Yes, soil can chemically communicate with nearby soils through plant root networks and mycorrhizal fungi, which transfer signals and compounds between connected plants, indirectly influencing surrounding soil chemistry.

In my experience, one would say that communication is limited to biota but I may be wrong!! For example is a nitrate gradient in soil a communication to plant roots?

It is possible, through microbial activity (mycorrhizal fungi) through its network and plant root cells due to the enzymatic system of the roots.