More empirical research is required to better understand whether, and to what degree, markets for phosphorous and potassium might indeed be characterised by imperfect competition, given the relative concentration of natural reserves of these mined products. Given that the model is comparative-static with a medium-term framework, the results shown in this report refer to impacts after adjustments have taken place. Furthermore, the Armington specification of trade flows tends to make the model conservative with respect to the structure of international trade. The empirical basis for some of the model parameters, in particular with respect to the newly introduced fertiliser markets, is weak.