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In order to correctly simulate the crop growth reliable, realistic sowing dates and cycle length are fundamental. Moreover in tropical and sub-tropical regions like South-China two or especially tree cropping cycles are possible. In these regions the knowledge of real crop rotation and the suitable crop calendar (e.g. for early and double season late rice) is fundamental for an accurate yield forecast.

One possible option to find such data is the usage of COPdate (Savin et al. 2007). COPdate stands for Climatically Optimal Planting date. The concept of finding optimal planting dates based on climate data, is implemented in the oracle COPdate package. By running the package for all historical years, the earliest and latest optimal sowing date can be found (sowing date window). By processing a specific year, the optimal sowing date for that year is found. In the operational MCYFS mainly the functions find_sowing_date (for a single year) and sowing_dates_years (for multiple years) are used. Both functions find a sowing date for a specific combination of crop, grid and year, according expert rules.


To be able to run the package in parallel, it is connected to a tasks administration system that should be initialized before running the find_sowing_date and sowing_dates_years functions.

Required objects inside the oracle schema where the COPdata is applied (e.g. CGMS14RUK):

  • COPDATE package
  • MRSDATES package
  • COP_WINDOWS table
  • INIT_TASKS procedure
  • TASKLIST view
  • ADD_PROCESS_LOG synonym
  • SIGNALS synonym
  • TASK synonym
  • TD_KEY_VALUE synonym
  • TD_KEY_VALUES synonym
  • TASKSET sequence
  • PROCESS_COP_OSD_BLK procedure

Required objects inside the assisting oracle schema for administering task (e.g. RUKMAN):

  • SIGNALS package
  • TASK package
  • TD_KEY_VALUE types
  • TD_KEY_VALUES types
  • ADD_PROCESS_LOG procedure


To initialize tasks for COPdate, the INIT_TASKS procedure is used. Five or six arguments are required:

To initialize a single year:

  • task (= cop-sd)
  • initial status (= pending)
  • crop
  • year
  • regime (winter or spring)

To initialize multiple years:

  • task (= cop-sd)
  • initial status (= pending)
  • crop
  • start year
  • end year
  • regime (winter or spring)

If start- and end year are NULL then all the years in the crop_calendar will be initialized for the crop and grid(s). If start- or end year is NOT NULL, then this value will be used as start- resp. end year of the range of years; the other value will be derived from the crop_calendar. If both start- and end year are NOT NULL these values will be used as start- resp. end year of the range of years; only this range will be processed. The start- and end year will be included in the range to be processed. The above procedure fills the TASK_LIST table in the assisting schema (e.g. RUKMAN) which transfers the tasks via views to the various TASKLIST views in the main schema (e.g. CGMS14RUK).

Planting date Rule

- To be completed -

Finding the planting dates

To find optimal planting dates, the functions PROCESS_COP_OSD_BLK for a single year, or PROCESS_COP_SD_ALLYEARS_BLK for multiple years are called. These procedures pick up tasks with phase Pending and of a certain age. They are processed one by one at a time. When picking up a task, its phase is updated to In progress. In case of an error, the phase is updated to Error. When a sowing date is found, the phase is updated to Resulted and the found sowing date is updated in the CROP_CALENDARS table. When no sowing date is found, the phase is update to No result and a new tasks is created with phase Pending. When no more tasks of a certain age and with phase Pending are found, the processing is aborted.

The use and administration of the tasks allows that the COPdate can be called in parallel since only pending tasks of a certain age are processed (thus ignoring just newly created tasks).