Humic acid fertilizer is an efficient and environmentally friendly type of fertilizer that plays a significant role in agricultural production. The following are the main effects and functions of humic acid fertilizer:

Improving soil fertility

Humic acid fertilizer can increase the organic matter content of the soil, improve soil structure, enhance the soil's water and nutrient retention capabilities, and improve the soil's acid-base buffering capacity. 1 These functions effectively enhance soil fertility and promote plant growth.

Promote plant growth

The humic acid in humic acid fertilizers can promote the development of plant roots, increase the plant's ability to absorb water and nutrient elements, enhance the plant's stress resistance, and thereby promote plant growth 1. In addition, humic acid can also stimulate physiological metabolism and promote growth and development .

Improving crop yield and quality

The nutrient elements in humic acid fertilizers can enhance the photosynthetic efficiency of crops, increase crop yield and quality  Humic acid can also increase the utilization rate of various nutrient elements in the soil, reduce fertilizer loss, and improve fertilizer efficiency.

Improving soil environment

The organic substances in humic acid fertilizers can improve the soil environment, inhibit the growth of harmful microorganisms in the soil, and reduce soil pollution. At the same time, humic acid can also promote the micro-ecological balance in the soil and enhance the soil's self-purification ability. Moreover, humic acid can also loosen the topsoil layer, disrupt the accumulation of salt, reduce the salt content in the surface soil, and play a role in salt isolation. 

Enhancing the efficacy of other fertilizers

Humic acid fertilizer has an enhancing effect on phosphate fertilizer and potassium fertilizer. The aromatic rings, hydroxyl groups, carboxyl groups and other acidic functional groups in humic acid can react with phosphorus elements, converting them into soluble phosphorus, thereby increasing the activity of phosphorus elements. Similarly, the functional groups in humic acid can also absorb and store potassium ions, increasing the utilization rate of potassium fertilizer by 348%.

In conclusion, humic acid fertilizers have significant effects in enhancing soil fertility, promoting plant growth, increasing crop yields and quality, and improving soil environment. Therefore, in agricultural production, the rational application of humic acid fertilizers can effectively increase the yield and quality of crops, and is also beneficial for protecting the environment and promoting sustainable agricultural development.