What occurs when the C:N ratio is higher than the ideal?

When the carbon to nitrogen (C:N) ratio is higher than the ideal level for microbial activity, nitrogen becomes immobilized. This process occurs because microorganisms require both carbon and nitrogen for their growth and metabolism. In scenarios where there is an abundance of carbon relative to nitrogen, these microorganisms consume the available nitrogen from the soil or plant tissue to break down the excess carbon. As a result, nitrogen becomes less available in the soil for plant uptake during this decomposition phase.

A high C:N ratio typically indicates that the organic matter being decomposed is rich in carbon but low in nitrogen, which can lead to a temporary deficiency of nitrogen available for plant growth. This is why maintaining an appropriate C:N ratio is essential for effective nutrient management and ensuring that plants have access to the necessary nitrogen for their development.