What type of farming would be most appropriate and why???

Question

..for...

Beligium...

Mediterranean Greece...

Southern Italy....

Southern Portugal......

Answer 1

Sustainable agricultural practices would be the best for them all.  That means the right crops in the right rotations and the right intensity of use for the variety of landscapes in each of the regions.  

I don't think you want this answer though.  I think you want to know which specific crops are the best for each area.  The reality is the land is so varied even within each of the regions mentioned that there are a large number of crops and ways to approach farming that will work in each of them.