Humic substances in agricultural applications [Date: 2005-4-25] Source: Author: Wenjun [font: medium and small] China Humic Acid Industry Association senior Wenjun organic and inorganic fertilizer as a new fertilizer, is becoming Development Direction of Fertilizer for Ecological Agriculture in the 21st Century . Here mainly discusses the application of humic acid in the fertilizer in agriculture. 1. Humic acid can improve soil (1) Improvement of saline-alkaline soil A. Promote the formation of soil aggregates: Soil agglomerates are the basic units of soil structure. The use of humic acid can change the physicochemical properties of the soil, such as high salt content, high alkalinity, high dispersion of soil particles, poor soil structure, promote the formation of soil aggregates, and make it into a good state, thereby creating the growth and development of plant roots. good conditions. (Xinjiang Institute of Biology, Soil and Desert Research) B. Reducing the amount of salt in the topsoil: Applying humic acid can loosen the soil in the cultivated layer, destroy the accumulation of salt, reduce the salt content in the topsoil, and play a role in separating the salt, increasing the emergence rate, reducing weak seedlings and dead seedlings, and making the plant grow healthily. (Information of Zhangbei Soil Fertilizer Station in Hebei Province) C. Increase soil exchange capacity: humic acid has a higher amount of cation conversion, more than 10 times higher than normal soil. When applied to the soil, the adsorption capacity of the soil to the anions is significantly increased, and the surface salt content is reduced. (Xinjiang Institute of Biology, Soil and Desert Research) D. Reducing the pH of saline-alkaline soil (PH value): Saline-alkaline soils, especially alkaline-earth soils with high pH (above 9.0), directly harm crop growth and even cause death. In addition, excessive PH value also affects phosphorus, iron, and manganese in soil. The effectiveness of nutritive elements such as boron, zinc, etc. The pH value of humic acid is 6.8, which can neutralize the alkalinity, reduce the damage of alkalinity to soil and plants, improve the low salinity production, and create good soil conditions for the growth of crop seedlings. (2) Improvement of white and red soils A. Albic soil is mainly distributed in the northeast region of China. The cultivating layer bottom of this type of soil is about 5~10cm ash layer. This layer has poor soil water, large cohesive acidity, poor soil structure, weak biological activity, and the roots of the crop are difficult to find. Penetration, which is the main reason for low yield. After the application of humic acid, the soil capacity decreases significantly, and the total porosity and water holding capacity increase accordingly. This helps to increase the ability of the soil to retain water and fertility, thereby improving the growth environment of the crop and reducing the mechanical energy consumption during ploughing. Cost creates conditions. (Information of Jilin City Agricultural Institute) B. The improvement of red soil This type of soil is distributed in the red soils of the southern provinces, tropical and subtropical regions of China. Because of the high temperature and rain in the south, the organic matter in the soil decomposes quickly, and the fertilizers are easily lost with rainwater. As a result, the organic matter in the soil is poor. Due to the large amount of rain, most of the alkaline components in the soil are leached, and acidic substances such as iron and aluminum that are not easily lost are relatively accumulated. As a result, red soil is acidic or strongly acidic, and the soil structure is destroyed, especially when the soil becomes dry. "Acid, mash, board, dry." (Data from the Farming Institute of Jiangxi Academy of Agricultural Sciences) After application of humic acid, physical properties of red soil can be improved, soil aggregates are increased, soil capacity is decreased, pores are increased, water retention is high, and application of humic acid can also improve red soil chemical properties. Mainly in the increase of soil organic matter content, available nutrient content increased, the mediation of acidity and alkalinity moderate, suitable for plant growth. (3) Effects on soil microbial flora and enzyme activity Soil microorganisms are one of the important reasons for the composition of soil components, the conversion of soil organic matter, the recycling of nutrient elements, and the indispensable organisms in the process of plant life activities. The formation of the active substance, the enzyme, has an important influence. The fact that humic acid can promote the activities of soil microorganisms, increase the amount of soil microorganisms, and increase the activity of soil enzymes has been confirmed by a large amount of research data at home and abroad, and it is agreed that the application of humic acid makes aerobic bacteria, actinomycetes, and fibers The number of decomposing bacteria increased 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 rot disease, yellow leaves, leaflets and blight of fruit trees. 2. Humic acid has a synergistic effect on chemical fertilizers and micronutrients. With the rapid development of China's chemical industry, the production and application of chemical fertilizers are increasing, and the addition of chemical fertilizers has undoubtedly played an important role in the development of agricultural production, but with the application of chemical fertilizers. The increase in the use of fertilizers, the increase in investment costs, and the reduction in the use of chemical fertilizers have also been gradually reflected. At present, China's nitrogen fertilizer rate is 30 to 50%, and the utilization rate of phosphate fertilizer is 10 to 20%. The utilization rate of potash fertilizer is 50 to 70%. How to increase the utilization rate of chemical fertilizer has become a research topic that the world has attached great importance to. There are many ways to increase the utilization of chemical fertilizers. At present, the most effective result is the use of biologically active additives to activate humic acid, enhance its chemical activity and biological activity such as chemical combination, adsorption, chelation, and microbial reproduction to effectively increase the utilization of chemical fertilizers. (1) Synergistic effect on nitrogen fertilizer A. Reducing Nitrogen Volatilization Losses Nitrogen fertilizers, represented by urea and carbon amines, are highly volatile and generally have a low utilization rate. Farmers generally believe that they are “stormy, swift, and short,†but can increase absorption when mixed with humic acid. The utilization rate is 20 to 40% (the time that the nitrogen released by the carbon amine is absorbed by the crop for more than 20 days, but can be more than 60 days after being mixed with humic acid), and the farmers think it is “slow, stable and longâ€. B. The effect of humic acid on soil available nitrogen The effect of humic acid on potential nitrogen in soil is various. The humic acid stimulation increases the soil microbial prevalence, resulting in faster organic nitrogen mineralization and higher humic acid content. The exchange amount of salt can reduce the loss of nitrogen volatilization, and also increase the content of soil available nitrogen. (2) Synergism of Phosphorus Fertilizers The effect of humic acid on phosphate fertilizers has been studied abroad for many years. China has also carried out research in this area. The results show that without adding humic acid, phosphorus moves vertically in the soil from 3 to 4 cm. The addition of humic acid can be increased to 6-8 cm, which is nearly double the amount of humic acid. It is helpful for crop root absorption (Shenyang Agricultural University). Humic acid has a significant effect on the decomposition of phosphate rock, and it has a protective effect on available phosphorus and reduces the effect of soil on rapid Phosphorus fixation and promotion of phosphorus uptake in the roots of crops, and increase the use of phosphate fertilizer absorption rate have a very high value. (3) Potentiating effect on potash fertilizer The synergistic effect of humic acid on potash fertilizer is mainly manifested in that the acidic functional group of humic acid can absorb and store potassium ions and prevent loss of water in sandy soil and soil with strong leachability. To prevent the sticky soil from fixing potassium, it may have dissolution effect on potassium-containing silicates, potassium feldspar and other minerals, and can slowly decompose and increase the release, thereby increasing the content of soil available potassium. (4) Synergies for Micronutrients For crop growth, in addition to the three major elements of nitrogen, phosphorus, and potassium, calcium, magnesium, boron, manganese, copper, zinc, molybdenum, and other intermediate and trace elements are needed. The composition of various enzymes in crops has a very important influence on promoting the growth and development of crops, increasing disease resistance, increasing yield, and improving quality. Sometimes it is not the lack of trace elements in the soil, but the amount of effective components that can be absorbed by the plants is too little. The application of humic acid can generate chelation reaction with insoluble trace elements, and produce chelate trace elements of humic acid with good solubility and can be absorbed by crops, which is favorable for root or leaf surface absorption, and can promote the absorption of trace elements from The transfer of roots to the ground, which is the role of inorganic trace element fertilizers does not have. 3. The effect of humic acid on the growth and development of crops Humic acid contains a variety of functional groups, and activated humic acid becomes a highly efficient biological active substance, which has a stimulating effect on crop growth and physiological metabolism in vivo. This characteristic is not available in general fertilizers. The activated humic acid high-efficiency biological active material adopts such methods as soaking, immersing roots, smashing roots, spraying wine, watering, and making base fertilizer at certain concentrations, and has obvious stimulating effects on various crops. Comprehensive performance in promoting the development of the root system, a good impact on crop yield, quality factors. (1) Impact on crop development A. Early germination, high rate of emergence of humic acid application, can accelerate seed germination, improve the emergence rate, especially in early spring, low temperature (usually 1 to 3 days earlier to germinate, emergence rate increased by 10 to 30%). B. Strong root systems and strong humic acid absorption have a special role in promoting the development of root systems in crops. Many agricultural science personnel refer to humic acid as a "root fertilizer", and its effects on root systems mainly manifest in stimulating cell division in root meristems. The growth will make the seedlings grow faster, the secondary roots will increase, the root volume will increase, and the roots will elongate. This will ultimately lead to a great increase in the ability of crops to absorb water and nutrients. C. Effects on the growth of part of the trophozoites On the basis of adequate supply of nutrients, the humic acid stimulated the vegetative growth of the aboveground part of the plant, showing in the aspects of plant height, stem diameter, number of leaves, and dry matter accumulation. D. Effects on yield and compositional factors Humic acid has different yields and compositional factors for different crops. It has the effect of increasing grain yields for many food crops, spikes, grains, and grains, etc. It has good effects on tillering and reduction of emptying rate in the early period. effect. (2) Effects on crop physiology, metabolism and enzyme activity After humic acid enters the plant, it stimulates the plants, mainly in terms of increased respiratory intensity, increased photosynthesis, and increased activity of various enzymes, thereby making the fruit Coloring and maturing in advance, achieving high yields and high values ​​(marketability of cash crops). (3) Mechanism of stimulating the crop humic acid is activated as a highly efficient bioactive substance. After being absorbed by the plant roots and leaves, humic acid can promote the absorption of inorganic nutrients and increase the absorption of water. In particular, the respiration of plants is outstanding, and the literature referred to it as "breathing fertilizer." In the absence of oxygen is even more prominent, how to use the humic acid stimulation has always been a concern. Using humic acid to promote germination, increase seedling rate, obtain the effect of Miaoqi, Miaoquan and Miaozhuang. Using humic acid solution to dip root and dip root has become an agricultural technology measure to improve survival rate by rod insertion or transplanting. . (4) Improving crop drought resistance The application of humic acid can reduce the stomatal opening of the leaves, reduce the transpiration of the leaves, reduce the water consumption, improve the water condition of the plants, and increase the moisture content of the leaves, thus allowing for the growth of the leaves and seeds. The foundation is laid, the application of humic acid can also increase the content of chlorophyll and normal photosynthesis, and it is very important for the accumulation of substances and the increase of 1000-grain weight. (5) Enhancing the cold resistance of crops The application of humic acid has significant effects on early spring sowing in the south and cold resistance of northern wheat. During the early rice growing seasons in southern China, we often encounter low temperature and rainy weather. Dead seedlings and rotten seedlings often occur. After humic acid is applied, the ground temperature is improved and the seedling quality is generally improved. During the experiment, Southwest Agricultural University discovered that winter wheat in most parts of northern China often suffers from winter damage due to frequent “cold springsâ€. Applying humic acid effectively improves the cold-resistance of wheat and mitigates freezing injury to varying degrees. (6) Prevention and control of plant diseases, insect pests and immunity Humic acid can effectively control underground diseases and pests, and plant diseases and germs. According to a large number of research experiments in Beijing, Sichuan, and Jiangxi, humic acid has shown obvious control and bacteriostatic effect on rot of fruit trees, leaflets, yellow leaf disease, downy mildew of cucumber, anthracnose of pepper, and viral diseases. The two-year cucumber test conducted by the Institute of Newgrass Vegetable Research shows that humic acid is used without any pesticides, but no major pests and diseases have occurred in cucumbers from beginning to end. 4. Effect of humic acid on changing the quality of agricultural products With the improvement of human living standards, it is required not only that crops have higher yields, but also that they have good quality characteristics. The quality of agricultural products is affected by many factors. The most important factor is that fertilizers, scientific research personnel and the vast number of farmers have concluded that in a long-term practice, an experience of applying humic acid not only has obvious effect of increasing production and economic benefits, but also humic acid is A pollution-free organic fertilizer can improve the quality of agricultural products and is an important product of the green basic industry. (1) Impact on the quality of food crops A. Rice. According to the statistical data of Yunnan Research Institute of Fung Fertilizer, it is shown that the application of humic acid organic fertilizer in rice is 25-33% higher than that of inorganic fertilizer, crude protein content is increased by 6.6%, and starch content is increased by 10.5%. B. wheat. According to demonstrations of humic acid and organic fertilizer in Beijing, Henan, and Gansu, the result is an increase of 6.8-12% in wheat yield. It has less investment, quick effect, long fertilizer effect (fertilizer efficiency is more than one year), and has significant economic benefits. The Agricultural Bureau of the Ministry of Agriculture, Animal Husbandry and Fisheries held a conference in Henan for the participation of agricultural administrative departments from 11 provinces and municipalities in northern China. The results of this research have drawn great attention from the international plant physiology community. The results of the large-scale wheat experiment conducted by the Institute of Biology, Henan Academy of Sciences show that the increase rate is more than 11%, and the input-output ratio is 1:40. The effect is excellent, so it is suitable for popularization and promotion. C. corn. According to the statistics of the Agriculture Bureau of Gongzhuling City, Jilin Province, corn humic acid is used to promote early maturing. Large-scale demonstration results show that the average yield increases by 7-9% compared with other fertilizers, and 25-40 kg of corn per mu. In 1981, the Bureau of Land Use of the Ministry of Agriculture organized the three northeastern provinces and the agricultural administrative department to hold an on-site meeting to promote. (2) Effect of using vegetable quality According to Shanxi Agricultural University's Northwest Agricultural University test results, the application of humic acid than other fertilizers, the potato starch content increased by more than 10%, the increase rate of 12-19%, tomato increased vitamin 654.8%, the rate of increase was 20-35%, and easy to store for a long time, no chemical fertilizer damage (excluding harmful ingredients). (3) Test results of fruits and vegetables A. The effect of sugar content in cantaloupe: humic acid is applied, and the sugar content of cantaloupe is 8-15% higher than that of non-application. (Institute of Soil and Fertilizer, Xinjiang Academy of Agricultural Sciences) B. Effect on sugar content and vitamin C content of watermelon: After applying humic acid to watermelon, the sugar content increased by 13-31.3%, and the content of vitamin C increased by 32-4.6% (Southwest Agricultural University). In soils with poor fertility, the application of phytic acid to organic fertilizers increased the relative sugar content by 16-31% and the vitamin C increased by 13.4-63.6%. (Jiangxi Academy of Agricultural Sciences)