Carbon - Nitrogen Ratio

Both carbon and nitrogen are very important elements in the life cycle of living organisms. So much so that even the ratio of one to the other is an important parameter that measures the microbial activity of soils or compost.

Before proceeding further, it is important to define the calculation of the carbon ratio. nitrogen. The number indicates how many carbon atoms there are for each nitrogen atom. For example, in a block of matter with 100 carbon atoms and 5 nitrogen atoms, we would say that its carbon to nitrogen ratio (C/N) is 20.

Knowing the carbon - nitrogen concept is essential to correctly manage the organic matter content of a soil or compost.

The micro-organisms are responsible for breaking down the organic matter for their own growth. Their aim is to create new compounds from by-products such as mowing residues, animal droppings or organic matter accumulated in the soil by the growth of plant cover.

This process is called mineralisation.

For micro-organisms, carbon represents the energy needed to carry out their cellular processes. Nitrogen, on the other hand, is the building blocks with which they construct their cellular structures.

The life of these micro-organisms is short. When they die, they leave complex matter transformed into simpler matter. These simple molecules can be easily absorbed by plants.

Sample drawer with 18 cm deep handle

The carbon-nitrogen ratio that must be present in a soil in order for the mineralisation If it is above 10, the micro-organisms would be able to sequester the nitrogen because they have too much carbon available. The nitrogen would not be free because there would be too much carbon and when one bacterium dies, another would immediately take its place. The plant would not be able to absorb nitrogen and there would be a deficit. And if the C/N ratio is less than 8, the rate of mineralisation could be too slow.

When the carbon - nitrogen relationship is focused on the composting the ratio increases. The teacher Peter Landschoot of the Pennsylvania State University explains that the ratio should be close to 25 and never exceed 30.

The composting and mineralisation process is essential for crop development. When working with these materials, it is very important to know the processes and variables that affect their maturation. Therefore, laboratories can help you to know the carbon - nitrogen ratio of your soil or raw material and correct it if necessary.