Van Xuong fish. You probably never thought that an animal could live without a head, heart and bones. In fact, this species existed 500 million years ago and exists until today, in addition, they are also considered “cousins” of the ancestors of many vertebrates today. The family of vertebrates is extremely prosperous today, with more than 60,000 members, all of whom have different looks, habits and temperaments, but this “cousin” only has one child left. the only living species, they are named Amphioxus – Van Xuong fish, this species is also considered a living fossil. Although Van Xuong fish is called a fish and at first glance, it is very similar to a fish, but it is not actually a fish. On our planet today, most of the animals that exist are vertebrates, such as horses, cattle, sheep, chickens, ducks, dogs, cats, tigers, turtles.. Of course, there are us humans as well. What makes this particular “fish” so strange and unlike any other is that they are cephalopods, without a backbone, but still grouped with vertebrates, Chordates live and form the phylum Chordate. Biologists think that Van Xuong fish are animals in the transitional evolutionary stage from invertebrates to vertebrates, today they are considered to be ancestors of fish, but they are completely different. not fish. The skin of Van Xuong fish consists of two main layers: the epidermis (epidermis) on the outside and the dermis (dermis) on the inside. Unlike most vertebrates, their epidermis has only one layer of cells, while the dermis is underdeveloped, mainly composed of glue or elastic connective tissue. There are more than 66,000 animals in the order Phylum Chordata. The most special thing is that vertebrates account for the largest proportion, with more than 66,000 species, the main subphylum is the sea squid, and there are currently about 3,000 known species; and cephalopods, there are only two families of Van Xuong and Asymmetron fish – there are 30 species. In fact, the skeleton of this fish is the rope that runs along the body and back from the tail to the head. In the gill slit region, the skeleton is a network of many horizontal and vertical connecting rods. The fins and tentacles are also supported by the connecting rod. Their central nervous system is a neural tube running along the body, located above the spinal cord but not reaching the end of the spinal cord, wrapped in a protective glue membrane. Although Van Xuong fish looks like a fish, the biggest difference between it and vertebrates is that it does not have a real head, sense organs such as smell, sight and hearing, even a skull or a skull. teeth are also something too fictitious for them. This animal only has a tuft of elastic “legs” on the head that acts as support for the body. The most amazing thing is that it doesn’t even have a heart, instead it relies on the beating of a portion of blood vessels to transport blood. Their musculature is less differentiated and typically segmented. Therefore, the muscles can only guarantee simple bending movements, suitable for the lifestyle buried in the sand. The muscular system consists of many muscle segments (myomera), arranged from the anterior end to the posterior end of the body. The muscle segments are separated by septa of connective tissue (myosepta). The muscle segments on both sides of the body are arranged alternately with comb teeth. As a result, when swimming, the body bends in the horizontal plane. Amphioxus is widely distributed in the shallow waters of the ocean, Qingdao and Xiamen in China are their main habitats. In addition, there are the coasts of Southeast Asia and the coasts of California and Florida, Norway, the Mediterranean and Africa. Due to its rich nutrition and delicious taste, Van Xuong fish is considered a traditional delicacy in Southeast Asia. Van Xuong fish is 3 to 5cm long, very strange shape. The long, flattened body looks almost like a pole. The whole body is pinkish-pink, semi-transparent, the muscle fibers are clearly visible. They have no scales, no fins, no spine, their internal organs are just a rhythmically pulsating complex tube. There are no senses like eyes, nose, ears. There is no decomposition for the gastrointestinal tract. Apart from the mouth and pharynx, the only remaining part of the intestine is the intestine leading to the anus. Van Xuong fish often follow the tide to swim into the estuary where the seabed is shallow, almost defenseless but capable of penetrating the ground. Their lifespan is about 3-4 years, they often bury half of themselves in the sand, while the other half is exposed to receive plankton from the river. Their musculature is less differentiated, so they can only move in the water by simple bending movements. When not moving, they often bury themselves in the sand. The respiration of Van Xuong fish is also similar to other fishes. They vibrate the cilia (the tentacles in the mouth) to bring water from them to the gill slit. The wall of the gill slit has many blood vessels, where gas exchange occurs.

In the winter-spring crop 2020-2021, Quang Tri Agricultural Extension Center has implemented an organic rice production model using Guilin organic fertilizer at An Long Cooperative, Trieu Hoa commune, Trieu Phong district to change awareness and transfer of technical processes and organic farming methods to people. From being dependent on chemical fertilizers, people have realized great benefits from applying organic fertilizers. Photo: PVT. The model is implemented on a scale of 10 hectares, 50 participating households. After selecting the demonstration site, the Quang Tri Agricultural Extension Center organized a training session to guide the process of organic rice intensification, especially organic composting. The implementation of organic composting was carried out early (since November 2020). At the same time, the technical staff has coordinated with the Commune People’s Committee and the Management Board of the cooperative to closely manage and supervise the implementation of the model as required by the program. Rice production process using sowing tools, HC95 rice variety has high quality, high yield and good quality. Master Tran Thi Thuy, the technical officer directing the model, said that in the process of planting, households have been instructed to carefully prepare the soil, create a flat surface, and drain water before sowing. Make sure to soak the seeds in the correct technique, regularly check the sprouts, when the sprout is 1/3 of a rice grain (cracked pineapple spikes), the roots are ½ of a rice grain, sow. Healthy, disease-free, productive, high-quality rice fields thanks to organic production. Photo: PVT. Rice is sown by row sowing tool, the amount of seed sown for 1 sao (500 m2) is 3.5 kg. Use composted organic fertilizer for lining and Guilin organic fertilizer during the growth and development of rice plants. Rice does not use chemical fertilizers, chemical pesticides, only biological pesticides are used when pests and diseases occur. Scientific irrigation water regime, suitable for the growing needs of rice plants. Fertilizers are applied in 4 main growth and development periods of rice… Calculating for 1 hectare, the amount of fertilizer for each application is as follows: Apply the last fertilizer before harrowing with 6-7 tons of broken organic fertilizer, 500 kg Guilin microbial organic fertilizer, 300 kg Guilin mineral fertilizer ; first application at rice 20 days after sowing with the amount of Guilin mineral fertilizer: 500 kg; second fertilizer at rice 32-35 days after sowing with 400 kg Guilin mineral fertilizer; 3rd application at rice 62 days after sowing, combined with spraying foliar fertilizer with 300 kg of Guilin mineral fertilizer, 40 packs of Guilin foliar fertilizer. Mr. Doan Tho Hoa, An Long village (Trieu Hoa commune, Trieu Phong commune) participates in the model of organic rice production with an area of ​​4 sao. Meeting with us, Mr. Hoa could not hide his joy and said: The difference of the organic rice production model is the use of Guilin organic fertilizer and the use of manure composted with Trichoderma products. The environment in the fields of Trieu Hoa commune (Trieu Phong, Quang Tri) is greener, cleaner and more beautiful thanks to organic rice farming. Photo: PVT. Compared to HC95 rice, which farmers cultivate in the usual way, the model rice plants are organically healthy, have durable green leaves, moderate green color from the beginning to the end of the crop, and the rice plants are free from pests and diseases from the root At the top, the color of the yellow rice grain is brighter. “During the last storm of the season with strong gusts of wind, conventional farming fields all fell, especially the model fields have strong roots, so they do not fall, which is very convenient for farming. harvest”, Mr. Hoa assessed. Mr. Doan Duc Tam, another household participating in the model, said that when cultivating rice in the organic direction, it will greatly limit the situation where pesticide bottles are thrown away in the field, but instead, the awareness The people’s compliance with the process of caring for rice with organic fertilizers has been increased. “During the implementation of the model, from planting, tending to harvesting, my relatives and I always feel secure, without fear of toxicity when taking care of rice,” said Mr. Tam. Multi-faceted benefits In the process of rice production, if using inorganic fertilizers for many years, without adding organic fertilizers as well as overusing inorganic fertilizers, it will cause harm such as increasing the susceptibility of plants to diseases. , kill beneficial microorganisms, make many arable land areas lose fertility, imbalance of nutrients in the soil, hard soil, decrease crop yield and increase production costs. impact on the environment and human health… Not using chemical pesticides, focusing on integrated pest management in the field has shown farmers countless benefits. Photo: PVT. The application of organic production processes increases the fertility of the soil, increases the minerals and effective microorganisms for the soil, has a very good effect on soil improvement, especially for the soils that have been and are being developed. degraded. In the long run, it will help the rice plant’s better resistance to pests and diseases. During the flowering period, the field will be less infected with planthoppers, dry, give long cotton, rice is free of pests, rice is clear, rice is soft and has a characteristic aroma. Economically, the yield is estimated at 57 quintals/ha for the HC95 variety, with the selling price of 9,000 VND/kg, giving a profit of 25 – 27 million VND/ha, 10-15% higher than the mass market. In addition, reducing the amount of sowing seeds by using a sowing tool, making rice plants grow healthy and balanced, this is an important factor contributing to improving productivity and economic efficiency. In terms of environment, ecology, using Guilin microbial and mineral organic fertilizers, combined with manure, stubble decomposition products, creating a favorable environment for beneficial microorganisms, improved soil. Better yet, the rice plants grow in balance, the environment is safe, the field ecosystem is secure, there are fish, snails, and crabs… living in the rice fields. Organically produced rice not only ensures quality and productivity, but also significantly reduces production costs. Photo: PVT. Developing agriculture according to organic farming methods not only contributes to the creation of organic products that are beneficial to human health, but also raises awareness and changes farming methods in rice production towards organic sustainable, ensuring safe products, the country’s environment is not polluted, contributing to the protection of the environment and field ecosystems. According to Mr. Phan Ba ​​Dinh, Chairman of the People’s Committee of Trieu Hoa Commune, Trieu Phong District: Local households have also felt the risk of abusing inorganic fertilizers, abusing chemical pesticides, affecting quality. agricultural products, environment and public health, so the model implementation is highly accepted by households. Mr. Dinh has learned from experience: If the technical process in the model is followed, such as using microbial organic fertilizers and Guilin mineral fertilizers, combined with manure, Trichoderma; If the amount of water is guaranteed, the weather is favorable, it is necessary to go through many production crops, the fields are improved, the fertility of the soil is improved… “From the initial support of the Provincial Agricultural Extension Center, it has helped households to firmly grasp and understand the technical stages of organic production that are different from mass production. In the next seasons, we will direct, and have supportive policies, and at the same time continue to propagate and replicate the model, encouraging farmers to implement this superior farming model,” Dinh said. know.