Carbon Nitrogen Ratio,Immobilisation Process,Bound Nitrogen,Accumulation of Nitrogen,Mineralisation,Immobilisation

Carbon Nitrogen Ratio

Carbon Nitrogen Ratio
The amount of carbon and nitrogen present in the soil depicts the C : N ratio (C: N ratio of humus is 10: 1) and this is very critical for the decomposition process. Optimum levels of C: N ratio (80: 1-12 :1) is ideal for maximum decomposition since a favourable soil environment is created to bring about an equilibrium between mineralisation and immobilisation process which will be upset if C: N ratio is less than the optimum.

For example, if the carbon content in the fresh organic matter is higher when compared to the nitrogen content (i.e. if the C: N ratio is high), then there will be more multiplication of microbes and immobilisation of the available nitrogen thus making it unavailable to the plants.

On the other hand, if the fresh organic matter contains more of nitrogen than the optimum, then it will result in accumulation of the mineralised nitrogen in the form of ammonium and nitrates thus increasing toxicity of the environment (since carbon is relatively less, the multiplication of the microbial cells is hindered due to lack of energy).

Towards the end of the decomposition process, C: N ratio becomes small (due to the cessation of microbial multiplication leading to no intake of carbon for energy and lysis of the microbial cells thus resulting in release of bound nitrogen). Due to accumulation of nitrogen, the ratio may reach 10 : 1. Hence whatever be the initial C : N ratio during the early stages of decomposition, it always comes to lie at 10 : 1 towards the end thus stabilising the decomposition process.

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Carbon Nitrogen Ratio