The effect of humic acid on plant nutrition

(1) Effect of humic acid on nitrogen fertilizer

Humic acid has a synergistic effect on nitrogen fertilizer. Taking ammonium bicarbonate and urea as examples, the ammonium nitrogen in ammonium bicarbonate is unstable and highly volatile. After mixing with humic acid, humic acid contains functional groups such as carboxyl, phenolic carboxyl, and hydroxyl groups, and has a strong ion exchange effect. Capacity and adsorption capacity, can reduce the loss of ammonium nitrogen. Urea is an amide nitrogen fertilizer. After being applied to the soil, the nitrogen contained in it must first be decomposed and transformed by microorganisms before it can be absorbed and utilized by crops. If urea is applied to calcareous soil, the ammonium bicarbonate generated by the conversion of urea will react with alkali and volatilize rapidly, resulting in a decrease in the utilization rate of urea. Adding humic acid to urea has a significant synergistic effect on urea. Humic acid can complex and adsorb inorganic nitrogen compounds. Humic acid has strong cation exchange and adsorption capacity. The carboxyl group and phenolic hydroxyl group in its structure react with urea to form a humic acid-urea complex; The phenolic hydroxyl group and quinone group are similar in structure to the urease inhibitor hydroquinone, which can control the activity of soil urease and release urea slowly. Its manifestations are as follows: first, inhibit the activity of urease, slow down the decomposition of urea, and reduce volatilization loss; second, form complexes between humic acid and urea, gradually decompose and release nitrogen, and prolong the fertilizer efficiency of urea. At the same time, the bioactive substances in humic acid can promote the development of plant roots and nitrogen metabolism in the body, and promote the absorption of nitrogen.


(2) The effect of humic acid on phosphate fertilizer

Phosphorus is absorbed by crops, and its effective state is mainly hydrogen phosphate ion and dihydrogen phosphate ion. After calcium superphosphate, mono(di)ammonium phosphate, potassium dihydrogen phosphate and phosphorus in compound fertilizer are applied to the soil, soluble phosphorus is easily absorbed. Soil fixation, in acidic soil, it can be fixed into iron phosphate and aluminum phosphate by iron and aluminum ions; in calcareous soil, it can convert quick-acting phosphorus into slow-acting phosphorus. Therefore, the utilization rate of phosphorus fertilizer in the current season is only 10% to 20%. Humic acid has a large specific surface area, and its carboxyl, phenolic hydroxyl and other active functional groups compete with phosphate for the adsorption sites on the surface of the soil colloid, reducing or inhibiting the fixation of available phosphorus by the soil, and slowing down the conversion of available phosphorus to slow-acting phosphorus and ineffective phosphorus. The transformed and degraded nitrohumic acid can increase the moving distance of phosphorus in the soil, promote the absorption of phosphorus by plant roots, and improve the efficiency of phosphorus fertilizer. Humic acid not only has a synergistic effect on phosphorus fertilizers, but also has an effect on the potential phosphorus in the soil. Tests have shown that after applying humic acid to the soil, the content of available phosphorus in the soil increases significantly. At the same time, humic acid forms complexes with iron ions, magnesium ions, aluminum ions, and calcium ions in the soil to form humic acid metal phosphates, which inhibit the fixation of phosphorus and increase the availability of phosphorus.

(3) The effect of humic acid on potassium fertilizer

The principle of synergy between humic acid and potassium is reflected in the exchange with potassium ions, complexation reaction, and physical and chemical adsorption. The acidic functional groups (such as carboxyl, etc.) of humic acid can absorb and store potassium ions, which can not only effectively reduce the loss of potassium, but also inhibit the fixation of potassium by soil minerals. Humic acid combines with potassium to form a colloidal compound, which is not easily lost by leaching. The functional group contained in humic acid can replace and store potassium ions, which can not only prevent its loss in sandy soil or leaching soil, but also prevent clay from fixing potassium ions. Fulvic acid also has a certain dissolution effect on potassium-containing minerals, which can slowly release potassium and increase the content of available potassium in the soil.

(4) Effect of humic acid on trace element fertilizer

There are a lot of trace element reserves in the soil, but there are few active ingredients available for plants to absorb and utilize. Common micro-fertilizers in agricultural production are mainly calcium, magnesium, zinc, iron, copper, etc. After these micro-fertilizers are applied to the soil, they are easily converted into insoluble salts in the form of carbonates and sulfides, and their effectiveness is remarkable. fall. Humic acid can adsorb zinc ions, interact with iron ions, carry out quinone coordination with copper and manganese, and carry out carboxyl coordination with calcium and magnesium. The basic structural units are mostly composed of oxygen bridges (-O-), methylene The base bridge and other connections can undergo a chelation reaction with metal ions, making it a trace element in the chelation of water-soluble humic acid, which is beneficial to the absorption of plant roots and leaves, and improves the effective absorption and utilization of trace elements by plants.

The type of humic acid

(1) Soluble humic acid (soluble humic acid)

(2) Fulvic acid (fulvic acid)

(3) Brown humic acid (hymato melanic acid)

(4) Pyrotomalenic acid

(5) Active humic acid (active humic acid)

(6) Free humic acid (free humic acid)

(7) Water-soluble humic acid (water-soluble humic acid)

How to make the humic acid into granules?

The drum granualtor machine is much better to  make humic acid into granulation,which is convenient for transportation


Post time: Aug-18-2023
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