Humic substances are carbon-rich materials formed primarily through microbial decomposition of dead plant matter, a process called humification, carried out by bacteria and fungi. These substances are found in soils, compost, peats, water, and various types of coals, which differ based on the conditions of peat formation, such as vegetation, climate, and geological processes.

Humic substances create beneficial stress (eustress) in crops, enhancing photosynthesis, root development, and nutrient and water uptake, helping plants better withstand stress and boosting productivity. They also improve soil health by promoting root exudates that stimulate microbial activity, increase soil water content, and enhance soil structure. These microbes add carbon to the soil when