Not just dirt! What are the components of your soil? How do we make soil? Or better yet, How is soil made? Who makes soil? Is sand soil? What is UPCG’s parent soil? Dirt, dust, mud, earth, grit…hmmm…lot’s to think about.
Nitrogen gas is drawn into the earth by means of rhizobia a bacteria that works symbiotically with the roots of certain plants. Legumes, beans, peas and vetch produce nodules that collect nitrogen with the work of rhizobia who convert it into ammonia. For fascinating reading and for the citizen scientist gardener cut and paste the following link into your browser.
Source: Boundless. “The Legume-Root Nodule Symbiosis.” Boundless Microbiology Boundless, 26 May. 2016. Retrieved 7 Apr. 2017 from https://www.boundless.com/microbiology/textbooks/boundless-microbiology-textbook/microbial-ecology-16/microbial-symbioses-196/the-legume-root-nodule-symbiosis-993-7114/