The objective of the SINFO project is to describe the existing system and to propose a new method evolution for the MARS Crop Yield Forecast Sing System (MCYFS). The work consisting in:
- Rewriting the Pedo Transfer Rules (PTR) according to the new nomenclature;
- Redefinition of new Soil Physical Groups and their parameters;
- Redefinition of new Rooting Depth classes;
- Re-evaluation of CGMS Suitability Criteria;
- New evaluation of Soil Suitability Criteria;
- Generation of soil parameters with FAO (Food and Agriculture Organisation) soil map.
The soil data are used to determine soil input variables to the agrometeorological model giving information about the soil types geographical location and the soil properties which are needed to simulate the crop growth during the year. The main soil properties are soil depth aiming at defining the potential rooting depth, and water retention properties giving through soil physical groups. Each STU has one soil physical group defining the available water capacity (AWC). The AWC is a static soil characteristic and gives the amount of water between field capacity (wet soil) and wilting point (no water available for plants anymore) per unit length rooting depth. Multiplication of AWC and rooting depth gives the maximum available water which a soil can supply to a plant.
It should be noted that the rain fed crop yields of the CGMS are more sensitive to the rooting depth than to the soil physical group (van der Goot, 1998). The CGMS stores these data in the tables ROOTING_DEPTH and SOIL_PHYSICAL_GROUP. Further, the soil map is used as a ‘land use probability map’ to define which crops have to be included in the simulation for a given soil unit. Ideally, this decision would be taken on the basis of actual land-use information, but a European wide detailed classification of land cover is not available. Hence within the CGMS the decision is simply based on the soil suitability of the different crops: if at least part of the soil mapping unit (one or more STU’s) is deemed appropriate then the simulation will be performed. The result of this strategy is that the yield figures produced by the CGMS are assessed for suitable soils only.
Suitable soils are determined per crop group on the basis of crop growth limiting properties of these soils. The limiting soil properties are for instance slope, texture, agriculture limiting phase, rooting depth, drainage, salinity and alkalinity. The slope, texture and phase data can be obtained directly from the soil database, while others like rooting depth, drainage conditions, salinity and alkalinity have to be derived from basic soil properties using pedotransfer rules.
The suitable STUs and the percentage of the suitable area of SMUs and NUTS regions are available in the tables SUITABILITY, SMU_SUITABILITY and NUTS_SUITABILITY. Because a SMU and a NUTS region can consist of more than one STU the percentage suitable area must be calculated.