2023, Vol. 8, Special Issue 4

Humic acid is organically derived organo-chemical which is multi-structural, multi-functional, ubiquitous whose demand to enhance soil quality is very low compared to bulky manures. There are various sources of humic acid whose composition and characteristics varies accordingly source, place, time etc. The global demand of organic produce increases 21% annually whereas in Indian sub-continent as well India increases thirty-six and 51% respectively. The bulky application of organic manure is the major constraint in terms of availability and applicability of input with improved technology. Thus, organic manure though with best nutritional qualities should be ruled out for production in larger areas as it is quite tedious along with high input cost per unit production.

The overview under the presentation is made for the humic acids derived from Lignite coal which is high in hydro-carbon and sulphur compared to other sources (compost, peat, forest land, agricultural land, river and lakes) high in nitrogen and oxygen. Calorimetrically, humic acids obtained from the lignite coal is yellow, black and brown colored which is extracted conventionally for the humic acids (via alkali followed by acid treatment). Chemical characterization of the lignite coal derived humic acids shows high E2:E3, E3:E5, E4:E6 with major carboxylic, hydroxylic, phenolic, alcoholic, methoxylic functional groups and high surface area to chelate and complexates with the metals to from organo-metallic. Application of humic acid in the soil had been reported to increase aggregate stability (i.e., higher the doze of humic acid higher the size of aggregate revealed to be stable). Chemically, less buffering with high available nutrient and biologically the increase of aerobic bacteria compared to anaerobic has been reported. The nutrient content along with yield also stated to increase with a common myth that humic acid is acting as a bridge between soil surface and desorbing behavior of element esp. phosphorous. Thus, Lignite coal derived humic acid are highly aromatic to improve soil health, reduces loss of nutrient in agricultural crop production.