code: public static String getFstPdate(Map data, String defValue) {
          ArrayList<HashMap<String, String>> events = getBucket(data, "management").getDataList();
          Event event = new Event(events, "planting");
          return getValueOr(event.getCurrentEvent(), "date", defValue);
      }
docs: Get the first planting date from given data set.
  
  @param data The experiment data holder
  @param defValue The value used for return when planting date is unavailable
  @return The planting date