04-02-08  New Version 2.31.

 Introduced preliminary N-fixation to plants. The switch N Fixation that also previously is part of Plant Growth. New output variables are “N FixationPlant”  (Transfer). The demand for N fixation is controlled by the carbon assimilation by photosynthesis. After mineral N uptake of N all remaining demand may be simulated as N fixation. The degree of uptake in relation to the total demand is controlled by the parameter NFixCoef (0-1) that may be specified for each plant in the parameter table: “Nitrogen Fixation”. An additional state variable “AccNFixation” is defined in the group “Additional Biotic Variables”.

Introduced N uptake from deposition to Leaf in the module “external inputs”. The previous parameter was not used to calculate any actual uptake. The specific plants uptake is related to an uptake rate that is related to the specific LAI of each plant. The parameters “Dep N to Leaf” is in the parameter table “Specific N Deposition uptake leaf”. Note that the rate is made proportional to the LAI of each plant. The uptake to each plant is defined by the transfer variable “Deposition N Leaf” and the total uptake of all plants are defined in the auxiliary variable  “Total Deposition N Leaf”.

A bug was deleted that caused erroneous N-uptake if more than one plant was defined.        PEJ