code: public static String getEventDateVar(String event, String var) {
          var = var.toLowerCase();
          if (event == null || var.endsWith("date") || var.endsWith("dat")) return var;
          if (event.equals("planting")) {
              var = "pdate";
          } else if (event.equals("irrigation")) {
              var = "idate";
          } else if (event.equals("fertilizer")) {
              var = "fedate";
          } else if (event.equals("tillage")) {
              var = "tdate";
          } else if (event.equals("harvest")) {
              var = "hadat";
          } else if (event.equals("organic_matter")) {
              var = "omdat";
          } else if (event.equals("chemicals")) {
              var = "cdate";
          } else if (event.equals("mulch-apply")) {
              var = "mladat";
          } else if (event.equals("mulch-remove")) {
              var = "mlrdat";
          }
          return var;
      }
docs: Renames a date variable from an event