diff --git a/CarbonCalculation.cs b/CarbonCalculation.cs
index 348ca48..ae32069 100644
--- a/CarbonCalculation.cs
+++ b/CarbonCalculation.cs
@@ -225,6 +225,18 @@ namespace FarmMapsAPI.Carbon
         {
             var knmiFile = Helper.GetPlatformIndependentDirectoryPath(Path.Combine(configPath, "KNMI_data.csv"));
 
+            if (farmInput.CropFields[0].SoilProperty.OM_Choice == "c")
+            {
+                //carbon_organicmatter_factor = 1;
+                farmInput.CropFields[0].SoilProperty.C_Const = farmInput.CropFields[0].SoilProperty.OM_Const;
+                farmInput.CropFields[0].SoilProperty.OM_Const = 0;
+            }
+            else
+            {
+                farmInput.CropFields[0].SoilProperty.C_Const = farmInput.CropFields[0].SoilProperty.OM_Const * 0.54;
+            }
+
+
             // soilTypeData (external input)
             var soilTypeData = GetSoilTypeData(farmInput);
 
@@ -239,7 +251,8 @@ namespace FarmMapsAPI.Carbon
 
             var year = GetYears(farmInputSet, farmInput);
 
-            
+            //var carbon_organicmatter_factor = 0.54;
+
             //////////////////////////////////////////////
             // precalculations
             //////////////////////////////////////////////
@@ -253,14 +266,18 @@ namespace FarmMapsAPI.Carbon
             {
                 var soilProps = soilPropSoilType.Keys.Where(x => x.Item1 == item.Key).ToList();
                 var sumCorr = 0.0;
+                var sumC_Corr = 0.0;
                 foreach (var soilProp in soilProps)
                 {
                     sumCorr += soilPropSoilType[soilProp].OM_Corr;
+                    sumC_Corr += soilPropSoilType[soilProp].C_Corr;
                 }
                 item.Value.OM_Corr = sumCorr;
+                item.Value.C_Corr = sumC_Corr;
             }
 
             var oM_corr_SoilType = new Dictionary<(string,string), double>();
+            var C_corr_SoilType = new Dictionary<(string, string), double>();
             foreach (var item in soilPropertiesField)
             {
                 var soilOfItem = soilTypeData[item.Key].FirstOrDefault();
@@ -276,25 +293,35 @@ namespace FarmMapsAPI.Carbon
                 parameterSet.LayerDepth = item.Value.Depth.HasValue? item.Value.Depth.Value : parameterSet.LayerDepth;
                 if (initialSoil == "Temp_gras" && soilPropertyDepth10)
                 {
-                    oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.97);
+                    oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.97 * (1 / 0.54));
+                    C_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.97);
                 }                
                 else if (cropSet.Grass_nat.Contains(initialSoil) && soilPropertyDepth10 && (soilOfItem == "Klei" || soilOfItem == "Zand"))
                 {
                     if (soilOfItem == "Klei")
                     {
-                        oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.67);
+                        oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.67 * (1/0.54));
+                        C_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.67);
                     }
                     else
                     {
-                        oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.81);
+                        oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.81 * (1 / 0.54));
+                        C_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * 0.81);
                     }
                 }
                 else
                 {
-                    oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont);
+                    oM_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont * (1 / 0.54));
+                    C_corr_SoilType.Add((item.Key, soilOfItem), item.Value.OM_Cont);
                 }
             }
 
+            var C_Corr = new Dictionary<string, double>();
+            foreach (var item in C_corr_SoilType)
+            {
+                C_Corr.Add(item.Key.Item1, item.Value);
+            }
+
             var oM_Corr = new Dictionary<string, double>();
             foreach (var item in oM_corr_SoilType)
             {
@@ -899,7 +926,8 @@ namespace FarmMapsAPI.Carbon
                     foreach (var field in cropAreaField1.Where(x => x.Key.Item2 == loopYear))
                     {
                         var valueList = new List<ColumnValue>();
-                        var result = parameterSet.LayerDepth * bulkDens[field.Key.Item1] * oM_Corr[field.Key.Item1] * 0.54; //carbon_organicmatter_factor
+                        //var result = parameterSet.LayerDepth * bulkDens[field.Key.Item1] * oM_Corr[field.Key.Item1];// * 0.54; //carbon_organicmatter_factor
+                        var result = parameterSet.LayerDepth * bulkDens[field.Key.Item1] * C_Corr[field.Key.Item1];// * 0.54; //carbon_organicmatter_factor
                         foreach (var crop in field.Value)
                         {
                             valueList.Add(new ColumnValue(crop.Key, result));
@@ -1708,7 +1736,7 @@ namespace FarmMapsAPI.Carbon
                 var iniValue = item.Value.SingleOrDefault(x => x.Key == "IniCcontent")?.Value ?? 0;
                 var balanceValue = item.Value.SingleOrDefault(x => x.Key == "Balance")?.Value ?? 0;
 
-                var resultOmIni = iniValue / 0.54; //carbon_organicmatter_factor
+                var resultOmIni = iniValue;// / 0.54; //carbon_organicmatter_factor
                 var resultCo2 = balanceValue * (44.0 / 12.0);
 
                 item.Value.Add(new ColumnValue("OM_ini", resultOmIni));
@@ -1727,7 +1755,7 @@ namespace FarmMapsAPI.Carbon
                     var greenManure = item.SOC_CarbonGreenManure;
                     var compost = item.SOC_CarbonCompost;
 
-                    item.OM_ini = iniValue / 0.54; //carbon_organicmatter_factor
+                    item.OM_ini = iniValue;// / 0.54; //carbon_organicmatter_factor
                     item.CO2seq = balanceValue * (44.0 / 12.0);
 
                     var emision = -1 * (manure + residues + greenManure + compost - balanceValue);
@@ -1781,7 +1809,7 @@ namespace FarmMapsAPI.Carbon
                     var resultBal = sumBal / farmArea.Total_crop_area;
                     var resultIni = sumIni / farmArea.Total_crop_area;
                     var resultiniCc = sumInicc / farmArea.Total_crop_area;
-                    var resultOm_Ini = resultiniCc / 0.54; //carbon_organicmatter_factor
+                    var resultOm_Ini = resultiniCc;// / 0.54; //carbon_organicmatter_factor
                     var resultCo2 = resultBal * (44.0 / 12.0);
                     var resultCo2Tot = resultCo2 * farmArea.Total_crop_area;
 
@@ -1828,7 +1856,7 @@ namespace FarmMapsAPI.Carbon
             var soilPropertiesField = new Dictionary<string, SoilPropertyType>();
             foreach (var field in farmInput.CropFields)
             {
-                soilPropertiesField.Add(field.Name, new SoilPropertyType { OM_Cont = field.SoilProperty.OM_Choice.ToLower() == "c" ? field.SoilProperty.OM_Const.Value * 1.85185 : field.SoilProperty.OM_Const.Value, Clay_Content = field.SoilProperty.Clay_Content.Value, OM_Corr = field.SoilProperty.OM_Const.Value <= 20 ? field.SoilProperty.OM_Const.Value : 0, Depth10 = field.SoilProperty.Depth10.Value, Depth = field.SoilProperty.Depth });
+                soilPropertiesField.Add(field.Name, new SoilPropertyType { OM_Cont = field.SoilProperty.OM_Const.Value, Clay_Content = field.SoilProperty.Clay_Content.Value, OM_Corr = field.SoilProperty.OM_Const.Value <= 20 ? field.SoilProperty.OM_Const.Value : 0, C_Cont = field.SoilProperty.C_Const.Value, C_Corr = field.SoilProperty.C_Const.Value <= 20 ? field.SoilProperty.C_Const.Value : 0, Depth10 = field.SoilProperty.Depth10.Value, Depth = field.SoilProperty.Depth });
             }
 
             return soilPropertiesField;
@@ -1841,7 +1869,7 @@ namespace FarmMapsAPI.Carbon
             {
                 foreach (var item2 in item.Value)
                 {
-                    soilPropSoilType.Add((item.Key, item2), new SoilPropertyType { Bulk_Density = soilPropertiesField[item.Key].Bulk_Density, Clay_Content = soilPropertiesField[item.Key].Clay_Content, OM_Cont = soilPropertiesField[item.Key].OM_Cont, OM_Corr = soilPropertiesField[item.Key].OM_Corr }); // soilPropertiesField[item.Key]);
+                    soilPropSoilType.Add((item.Key, item2), new SoilPropertyType { Bulk_Density = soilPropertiesField[item.Key].Bulk_Density, Clay_Content = soilPropertiesField[item.Key].Clay_Content, OM_Cont = soilPropertiesField[item.Key].OM_Cont, OM_Corr = soilPropertiesField[item.Key].OM_Corr, C_Cont = soilPropertiesField[item.Key].C_Cont, C_Corr = soilPropertiesField[item.Key].C_Corr }); // soilPropertiesField[item.Key]);
                 }
             }
             return soilPropSoilType;
diff --git a/Models/CarbonRequest.cs b/Models/CarbonRequest.cs
index 94f4faf..515a27d 100644
--- a/Models/CarbonRequest.cs
+++ b/Models/CarbonRequest.cs
@@ -36,6 +36,7 @@ namespace CarbonService.Models
     public class SoilProperty
     {
         public double? OM_Const { get; set; }
+        public double? C_Const { get; set; }
         public string OM_Choice { get; set; }
         public double? Clay_Content { get; set; }
         public bool? Depth10 { get; set; }
diff --git a/Models/SoilPropertyType.cs b/Models/SoilPropertyType.cs
index 1b04a05..328e422 100644
--- a/Models/SoilPropertyType.cs
+++ b/Models/SoilPropertyType.cs
@@ -8,6 +8,8 @@ namespace FarmMapsAPI.Carbon.Models
     {
         public double OM_Cont { get; set; }
         public double OM_Corr { get; set; }
+        public double C_Cont { get; set; }
+        public double C_Corr { get; set; }
         public double Bulk_Density { get; set; }
         public double Clay_Content { get; set; }
         public int? Depth { get; set; }