Corn seed environment. Competing microbes

Biology of the corn plant is complex, with genes turned on to produce complex products in timely fashion to result in grain production.  Even more complex are the interactions among the microbes surrounding the germinating corn seed in the field.  These organisms compete with each other for nutrition from the dead organic matter as well as the live new root tissue.  The multiple bacteria species oppose each other chemically and fungi produce antibiotics to gain advantage over bacterial and other fungal species.
 
Corn plants not only produce defensive chemicals to fight off potential pathogens, but also encourage favorable microbes.  One example was described in a recent publication:(PloS ONE Feb. 20,2017) in which the DIMBOA exuded from corn roots not only inhibits soil insects but also favors a beneficial bacterium species, Psuedomonas putida, allowing it to outcompete with potential corn pathogens surrounding the root tissue.  DIMBOA is a common biocide produced in corn that not only inhibits insects like corn borers in young stalks it also affects micro-organisms.
 
Some of the bacterial population can fix nitrogen, making nitrogen available to plants but also to other microbes for their metabolism.  And there is competition for that as well. One of the advantages of the corn plant comes from the roots quickly going deeper than the upper soil surface where the organic matter and microbes are most prevalent.  This not only favors high quality seed but also corn genotypes that have fast early growth.
 
That corn field that looks like only a lot of dirt immediately after planting has a lot of unseen activity.