Humic acid is a class of organic matter created and accumulated by the remains of animals and plants, mainly the remains of plants, through the decomposition and transformation of microorganisms, as well as a series of processes in geochemistry. Its total is staggeringly large, trillions of tons. Rivers, lakes and seas, soil and coal mines, most of the surface has its traces. Due to its widespread presence, it also has a great impact on the earth, involving carbon cycles, mineral migration accumulation, soil fertility, ecological balance and so on. The soil contains the largest amount of humic acid, but on average less than one percent of it, and the total amount contained in brackish water is not small, but the concentration is lower.
Humic acid is a good biologically active. The organic carrier composed of a variety of functional groups is also an intermediate substance with plant respiration and photosynthetic metabolism functions, so it has great tolerance and can be combined with a variety of substances. Humic acid and pesticides are mainly combined through the interaction of ion bonds, hydrogen bonds, proton transfer, electron transfer, complexation, etc., and generate a new type of pesticide polymer complex, which is humic acid environmental protection pesticides. Research and practice have shown that humic acid can be compounded with insecticides, fungicides and herbicides, which can enhance the efficacy and reduce toxicity.
——Solubilization: Humic acid can play the role of surfactant, the surface tension of its metal salt is lower than the surface tension of water, which can produce obvious dispersion and emulsification effects on pesticides, and can improve the solubility of soluble pesticides;
——Synergistic effect: humic acid can enhance the absorption of pesticides by plants, can improve the biological activity of pesticides and plant growth regulators, and can significantly improve the effect of pesticides;
——Sustained release effect: humic acid has a significant inhibitory effect on the decomposition rate of pesticides, and the greater the amount of humic acid, the slower the speed;
——Detoxification effect: Humic acid can passivate the activity of those enzymes sensitive to pesticide toxicity in organisms, stimulate the activity of enzymes that have antagonistic effects on pesticides, and alleviate and reduce the toxicity in pesticides.
As a new type of fertilizer, organic and inorganic compound fertilizer is becoming the development direction of ecological agriculture fertilizer in the 21st century. Here, the application of humic acids in this fertilizer is mainly discussed.
A. The use of humic acid can change the physicochemical traits of too much salinity, too strong alkalinity, high dispersion of soil particles and poor soil structure in the soil, promote the formation of soil aggregates, make them into a good state, and thus create good conditions for plant root growth and development.
B. The application of humic acid can loosen the cultivated soil, destroy the accumulation of salt, reduce the salt content of the topsoil, play a salt barrier role, improve the emergence rate, reduce weak seedlings and dead seedlings, and make the plant grow healthily.
C. Humic acid has a high amount of cationic shift, which is more than 10 times higher than that of general soil. After application into the soil, the soil's ability to adsorb anions was significantly improved, and the surface salt content was reduced.
D. Saline-alkali land, especially alkaline soil, has a high PH value (9.0 or more), which directly endangers crop growth and even causes death, and the HIGH PH value also affects the effectiveness of phosphorus, iron, manganese, boron, zinc and other nutrients in the soil. The PH value of humic acid is 6.8 partial acidity, which can neutralize alkalinity, reduce the harm of alkalinity to soil and plants, improve low-yield saline land, and create good soil conditions for crop seedling growth.
1. Effect on soil microflora and enzyme activity
Soil microorganisms are one of the important reasons for soil composition, which have an important impact on the transformation of soil organic and inorganic matter, the circulation of nutrient elements, and the formation of an enzyme, an indispensable biologically active substance in the process of plant life activities. Humic acid can promote the activity of soil microorganisms, increase the number of soil microorganisms, enhance the activity of soil enzymes and other facts, has been confirmed by a large number of research data at home and abroad. Moreover, it was agreed that the application of humic acid increased the number of gas-prone bacteria, actinomycetes, and fibrolytic bacteria by more. It is beneficial to accelerate the mineralization of organic matter and promote the release of nutrients. Therefore, the application of humic acid can prevent and control root rot disease, yellow leaves, leaflets, and blight in fruit trees.
2. Humic acid has a synergistic effect on chemical fertilizers and micro-fertilizers
With the rapid development of China's chemical industry, the production and application of chemical fertilizers continue to increase, and increasing the application of chemical fertilizers has undoubtedly played an important role in the development of agricultural production, but with the increase of chemical fertilizer application, the cost of fertilizer has increased. Problems such as the reduction of fertilizer utilization rate are also gradually reflected. At present, China's nitrogen fertilizer interest rate is 30-50%, phosphate fertilizer utilization rate of 10-20%, potassium fertilizer utilization rate of 50-70%, how to improve the utilization rate of chemical fertilizer, has become a world attaches great importance to the research topic. There are many ways to improve the utilization rate of chemical fertilizers, and the most effective result at present is to use bioactive additives to activate humic acid, enhance its chemical synthesis, adsorption, chelation, microbial reproduction and other chemical activities and biological activities to effectively improve the utilization rate of chemical fertilizers.
3. The role of humic acid on crop growth and development
Humic acid contains a variety of functional groups, the activated humic acid becomes a highly efficient bioactive substance, the growth and development of crops and physiological metabolism in vivo has a stimulating effect, this property is not available in general fertilizers, activated humic acid efficient biological active substances according to a certain concentration of soaking seeds, soaking roots, dipping roots, spraying, watering, making bottom fertilizer, etc., have obvious stimulating effects on various crops. It is comprehensively manifested in the promotion of root development and the good influence on crop yield and quality factors.
A. Early germination, high emergence rate
The application of humic acid can accelerate seed germination and improve the emergence rate, which is especially significant in early spring and low temperature (generally can germinate 1 to 3 days earlier, and the emergence rate is increased by 10 to 30%).
B. The root system is developed and the absorption is strong
Humic acid has a special role in promoting the root development of crops, many agricultural scientists call humic acid as "root fertilizer", the impact on the root system is mainly manifested in, stimulating the division and growth of root-end meristem cells, so that seedlings root fast, secondary roots increase, root volume increases, root elongation, and ultimately lead to a great increase in the ability of crops to absorb water and nutrients.
C. Effect on the growth of aboveground part of the nutrient body
On the basis of adequate nutrient supply, the stimulating effect of humic acid can make the aboveground part of the plant grow vigorously. It is manifested in plant height, stem thickness, number of leaves, dry matter accumulation and other aspects.
D. Influence on yield and constituent factors
Humic acid has different yields and constituent factors for different crops. For grain crops, more ears, more grains, more grain weight, etc. play a role in increasing yield, and have good effects on tillering and reducing the empty grain rate in the early stage.
4. Effect on crop physiological metabolism and enzyme activity
After humic acid enters the plant body, it plays a stimulating effect on the plant, mainly manifested in the increase in respiratory intensity. The increase of photosynthesis and the enhancement of the activity of various enzymes allow the fruit to ripen in advance, and achieve high yield and high value (the marketability of cash crops).
5. Improve crop drought resistance
The application of humic acid can reduce the stomatal opening of plant leaves, reduce leaf transpiration, reduce water consumption, improve the water condition in the plant, and increase the moisture content of leaves. Thus laying the foundation for the division of the ears and in the seeds, the application of humic acid can also improve the content of chlorophyll and the normal progress of photosynthesis, which is very important for the accumulation of substances and the increase of 1,000 grain weight.
6. Enhance the cold resistance of crops
The application of humic acid has obvious effects on the early spring seedlings in the south and the cold resistance of wheat in the north. In the early rice seedlings in southern China, often encounter low temperature and rainy weather, often occur dead seedlings, rotten seedlings phenomenon, after the application of humic acid, the ground temperature has been improved, the quality of seedlings has generally improved. Southwest Agricultural University found in the experiment that winter wheat in most parts of northern China, due to the frequent occurrence of "cold spring," wheat seedlings are generally affected by winter damage, and the application of humic acid effectively improves the cold resistance of wheat and reduces frost damage to varying degrees.
7. Control of plant pests and diseases and immunity
Humic acid can effectively control underground pests and plant diseases and bacteria. According to a large number of research experiments in Beijing, Sichuan, Jiangxi proved that humic acid on fruit tree rot, leaflets, yellow leaf disease, cucumber downy mildew, pepper anthrax, viral disease, etc. have obvious control and bacteriostatic and sterilization effects, Shanxi Xindai Vegetable Research Institute two years of cucumber test showed that the application of humic acid, without the use of any pesticides, but cucumbers have not occurred major pests from beginning to end.
It has been more than 200 years since humic acid was first obtained from soil in 1786, and the first to pay attention to and study humic acid is the soil scientist. If we take the "Ujinsan" compiled in the works of Li Shizhen, a famous Chinese "medicine saint" in the Ming Dynasty, as an example, the application of humic acid has been more than 400 years, which fully explains the ancient history of humic acid.
At present, the state is determined to govern the ecological environment and improve people's production and lifestyle, which provides a big stage for the development and application of humic acid. Because humic acid has a special function, it will play its unique role in sand control, soil improvement, urban sewage treatment, ecological agriculture construction, production of green and organic products, development of drugs, health care products, etc.