Those are preparations containing microorganisms. Include groups of useful microorganisms such as bacteria, fungi, actinomycetes used to make fertilizers. Among them are important groups of microorganisms that fix nitrogen, dissolve phosphorus, decompose organic matter, stimulate plant growth, etc.
Read more : >> Application of Streptomyces sp in agriculture
To process microbiological fertilizer, microorganisms are cultured and multiplied in the laboratory. When the concentration of microbial cells is quite high, people mix with additives and then dry them in bags.
In recent years, in many countries around the world, people have organized industrial production of some types of microorganisms and sold them on the domestic market. Some types of microbial fertilizers are widely sold in the world market. However, the types of microorganisms are very small and only a small part compared to the chemical fertilizers on the fertilizer market.
Nitrogen fixing nitrogen fertilizer. There are many species of microorganisms that are able to fix N from the air. Noticeable species include: blue-green algae (Cyanobacterium), Azotobacter, Bradyrhizobium, Rhyzobium; actinomycetes Actinomyces, Klebsiella.
Most nitrogen-fixing bacteria usually live in symbiosis with legumes. They invade the roots and live in symbiosis in them, forming nodules in the roots. They use plant organic matter to grow and absorb nitrogen from the air to feed the plant, a part that accumulates in their bodies.
Blue-green algae symbiosis with strawberry hyacinth and accumulate nitrogen accumulation makes strawberry hyacinth high in protein, becoming a valuable green manure crop.
Recently, along with the advances of science and technology, scientists have used gene technology to create nitrogen-fixing microorganisms with many good features: high nitrogen fixation capacity. , good symbiotic ability. Biotechnology also helps create strains of microorganisms that are highly competitive with soil microorganisms. On the other hand, biotechnology has allowed scientists to isolate genes that regulate nitrogen fixation from bacteria and transplant them into the nucleus of a plant's cell, making some species of plants also have the ability to nitrogen fixation like bacteria.
Currently on our country's fertilizer market, nitrogen fixing microorganisms are sold under the following trade names:
– Nitragin fertilizer contains nodule bacteria of soybean.
– Rhidafo fertilizer contains peanut nodule bacteria.
– Azotobacterin contains free protein-sucking bacteria.
– Azozin contains bacteria that absorb protein from the air living in the rice field. This fertilizer can be mixed with rice seeds.
Phosphorus soluble microorganisms. Plants can only absorb phosphorus from soil in soluble form. Therefore, plants can only absorb phosphorus in the form of easily digested in the soil. Phosphorus in soil is difficult to dissolve in soil. Therefore, there are many types of soil such as basalt, black soil, etc., the amount of phosphorus in the soil is quite high, but the plant cannot absorb because phosphorus is in a form that is difficult to dissolve.
In soil, there usually exists a group of microorganisms capable of dissolving phosphorus. This group of microorganisms was named HTL (dissolved phosphate, English-speaking countries named this group as PSM – phosphate solubilizing microorganisms).
Phosphate dissolution group includes: Aspergillus niger, some species of genera Pseudomonas, Bacillus, Micrococens. This group of microorganisms is easy to grow on artificial media. In many places, people have mixed biomass or spores of phosphate-soluble microorganisms after culturing and multiplying in the laboratory, with phosphorite or apatite powder and then applied to the plants. The use of HTL microbial inoculants is highly effective in areas where the plants lack phosphorus.
Some microorganisms that live in symbiosis on the roots are able to absorb phosphorus to supply the plants. Of these, significant species is VA mycorrhiza. This species can dissolve iron phosphate in soil to provide phosphorus to plants. In addition, this species also has the ability to mobilize the elements Cu, Zn, Fe … for plants. Many places where people use VA mycorrhiza has increased the yield of oranges, lemons, apples, coffee … Cultivating VA mycorrhiza on artificial media is very difficult. So currently the products containing VA mycorrhiza are only sold very limited in the US fertilizer market.
In recent years, in the fertilizer market in some countries, they have sold phosphorus – bacterin inoculants containing phosphorus-releasing bacteria from organic substances.
Microorganisms stimulate tree growth. Including a group of different species of microorganisms, including bacteria, fungi, actinomycetes, etc. This group was isolated by soil microorganism groups.
People use preparations of selected microbial groups to spray on the tree or apply to the soil to make the plant grow and develop well, less pests, increase productivity. This product also increases the germination capacity of seeds, increases seed weight, promotes strong root development. Thus, this preparation has a relatively general effect on the crop.
To produce microbial inoculants that stimulate plant growth, microbiological fermentation technology is used. In developed countries people use automatic fermentation equipment, large capacity. In our country, the technology used to ferment on semi-solid medium to produce this product, initially has good results.
In recent years, our country has been conducting the testing of EM preparations of Japanese professor Teruo Higa. This product was named Effective microorganisms (EM). This is a mixture of a group of useful microorganisms including acid lactic bacteria, some yeasts, some actinomycetes bacteria, photosynthesis bacteria, etc. At the meeting to evaluate the results of using EM in In Thailand in November 1989, the scientists assessed the good effects of EM as follows:
– Improving physicochemical properties and biological properties of soil.
– Reduce the germs of pests and diseases in the soil.
– Increase the efficiency of organic fertilizers.
– Plants grow and develop well, giving high yields and good agricultural quality.
– Limit pests and diseases of plants.
– Contribute to cleaning the environment.
EM preparations are also used in animal husbandry. Feeding cattle, EM increases the microbiota in the intestinal tract, increases health, reduces odor of feces.
EM is also used to clean aquatic environment.
Some points to pay attention to when using microorganisms:
Fertilizers produced in our country often have a brown, black powder, because most of the production places use peat as fillers and bacterial carriers.
Domestic fertilizer is often used by mixing with watered seeds to moisten seeds before sowing for 10 – 20 minutes. The concentration used is 100 kg of seeds mixed with 1 kg of microorganisms.
Domestic microbial preparations are usually not stored for long. Usually, after 1 to 6 months, the activity of the microorganisms in the preparation sharply decreases. Therefore, when using should carefully review the date of manufacture and the use time indicated on the packaging.
Microorganism inoculants are a living material, so if stored at temperatures higher than 30oC or in direct sunlight, some microorganisms die. Therefore the effectiveness of inoculants is reduced. The compost should be stored in a cool place and not exposed to sunlight.
Microbiological fertilizers usually only work in the right soil and climatic conditions. Usually they thrive well on high bare feet, for upland crops.
Note : The post was posted on Giatieu.com Since 2012 there should be issues that are no longer relevant. Community reference to contribute to improving the understanding of the types of microorganisms.
Follow Department of Horticulture
