Biostimulants come from nature. They are small molecule organic active substances extracted by biotechnology without artificial chemical synthesis, and can act directly on plants. Internationally used biostimulants are classified into: microorganisms, humic acid, alginic acid, amino acids, chitosan, and inorganic salts.

Plant growth regulators: This is a special class of compounds that can specifically affect the growth and development process of plants. By regulating the physiological mechanisms within the plant, these products can promote or inhibit specific growth stages, thereby achieving the purpose of adjusting plant morphology and improving stress resistance.

The relationship between biostimulants and fertilizers ‌ is mainly reflected in their complementary and synergistic effects in agricultural production. Biostimulants are a new type of fertilizer. Although they do not directly provide nutrients, they can stimulate the physiological and biochemical processes of plants

Fulvic acid: It is the water-soluble part with the smallest molecular weight and the highest content of active groups in humic acid. Its functional groups interact with each other, reflecting a variety of specific physical and chemical properties. After entering the plant body, it can play a variety of physiological functions