Which process can be negatively affected by high carbon to nitrogen ratios?

A high carbon to nitrogen (C:N) ratio can significantly impact various soil processes, but it primarily affects mineralization. Mineralization is the process where organic matter is broken down by microorganisms into inorganic forms, making nutrients available for plant uptake. In instances where the C:N ratio is high, there is an abundance of carbon relative to nitrogen. Microorganisms require both carbon and nitrogen for their growth and metabolism, but they prefer nitrogen.

When there is insufficient nitrogen available due to a high C:N ratio in the organic material, microbial activity slows down because the microbes cannot complete the decomposition process efficiently. This results in reduced mineralization rates, leading to a decrease in the conversion of organic nutrients into forms that plants can absorb, eventually affecting plant growth and soil fertility.

Conversely, scenarios like immobilization, where nutrients are temporarily taken up by microbes, can indicate a different dynamic that does not directly illustrate the primary effects of a high C:N ratio. Volatilization and leaching pertain more to losses of nutrients rather than the transformation processes dictated by C:N ratios. Therefore, mineralization is the most directly impacted process under these circumstances.