Some kind of plants (e.g. Leguminoses) are forming a symbiosis with soil bacterias of the species Rhizobium. The roots are forming so-called Rhizobii in which bacterias are living. So the nitrogen is easier available. Especially young plants are easier getting used to the substrate when Rhizobii are added and the survival rate is higher.
IFP isolated wild strains of Rhizobium and is using these successfully in young plant propagation.
We will gladly inform you in more detail about availability and applicability of our Rhizobia.