code: public static ArrayList<HashMap<String, String>> computeSoilLayerSize(ArrayList<HashMap<String, String>> soilsData) {
  		float deep = 0.0f;
  		ArrayList<HashMap<String, String>> newSoilsData;
  		newSoilsData = new ArrayList<HashMap<String, String>>();
  
  		for (HashMap<String, String> currentSoil : soilsData) {
  			// create a new soil with reference parameters
  			HashMap<String, String> newCurrentSoil = new HashMap<String, String>(currentSoil);
  			// Specific for stics soil data representation
  			newCurrentSoil.put(LayerReducer.SLLB, new Float(parseFloat(currentSoil.get(LayerReducer.SLLB)) - deep).toString());
  			deep = parseFloat(currentSoil.get(LayerReducer.SLLB));
  			newSoilsData.add(newCurrentSoil);
  		}
  		return newSoilsData;
  	}
docs: Compute soil layer thickness
  
  @param soilsData
  @return