Ecosystem productivity is independent of some soil properties at equilibrium

Long runs of a mechanistic model of forest carbon (C) and nitrogen (N) dynamics (Edinburgh Forest Model) suggest that, when in a steady state, ecosystem productivity may be insensitive to the specific rate of N mineralization of soil organic matter (SOM). At equilibrium, productivity and other vegetation properties are determined primarily by climate. This is so because, given time, modelled ecosystems tend to generate amounts of SOM that are able to supply N at rates which do not greatly limit plant growth. When specific N mineralization rates are low, large amounts of SOM accumulate, whereas when specific N mineralization rates are high, small amounts of SOM accumulate. However, it may take several millenia for equilibrium conditions to be reached following disturbance (particularly following degrading disturbance) and during that time N mineralization rates determine the speed of progress toward equilibrium.