private static double critNFactor(Leaf1 Leaf, Stem1 Stem, double multiplier)
//=======================================================================================
// Calculate Nitrogen stress factor from a bunch of parts
/* Purpose
* The concentration of Nitrogen in plant parts is used to derive a Nitrogen stress index
* for many processes. This stress index is calculated from today's relative nutitional
* status between a critical and minimum Nitrogen concentration.
*/
{
double dm = Leaf.Live.Wt;
double N = Leaf.Live.N;
if (Stem != null)
{
dm += Stem.Live.Wt;
N += Stem.Live.N;
}
if (dm > 0.0)
{
double N_conc = N / dm;
// calculate critical and minimum N concentrations
double N_crit = Leaf.NCrit;
double N_min = Leaf.NMin;
if (Stem != null)
{
N_crit += Stem.NCrit;
N_min += Stem.NMin;
}
double N_conc_crit = N_crit / dm;
double N_conc_min = N_min / dm;
//calculate shortfall in N concentrations
double dividend = N_conc - N_conc_min;
double divisor = N_conc_crit - N_conc_min;
if (divisor != 0)
{
double result = multiplier * dividend / divisor;
return(MathUtility.Bound(result, 0.0, 1.0));
}
}
return(1.0);
}
