What is Soil Aggregation and explain its beneficial role

Some organisms may play a beneficial role indirectly by creating better soil physical conditions e.g., by improving soil aggregation.  You have read about the role of earthworms in soil granulation. Plant roots also promote soil aggregation with the help of their decay product. Gum or polysaccharides produced by certain microorganisms also cause soil aggregation.  Azotobacter, Baijerinckia and Rhizobium are examples of gum producing bacteria.