Like most plants, soybeans pair up with soil fungi in a symbiotic mycorrhizal relationship. In exchange for a bit of sugar, the fungus acts as an extension of the root system to pull in more phosphorus, nitrogen, micronutrients, and water than the plant could on its own.
source https://www.lifetechnology.com/blogs/life-technology-science-news/genes-controlling-mycorrhizal-colonization-discovered-in-soybean