Metrolab Blog

Carbon and Nitrogen Determination in Soils

A carbon-to-nitrogen ratio (C:N ratio) is a ratio of the mass of carbon to the mass of nitrogen in a substance. For example, if we have a C:N ratio of 24:1, this means we have 24 units of carbon to 1 unit of nitrogen. The C:N ratio is important because it has a direct impact on residue decomposition and also nitrogen cycling in soils.
It can, amongst other things, be used as indicator for nitrogen limitation of plants and other organisms. As a rule of thumb, the higher the ratio, the longer it takes for the material to decompose. Likewise, the smaller the ratio is, the more rapidly the plant material will decompose. This also has a direct relationship with the amount of nitrogen that is tied up in the soil that will be available to the next growing plant.
The performance of the VELP CN 802 was evaluated by participating in the Proficiency Testing program organized by WEPAL (Wageningen Evaluating Programs for Analytical Laboratories).
Samples of soil were analyzed using the CN 802 and the results obtained (as C % and N %) were compared with the statistical range accepted by WEPAL.

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