The present invention relates to a granular fertilizer formulation capable of increasing the water retention capacity of soil. In particular, the present invention relates to a granular fertilizer formulation, in the form of granules, said granules consisting of a fertilizer based on nitrogen (N), or nitrogen-phosphorous (NP) and/or nitrogen-phosphorous-potassium (NPK) and a polymer of vegetable origin selected from the group of water-soluble derivatives of guargum and capable of increasing the water retention capacity of a crop soil. Furthermore, the present invention relates to a process for the preparation of said formulation comprising - finely grinding the raw materials of the formulation; then adding and mixing them at room temperature in a mixer for powders, adding water in an amount sufficient to obtain a homogeneous fluid paste of particles; - directing and making said fluid paste flow on a belt, a fluid bed, in movement, wherein the particles rotate and become stratified so as to form granules/micro
