humic acid cognitive1. Sources and classification of humic acid

Humic acid is generally considered to be a complex mixture of hydroxybenzene carboxylic acids with non-uniform molecular weight.Lignite, peat and leonardite have high humic acid content and are the main sources of humic acid extraction.The extraction rate of humic acid was highest in leonardite, followed by lignite and peat.
According to the traditional method of soil science, humic acid can be divided into humic acid, fulvic acid and humin.Humic acid is also divided into 3 categories: do not dissolve in alkaline solution, can dissolve in acidic solution called black humic acid;Only dissolved in alkaline solution, can not be dissolved in acidic solution is called brown humic acid; can be dissolved in both alkaline and acidic solutions called Fulvic acid.

2. Characteristics of humic acid

Humic acid is a kind of high molecular organic acid which is composed of aromatic group and many functional groups. It has good physiological activity, absorption, complexation, exchange and other functions .Humic acid can promote the formation of soil aggregates, enhance soil permeability, enhance soil water and fertilizer retention ability;It can also stimulate the growth of plants, enhance their ability to resist drought, cold, diseases and pests, and improve the quality of agricultural products.Stimulate the activities of soil microorganisms, improve the sufficient carbon and nitrogen elements, improve the living environment of microorganisms, and increase the number of soil beneficial microorganisms and soil enzyme activity.

3、Classification of humic acid fertilizers

humic acid cognitiveAccording to different techniques, humic acid fertilizers are generally divided into the following categories:
— humate (potassium, sodium, calcium, magnesium, ammonium, boron, etc.)
— humic acid derivatives (nitrohumic acid, nitrohumate, humic acid complex, etc.)
— humic acid- resin copolymer (humic acid super absorbent resin, humic acid soil improver)
— fulvic acid fertilizers (fulvic acid drought resistance agent, fulvic acid nutrient liquid fertilizer, fulvic acid granular compound fertilizer)
–controlled release humic acid single fertilizer (controlled release humic acid urea, controlled release humic acid phosphate fertilizer)
— humic acid organic and inorganic compound fertilizer (various special fertilizers)
According to different application modes, humic acid fertilizers can be divided into the following categories:
— fertilizer for seed dipping and root dipping (sodium humate, potassium humate, fulvic acid antidrought agent)
— foliar spraying or root flushing fertilization (sodium humate, potassium humate, fulvic acid drought resistance agent, fulvic acid nutrient liquid fertilizer, humic acid liquid fertilizer)
— field base fertilizer or topdressing fertilizer (humate, humic acid derivative, controlled release humic acid single fertilizer, humic acid organic and inorganic compound fertilizer, humic acid biological fertilizer)
— soil improvement fertilizer (humic acid super absorbent resin, humic acid soil conditioner)