Fertile soils are usually productive but not always and, productive soils are not always fertile soils.
Soils with the highest natural yield from soil fertility must not produce the highest yield from additional investments such as from seeds, fertilizer, biocides, soil tillage and irrigation. In view of modern ways of soil use it is necessary to distinguish the yields achieved solely from natural soil properties, and yields achieved from soil properties which transform investments into yields. That means that soil fertility and soil productivity are terms which designate different properties of soils.
Mainly low income regions of the world can not pay for investments into soils. Their prosperity is dependent on soil fertility. Opposite to this rich regions can make use of the transformation properties of soils for yields and services by investments.
There will be an enormous pressure on the natural resource soil in the future for which we have to define the status of soils in view of their potential for use on different economic levels.