Home > Rewriting PedoTransfer Rules > Alkalinity rule > Current alkalinity rule

• Introduction
• Generation of soil parameters with FAO soil map
• Verification and update of WRB-codes
• Rewriting PedoTransfer Rules
• Uses of soil names
• Salinity rule
• Alkalinity rule
• Current alkalinity rule
• Available information
• Adapted alkalinity rule
• Chemical Toxicity rule
• Drainage rule
• Redefinition of new Soil Physical Groups
• Redefinition of new Rooting Depth classes
• CGMS soil suitability criteria
• Summary
• References
• Annex

Rewriting PTR salinity, alkalinity, chemical toxicity and drainage based on the wrb-standard

Description of the current PTR used to derive alkalinity

The current rule used for estimating alkalinity in CGMS is described in Table 4-8.

Table 4-8: Current alkalinity rule used in CGMS

In the current rule, alkalinity is estimated as strong only if the soil is a Solonetz (FAO-UNESCO 1974 legend).

Alkalinity of soil has two effects on crops. The first one is a toxicity effect due to the Sodium ions. The second effect is an indirect one due to a massive or columnar structure and a lower permeability of the soil which are unfavourable conditions for rooting and ploughing. It is measured by the ratio between the exchangeable sodium and the exchange capacity, called ESP.