Humus is produced by biodegradable organisms such as lignin, which is difficult to be degraded further by microbial degradation. Its specific performance and structure depend on the specific conditions of a given sample from water or soil sources.
However, although the source of humus is different, the performance is very similar. Humic acid can be divided into three main parts in soil and sediment: Humic acid (HA), fulvic acid (FA) and humin (HM). Where HA is soluble in base, but insoluble in water and acid; FA is both soluble in alkali and soluble in water and acid; And HM is soluble in dilute alkali, insoluble in water and acid. It can be separated from the metal ions in the water, which is beneficial to the transmission of nutrient elements to the crops, and can improve the soil structure, which is conducive to the growth of crops. It has the function of exchange, adsorption, complexation and chelation with metal ions; As a polyelectrolyte in dispersive system, it has the function of coagulation, glue solution and dispersion. Humic acid molecules have a certain number of free radicals, which have physiological activities.