of the conventional SOC to SOM conversion factor (Geoderma,Volume 156, Issues 3–4, 15 May 2010, Pages 75-83 )...PDF enclosed for further reading

Abstract : Use of a single factor for converting soil organic carbon to soil organic matter is challenged. The basis for this challenge arises from four sources: the original papers published in the nineteenth century, empirical studies published throughout the twentieth century, theoretical considerations of organic matter composition, and a consideration of what led to the popularity and general acceptance of the conventional factor. The conventional factor of 1.724, based on the assumption that soil organic matter contains 58% carbon, applies only to some soils or only to particular components of soil organic matter. Studies published since the end of the nineteenth century have consistently shown that the factor of 1.724 is too low for most soils. In a review of previously published data, the median value for the conversion factor was found to be 1.9 from empirical studies and 2 from more theoretical considerations. A factor of 2, based on the assumption that organic matter is 50% carbon, would in almost all cases be more accurate than the conventional factor of 1.724. A consideration of the possible variation in organic matter composition predicts a range of factor values between 1.4 and 2.5, a range that is narrower than empirical results at least in part because of the interaction between the methods used to estimate organic matter and soil composition. Convenience, authority, and tradition rather than strength of evidence are in large part responsible for the widespread acceptance of the conventional factor

Thank you all for the valuable contribution.

Thank you Dr. Anoop. Interesting article and clarification.

I agree with Dr Anoop Kumar for his fantastic discussions. I like to appreciate him.