Application Of Humic Acid Fertilizer in Plants

The application of humic acid fertilizer in plants is an efficient and environmentally friendly organic fertilizer, which can effectively improve soil quality, promote plant growth, improve yield and quality, reduce the risk of pesticide use, and increase crop resistance and disease resistance.

 

 

1. Humic acid stimulates plant root growth and promotes nutrient absorption

In the process of plant growth, the stimulation of humic acid is the driving force to promote the growth of plant roots. This effect is concentrated in the significant which increasing in the number and length of roots. The study found that the number of lateral roots of tomato plants treated with humic acid was more than that of ordinary plants, with an increase of about 150%~264%, and the length increase was as high as 405%~2280%. The effect of humic acid on plants is mainly a stimulatory response similar to the use of large amounts or low-dose auxins, and is closely related to some biostimulants such as cell kininases. After the use of humic acid, the biochemical activity of plants was further improved, the root system was affected by similar auxin stimulation, the production of auxin and endogenous cell kinins increased, thereby changing the permeability of the cytoplasmic membrane, the synthesis of plant proteins was accelerated, the cell growth was accelerated, the growth rate of plant roots was more significant than that of ordinary plants, and the yield was greatly increased.

 

Humic acid can promote nutrient absorption in plant roots, which is usually manifested by nitrate absorption. Humic acid can not only promote the expression of nitrate absorption and assimilation-related genes in plant roots, but also improve the environment in the root system and accelerate the rate of nitrate absorption. It is pointed out that humic acid can regulate the uptake, transfer and assimilation of nitrate, thereby accelerating the uptake and utilization of nitrate nitrogen by plant roots. In addition, humic acid itself is also a nutrient, which can also be absorbed and utilized by plant roots. Humic acid, which is dominated by small molecular weight substances, has a higher chance of reaching the plasma membrane of higher plants, and is easier for plants to absorb and utilize.

 

2. Humic acid can improve plant stress tolerance and speed up plant growth

Plant growth is easily affected by biological or abiotic stress, and humic acid can effectively alleviate this process, provide necessary protection for plant growth under adversity stress by improving external physiological morphological characteristics, and can play a role in preventing oxidative stress, which is of great significance to plant ecological security. Many studies have found that when plants are subjected to adversity (such as moisture, heavy metals, temperature or salt, etc.), humic acid can stimulate enzyme and protein synthesis in plant organs, enhance the activity of various enzymes related to reactive oxygen species metabolism (such as superoxide dismutase, peroxidase and catalase, etc.), reduce plasma membrane permeability and malondialdehyde levels, reduce reactive oxygen species content, and alleviate the degree of membrane lipid peroxidation. Under this circumstance, the growth rate of plants is reduced by the influence of the external adverse environment, the permeability of cell membranes is maintained, and the performance of plants against disasters is improved.

 

In terms of changing plant stress tolerance, the role of humic acid is not only to change its physiological characteristics and external morphology, but also to improve plant stress resistance by adjusting the plant growth environment. For example, under salinity stress, humic acid can improve soil conductivity, promote seedling growth, and increase the expression level of chlorophyll inside plants. Humic acid colloids are easily affected by the release of organic acids from the root system, decomposing sufficiently small individual growth regulatory molecules, which reach the cell membrane through the cell wall matrix, and produce benign intervention on plant gene expression and enzyme activity.

 

3. Humic acid can promote fertilizer and soil nutrient conversion, and accelerate plant growth

Humic acid can directly react with fertilizer or soil nutrients, thereby transforming nutrient form, improving its utilization efficiency, making it easier for plants to absorb and utilize, and ultimately promoting plant growth. Humic acid can regulate soil nutrient morphology, form a competitive relationship with phosphate at the adsorption site of soil nutrient surface, and reduce the adsorption of phosphate on mineral surface. Humic acid can combine with soil calcium ions to reduce the formation of Ca-P precipitation and strengthen the effect of fertilizer or soil phosphorus. It was found that humic acid could combine with soil potassium ions to improve soil adsorption resistance. So it was believed that humic acid had a considerable regulatory effect on the effectiveness of soil potassium. In addition, there are many acidic groups inside humic acid, which can improve the soil pH value and enhance the effectiveness of soil trace elements such as Zn, Mn, Cu and Fe.

 

Humic acid secretes humic acid-urea complex under the reaction of its own phenolic hydroxyl, carboxyl group and uric acid amide group, which has high stability and good inhibitory effect on urea decomposition, which can improve nitrogen utilization, regulate urea performance, and make it long-term and slow-acting. In addition, the ammonium nitrogen in fertilizers can be fixed by humic acid to form chemicals or bound forms including indole, amide-peptide and pyrrole. Humic acid has a fixed and adsorptive effect on potassium in fertilizer, or directly reacts with it to generate potassium humate, which is a colloidal compound with less chance of loss with water, and the slow-release property of potassium fertilizer is improved.

 

4. Humic acid has a regulatory effect on enzyme and microbial activity in soil, accelerating plant growth

Among the soil humus components, humic acid is a very important part, and its carbon form is relatively stable, which is of great significance to microbial activity. Humic acid can stimulate the activity of enzymes and microorganisms in the soil, preserve fertilizer nutrients, and promote plant growth. Taking urease as an example, the influence of humic acid is concentrated in soil enzyme activity. It is believed that the initial addition of humic acid can not only inhibit soil urease activity, retard urea hydrolysis, and reduce ammonia volatilization. In the later stage, it can maintain the stability of urease activity, promote the conversion of urea to ammonia at a relatively stable rate, and accelerate plant growth. The reason why humic acid inhibits urease activity is mainly due to the high content of unsaturated bonds, which can prevent the oxidation of sulfhydryl groups, -SH and other active functional groups. At the same time, humic acid can also chelate Cu with Hg2 urease sulfhydryl inhibitors. When soil is rich in organic matter, humic acid also has a strong inhibitory effect on urease, N-acetylglucosamine and acid phosphatase activities.

 

Humic acid has a great influence on the number of microorganisms in the soil. Studies have confirmed that lignite humic acid can retard the hydrolysis rate of urea and buffer soil pH, thereby changing the number and composition of microbial communities. In this case, the interference of urea application on the total amount and diversity of soil cells is buffered, the oxidation rate of ammonia to nitric acid and nitrite acid is slowed down, the nitrogen loss caused by denitrification conversion is also controlled, and the plant growth process is more fully supported by nitrogen, which is obviously more conducive to crop growth and yield increase. It is worth noting that the effects of different types of humic acid on soil microorganisms are also different, for example, humic acid and fulvic acid have obvious effects on the growth of nitrogen-fixing bacteria, which can enhance nitrogen fixation capacity, but the application effect of fulvic acid is more prominent, and the effect on the number of nitrogen-fixing bacteria is more significant than its effect on nitrogen fixation capacity.

http://www.jinfeng-biotech.com/