CGMS soil Suitability Criteria
Comparison of ESCAPE-rule based suitability maps from SGDBE version 4.0 with land cover map
The comparison revealed that the relationship between actual land cover and suitability maps (see Annex 5, map 7-11) was weak, except in some obvious cases where the absence of intensive agricultural land use coincides with the occurrence of unsuitable soils due to the presence of steep slopes, rock- or peat-covered surfaces, or salt flats. The low proportions of suited soils found in the southern part of the Balkans, the Alps, Scotland, and Norway correspond well with the land cover information. On the other hand, more analysis is required to get an understanding of some results. When looking at the ESCAPE-based suitability maps the proportion of suited soils was relatively low in England, Spain, Latvia and Estonia. Italy as a whole is mapped as suitable for oilseeds, but largely unsuited for root crops. In Norway, Germany, Spain and Greece the shift in suited area from oilseeds to root crops goes in the same direction as in Italy, but in Sweden the shift is in the other direction, while the selection of suitable soils does not change in Finland, Denmark, Russia, Ukraine, Turkey and the countries east and south of the Mediterranean Sea. These apparently arbitrary differences can be interpreted easily on the basis of the criteria. Italy has a lot of sloping land, which is rated unsuited for root crops, but suited for oilseeds. Sweden has no sloping land (according to the soil map), but a lot of shallow soils, which are rated suited for root crops and unsuited for oilseed crops. In countries without steep slopes and without shallow soils, the suitability maps for oilseed rape and root crops are quite similar.
In summary, the existing ESCAPE-based suitability criteria for cereals and grassland lead to estimates of relatively high proportions of suited land in comparison with the land cover map. The application of more severe suitability criteria for oil seeds and root crops in ESCAPE leads to underestimation of suited land in some countries. The ESCAPE rules for root crops correspond largely with the CGMS rules for cereals, but CGMS excludes in addition all soil phases as unsuited, so that the suited area resulting from the ESCAPE rules is larger. The difference leads to clearly more plausible results than the CGMS rules in a few cases: the Netherlands, the Danish Islands, Lithuania, Russia north of the Caspian Sea, Cyprus, north-eastern Spain. In a few other cases it is more difficult to judge which result is better: northern Algeria, the whole of Sweden, southern Finland, boreal Russia and eastern Turkey.