Question

If depolymerization were inhibited, why might nitrogen mineralization rates also decline?

Answer 1

This is because of the deceleration of the entire N cycle in cryoturbated soil horizons, especially strongly reduced rates of protein depolymerization (16% of organic horizons) which is considered the rate-limiting step in soil N cycling.

Nitrogen mineralization is the process by which organic N is converted to plant-available inorganic forms.

Immobilization of nitrogen depends on the C/N ratio (30:1) of the plant residues. As carbon dioxide is released via depolymerization the C:N ratio of the organic matter decreases, and the microbial demand for mineral nitrogen is decreased. The nutrient depolymerization declined with increasing diversity due to a negative competitive effect of coalitions on generalist producers, leading to less overall enzyme production. Depolymerization regulates overall nitrogen cycling.