“The formation of root hairs greatly increases the root’s surface area.
Rye (Secale cereale) has about 13,000,000 roots with a surface area of
235 square meters, and 14,000,000,000 root hairs with a surface area of
400 square meters in 1/22 of a cubic meter of soil. [. . .] The surface
area of the underground portions is thus 130 times as large as that of
the above-ground portions” (Jurzitza 1987, 28). (https://www.ecofarmingdaily.com/build-soil/humus/what-is-humus-made-of/)

Studies show that 10 times more bacteria live in the rhizosphere than in the bulk soil. (https://www.nature.com/articles/ismej2008103)

Like a human mother passes beneficial microbes to her child during birth, plants place beneficial microbes on and in the seeds of their offspring to get them off to a good start. Seed treatments are hindering nutrient cycling.