Question

What makes the soil smell so good after the rain?

Answer 1

The earthy fragrance generated when rain falls on dry soil is known as petrichor. The term comes from the Greek words petra, which means "rock," or petros, which means "stone," and chr, which refers to the fluid that flows through the veins of the gods in Greek mythology. Air from the pores creates tiny bubbles that rise to the top and release aerosols when a raindrop lands on a porous surface. The smell, as well as germs and viruses from the soil, are carried by these aerosols. Raindrops that travel slowly generate more aerosols, which explains why petrichor is more frequent after light showers.

Complete answer:
The usual earthy fragrance of damp soil after rainfall is known as "petrichor", and one of its primary components is an organic molecule known as geosmin, which lingers around moist soil.
Geosmin is derived from the ancient Greek words "geo" (earth) and "osme" (smell).
Geosmin is produced by soil microorganisms, principally bacteria with the scientific name Streptomyces. These bacteria are common in soil and are among nature's finest chemists, producing a wide spectrum of chemicals (known as specialised metabolites) from which many antibiotics are derived.
The gene for producing geosmin is found in all streptomycetes, indicating that it plays a significant role.

Note:
Geosmin has the potential to repel predators while also attracting creatures that spread spores. Geosmin repels fruit flies, making them less inclined to consume Streptomyces -infested materials. Geosmin is thought to attract small soil creatures, which then become covered with spores and disseminate them throughout the soil. Geosmin is also responsible for off-tastes in water, wine, and freshwater fish, and removing its odour has commercial value for some.