diff --git a/Soil/CENTURY_OrganicMatter/SOMINIT_c.for b/Soil/CENTURY_OrganicMatter/SOMINIT_c.for
index cac0bb1a2..f3a692bd9 100644
--- a/Soil/CENTURY_OrganicMatter/SOMINIT_c.for
+++ b/Soil/CENTURY_OrganicMatter/SOMINIT_c.for
@@ -951,12 +951,15 @@
 !     ************************************************************
         IF (SOM3FRAC(L) < 0.) THEN
           IF (SOM_TOT(L) > 1.E-6) THEN
-!           Adiku equation
-            StableC = 0.15 * (CLAY(L) + SILT(L)) + 0.69    !g/kg
-            StableC = StableC / 10.                        !g/100g
+!           Adiku equation              
+!            StableC = 0.15 * (CLAY(L) + SILT(L)) + 0.69    !g/kg
+!            StableC = StableC / 10.                        !g/100g
 !           Gargiulo's regression
 !           y = 0.0093x + 0.1829
 !           StableC = 0.0093 * (CLAY(L) + SILT(L)) + 0.1829   !g/100g
+!           Changing to the NAPESHM equation 
+            StableC = 0.0053 * (CLAY(L) + SILT(L)) + 0.41    !g/kg
+            StableC = StableC / 10.                        !g/100g
             SOM3FRAC(L) = StableC / SOM_TOT(L)
             Method(L) = 'Regression eqn'
           ELSE
diff --git a/Soil/SoilUtilities/SOILDYN.for b/Soil/SoilUtilities/SOILDYN.for
index dcbfdca3c..addd8c750 100644
--- a/Soil/SoilUtilities/SOILDYN.for
+++ b/Soil/SoilUtilities/SOILDYN.for
@@ -699,7 +699,9 @@ C     Initialize curve number (according to J.T. Ritchie) 1-JUL-97 BDB
             ENDIF
           ENDIF
 
-          OC(L) = (0.15 * (CLAY(L) + SILT(L)) + 0.69) / 10.    !g/100g
+   !   OC(L) = (0.15 * (CLAY(L) + SILT(L)) + 0.69) / 10.    !g/100g 
+   !   Making change based on NAPESHM equation [CM] 1/6/25
+          OC(L) = (0.0053 * (CLAY(L) + SILT(L)) + 0.41) / 10.    !g/100g
           NMSG = NMSG+1
           WRITE(MSG(NMSG),'(I5,I6,2F6.1,F6.2," (estimated)")') 
      &          L, NINT(DS(L)), CLAY(L), SILT(L), OC(L)