Soil databases

Background

Computer simulation models are now being widely used for impact assessment studies and for supporting policy decisions at different temporal and spatial scales.  However, for application of these models detailed data bases are required that cover large regional areas. Unfortunately, this information is rarely available.  The International Soil Reference and Information Centre (ISRIC) has developed a series of detailed soil databases, early versions of which have been converted for use in agricultural impact model applications.  Accurate soil data that represent local soil conditions are important for the simulation of the soil water and nitrogen balances, especially for rainfed conditions where water is limiting.  Soil data can be extremely variable across space, and scaling up from point-based simulations to grid-based simulation provides considerable challenges related to input data.  There is now a WISE Version 3.1 database, and converting this into model format would allow many more additional soil profiles to be utilized, that may be more representative of the local conditions.

Objectives

The objective is to obtain location-specific estimates of selected top-soil and sub-soil properties and derived soil quality indicators of importance to crop production and natural resource management.

Activities

Once the latest WISE database has been obtained and its data accessed, the work involves implementing conversion equations that relate the WISE soil attributes to crop model specific soil parameters.  Different options are being evaluated that can be used to convert soil texture into soil water holding characteristics.  Routines are being developed to output soil profile data in a generic format, along with data quality control procedures for specific soil parameters.   Options are also being explored to develop generic soil profiles based on the current profiles of the WISE soil data base.

Outputs

• An updated soil profile data base that can be used for extended crop model applications based on the WISE soil data base.
• Improved procedures for converting WISE soil attribute data into crop model specific soil parameters.
• A secondary soil data base that contains more generic soil profiles based on the detailed soil profiles of the WISE soil data base.
• Documentation describing the analytical methods that were used, the strengths and weaknesses of the updated database and suggestions for further enhancement.

Partners

Timeframe