Home > Data and statistics, Global Futures for Agriculture, Simulation modeling > Crop model calibration with yield trial data: Dealing with missing soil data

Crop model calibration with yield trial data: Dealing with missing soil data

A previous blog post discussed how to deal with missing weather data when calibrating a crop model with incomplete yield trial data. A further common problem associated with the use of field trial data from crop breeders for the purpose of calibration of the DSSAT-SUBSTOR  potato model is missing or insufficient soil data.

The DSSAT soil water and nutrient routines require information of the soil found at the site, consisting of a broad range of soil physical and chemical parameters taken from different depths of the soil. The soil data provided along with yield trial data, however, often only consists of information on pH, nutrient availability, organic matter content and soil texture, taken from a sample at one single depth. In this situation, how can we obtain a complete soil profile to be used in DSSAT?The approach suggested and agreed upon at crop model calibration workshop of the Global Futures for Agriculture Project relies upon the ISRIC-WISE Global data set of derived soil properties on a 0.5 by 0.5 degree grid.

In order to obtain a soil profile for a particular site, we proceed as follows:Go to the HarvestChoice Grids Database. This database allows to identify the WISE soil profiles which correspond to a particular place on the earth surface.

  1. Drop the red “droppr” to the point where your site is located.
  2. You get a selection of soil profiles which possibly correspond to the soil actually present in your pixel.
  3. Look up the profiles in the WISE database and choose the one you deem most adequate for the local conditions. This choice may be supported by the soil analysis data you have. The most important variables for the choice are soil texture and pH.
  4. Copy the profile chosen to your DSSAT soil database.
  5. Using DSSAT’s soil profile editor, edit the soil profile chosen to include the soil information you have from the site. The program can recalculate a number of variables. Delete the original entries and recalculate.
  6. Use this soil profile for you experiments in DSSAT.

Once again, the use of this external data is far from ideal. However, it allows to get a reasonable approximation to the actual soil conditions at the experimental site. Moreover, if the experiment had no water or N stress, the soil data is less relevant.

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