Humic Acid can Improve Saline-Alkali Land
Saline-alkali soil is a solid type widely distributed on the earth, which accounts for around 25% of the total land area. It contains soluble salts and the concentration of salt is high. Saline-alkali soil can directly inhibit or harm plants.
There are two ways to improve the saline-alkali soil: First, we can change the composition of soil colloidal adsorbent cations and improve the structure of the soil to prevent anti-alkalization. Second, we can adjust soil pH, improve soil nutrition and prevent the harm of soil salinization. Humic acid has achieved good results in improving saline-alkali soil in recent years.
Humic acid molecules contain a variety of functional groups, mainly oxygen-containing acidic functional groups, including aromatic and aliphatic carboxyl groups and phenolic hydroxyl groups. Since humic acid is weakly acidic, it has a large buffer range to H+ concentration. When improving alkaline soil, it neutralizes alkalinity and absorbs 20% of free Na+.
Humic acid is an organic colloid. Its internal cavities of different diameters can absorb some organic and inorganic substances. Humic acid can replace exchangeable Na+ in alkaline soil. For example: calcium humate is a kind of organic-inorganic colloid ameliorative substance, which can neutralize the alkalinity of soil, replace the sodium ion on the soil colloid, and eliminate the poison effect of soda.
In the meantime, humic acid can increase the content of soil organic matter and improve soil fertility. Generally speaking, the organic matter content of saline-alkali soil is less than 0.5%, and its bad physical and chemical properties will have adverse effects on agricultural production. The use of humic acid products can not only reduce the pH of saline-alkali soil but also greatly increase the content of organic matter, improving soil hardening and poor aeration characteristics. Last but not least, it can enhance the soil restoration ability.