Add Grain Yield correction

sunflo/src/ElaborationRendement.cpp

@@ -238,10 +238,12 @@ public :
                     // traduit condition TT_A2 < date_TT_F1
                     IRs_tmp = 0.0;
                 } else {
-                    IRs_tmp = 0.416 + (-1.42e-04) * photo_TDM_CROISSANCEACTIVE_A_FLORAISON()
+		// GY converted (no impurity, no humidity,  0.91 * 0.98 = 0.8918)
+                    IRs_tmp = 0.8918*(0.416 + (-1.42e-04) * photo_TDM_CROISSANCEACTIVE_A_FLORAISON()
                                     + (1.19e-03) * NET_EF() + (-8.45e-04) * NET_FM()
                                     + (-2.47e-04) * NET_MH() 
-                                    + (-3.61e-04) * TT_MH() + 7.75e-01 * pv.IRg;
+                                    + (-3.61e-04) * TT_MH() + 7.75e-01 * pv.IRg);
+
                 }
                 IRs = IRs_tmp;
             }