WaterSoil: add a threshold parameter

Add a maximal water stress stressH_seuil
Integration of work of M. Chanis on Pea.

AZODYN/exp/AzodynBarley.vpz

@@ -1126,7 +1126,10 @@
  <port name="tNorg">
 <double>0.160000000000000</double>
 </port>
-</condition>
+<port name="stressH_seuil">
+<double>0.4</double>
+</port>
+   </condition>
 <condition name="condClimate">
  <port name="PkgName">
 <string>AZODYN</string>

AZODYN/exp/AzodynPea.vpz

@@ -1120,7 +1120,10 @@
  <port name="tNorg">
 <double>1.500000000000000</double>
 </port>
-</condition>
+<port name="stressH_seuil">
+<double>0.4</double>
+</port>
+   </condition>
 <condition name="condClimate">
  <port name="PkgName">
 <string>AZODYN</string>

AZODYN/exp/AzodynWheat.vpz

@@ -1100,7 +1100,10 @@
  <port name="tNorg">
 <double>0.160000000000000</double>
 </port>
-</condition>
+<port name="stressH_seuil">
+<double>0.4</double>
+</port>
+   </condition>
 <condition name="condClimate">
  <port name="PkgName">
 <string>AZODYN</string>

AZODYN/src/ParametersSoil.hpp

@@ -169,6 +169,9 @@ struct ParametersSoil
     //parametre pour calcul de la transpiration et stress hydrique
     double stressH4;
 
+    //parametre seuil pour le stress hydrique
+    double stressH_seuil;
+
     //Seuil de mottes delta au dessus duquel la FTSW est affectee  (%)
     double Mottes_seuil;
 
@@ -269,6 +272,7 @@ struct ParametersSoil
         stressH2 = Utils::extractDouble(events, "stressH2");
         stressH3 = Utils::extractDouble(events, "stressH3");
         stressH4 = Utils::extractDouble(events, "stressH4");
+        stressH_seuil = Utils::extractDouble(events, "stressH_seuil");
         Mottes_seuil = Utils::extractDouble(events, "Mottes_seuil");
         coef_Mottes = Utils::extractDouble(events, "coef_Mottes");
         JSA_seuil = Utils::extractDouble(events, "JSA_seuil");

AZODYN/src/WaterSoil.cpp

@@ -309,7 +309,9 @@ public:
          if(pp.begin_date + j<pp.date_init_H){
              stressH=1.0;
          } else {
-             stressH =std::max(0.4,ps.stressH1/(1+ps.stressH2*std::exp(-ps.stressH3*(FTSW()-ps.stressH4)))) ;
+             stressH =std::max(ps.stressH_seuil,ps.stressH1/
+                               (1+ps.stressH2*std::exp(
+                                   -ps.stressH3*(FTSW()-ps.stressH4))));
          }
     }