Humic acid is diverse. Natural mineral humic acid is mainly organic matter formed by the decomposition and transformation of animal and plant remains, which is commonly found in soil, peat and weathered coal, and plays an important role in plant growth and soil ecosystem.
The main role of humic acid fertilizers is humic acid, followed by some nutrients such as large amounts, medium and small amounts, and microorganisms. The complex structure and characteristics of humic acid naturally determine that humic acid fertilizer is a multifunctional organic fertilizer. Among them, improving soil traits is one of the important roles of humic acid.
Improved acid soil and saline land
The pellet structure is the basis of soil fertility. The application of humic acid fertilizers in various places proves that humic acid fertilizers can increase soil aggregate structure. According to the test of Shenyang Institute of Ecological Application of Chinese Academy of Sciences, the soil water-stable aggregates of humic acid fertilizers increased by 10%-20%; for the application of bio-humic acid compound fertilizer, the soil water-stable aggregate structure also increased significantly. After the fertilizer is used, the soil is loose, the plants grow vigorously, and the soil resistance is enhanced.
Humic acid is an organic weak acid containing a variety of reactive groups. The weak acid (the weak base is also the same) and the weak acid salt have a buffering effect, that is, the pH of the solution is maintained to a certain extent. .
There are many acidic soils in southern China, mostly red and yellow mud fields. The pH value of this soil is 4.5-6, and some even reach 3.5. It is not suitable for crop growth, and the activity of microorganisms in soil is greatly reduced. After the application of the phosphate fertilizer, insoluble iron phosphate and aluminum phosphate are formed, which is also difficult to be absorbed and utilized by plants.
However, the application of humic acid fertilizers increases the humic acid in the soil, so that humic acid can interact with iron ions and aluminum ions in the soil to form a new compound, thereby reducing iron and aluminum ions to crops. The toxic effect, at the same time, can replace the hydroxide which is originally combined with iron and aluminum ions, neutralize the hydrogen ions, and reduce the fixation of phosphorus. In addition, the buffering effect of humic acid itself reduces the acidity of the acidic soil and is conducive to crop growth.
In terms of the transformation of saline-alkali land, the Shenyang Institute of Ecological Application of the Chinese Academy of Sciences has carried out research on the transformation of saline-alkali soil by humic acid fertilizers for many years, and has achieved gratifying results. Practice has proved that the application of humic acid fertilizers can significantly modify the saline-alkali land. Firstly, it can change the structure of the soil surface layer of saline-alkali soil, increase the structure of aggregates, destroy the rising conditions of salt, play a role of "separating salt" and reduce the accumulation of salt in the surface layer of soil. In addition, humic acid fertilizers can adsorb and retain a large amount of harmful ions from the soluble salts of the soil, and reduce the salt concentration in the soil solution, so that the salt concentration in the aqueous solution contacted when the seeds are rooted becomes smaller, and the concentration is reduced. The harm of salt to seeds. For example, Dongying City, Shandong Province, applied humic acid fertilizer on heavy alkali land, and the seedling rate increased from 20% to 30% to 90%, and grain production increased by 53.5%.
Promote soil microbial system balance
Humic acid fertilizers not only provide microbial nutrients, but also create good soil environmental conditions for microbial activity. There are many microbes in the soil that are invisible to the naked eye. The number of microbes per gram of soil is tens of millions, hundreds of millions or even billions. Their effects on soil ecosystems are evident.
It has been determined that after the application of humic acid fertilizers, the number of microorganisms decomposing cellulose is doubled, the ammoniated bacteria that decompose amino acids release nitrogen are increased by about 1 to 2 times, and the soil autobiotic ammonia bacteria is more than doubled. This will accelerate the decomposition of organic matter in the soil, increase the amount of soil humus, release and accumulation of available nutrients, and facilitate crop absorption and utilization.
Since the humic acid fertilizer is black, the application of the soil deepens the color of the soil, increases the absorption of sunlight by the soil, and the humic acid promotes the microbial decomposition of the soil and generates heat, so it can raise the ground temperature and enhance the cold and frost resistance of the crop. ability. According to local experimental observations, the application of humic acid fertilizer can increase the ground temperature by 1 to 3 degrees Celsius.
In short, humic acid fertilizers are an important development direction in the development of fertilizers.