Onion is a common vegetable, which is also called onion. It has the medicinal value of preventing cardiovascular and cerebrovascular diseases and lowering blood pressure and anti-cancer. Onion is resistant to storage and transportation. It is grown in all parts of the country from north to south. In some areas, onion cultivation has become a leading agricultural industry. Here are some of the high-quality and high-quality cultivation techniques for onions. First, the onion cycle Onions are annual vegetables, and the life cycle is slightly different due to different cultivation methods. The whole life cycle has several stages. Germination period It takes about 15 days from seed germination to the first true leaf. According to the hard characteristics of onion seed skin, the sowing should not be too deep. The sowing depth is about 0.3 cm. After covering the soil, sprinkle with grass ash to keep the ground loose. The soil should not be too thick, and the soil should be kept moist before the seedlings are unearthed to prevent soil compaction on the soil surface and affect the emergence rate. There are many vegetable farmers who will appear in the process of nursery, and the emergence rate is not the whole phenomenon. That is, after we planted, the soil is not evenly distributed after the soil is thinned. The germination rate of the seeds is “clear and cloudy†and the other areas are not out. One is that the soil is too thick, and the other is caused by drought and water shortage in the soil. 2. Seedling stage From the first true leaf to the colonization, most vegetable farmers use autumn seedlings and plant seedlings before winter. Before the onion is transplanted, it usually takes about 50 seedlings to pass through the wintering period of 120---150 days. If the overwintering seedlings are too large, it is prone to bolting in spring. Special attention must be paid to the wintering seedlings to maintain 3-4 true leaves, the stem diameter is about 0.6 cm, the seedling height is about 20 cm, the bolting rate is low, and the yield is high. During the cultivation process, attention should be paid to the prevention of cold and seedlings to prevent the occurrence of freezing damage. 3. Prosperous growth period From the beginning of greening of seedlings to the beginning of bulb growth, the growth of seedlings is 30-40 days. The growth of roots continues to enter into the prosperous period. The number of leaves increases, the leaf area increases, the assimilation increases, and the activity of roots is strong. The nitro portion is thickened and enters the bulb expansion period. 4. Bulb expansion period From the expansion period of the bulb to the harvesting period, that is, the growth period of the bulb, the bulb grows into a longitudinal or horizontal growth, and forms an elliptic or oval-shaped small bulb. As the temperature rises, the sunshine hours increase. The growth of the leaves of the onions is inhibited, the nutrition begins to run downwards, and the bases and shoots of the leaves are stored, allowing the scales to thicken rapidly. When the roots and leaves grow in a stagnant state, the bulbs are inflated. The leaves begin to wither, the pseudo stems are soft and fall, and the outermost 1-3 layers of nutrients are transferred and dried into a film, and they enter the harvesting period. 5. Dormancy period After the onion is harvested, it enters the physiological dormancy period. This period is about 70-90 days. The length of the dormancy period is related to the storage time of the onion. The length of the onion storage time depends on the dormancy depth of the onion and the continuity of dormancy. The effect of temperature is high, the primordial group enters dormancy and the earlier the storage period is, the germination is late, so the early harvested onion is highly resistant to storage. 6. Reproductive growth period From flower bud differentiation to seed maturation, after the onion plants develop through this stage, the top buds or side buds form flower buds and bloom, and each onion can extract 2-4 flower buds. From flowering to seed maturation for 60-70 days, seeds are 1000-grain weight. 3.3 grams. Second, the requirements of onion growth for the environment 1, temperature The optimum temperature for the growth of onions is 12-26 ° C. The bulbs slowly germinate when they are around 3--5 °C, and the temperature develops rapidly above 12 °C. The optimum temperature for seedling growth is 12--20 degrees, but it can safely overwinter at a low temperature of 6---7C°. The optimum temperature for bulb expansion period is 20---26C° over 28C°. The bulb enters the physiological dormancy period. 2, lighting Onions are long-day plants that can only be formed with long sunshine and bulbs, but in shorter sunshine conditions. Even with higher temperatures, the onions will continue to grow, but the bulbs will not form in the lower part of the ground. Generally, the long-day variety must have a sunshine condition of 13.5---15 hours to form a phosphorus stem; when the short-day variety only needs 11.5---13, a longer long-term sunshine condition can meet the needs. 3, moisture Onion root system is relatively shallow, water absorption capacity is weak, soil moisture is high, and the required soil moisture is 60%-70% of the field water holding capacity. When it is less than 50%, the absorption is affected, and the water requirement during the growth period is also different. The water requirement during the growth and development of the seedlings and the bulb expansion period is relatively large, and the water should be properly controlled before the wintering of the seedlings and before the bulbs are harvested to prevent the plants from being long and resistant to storage. 4, soil and nutrition Onions require fertile soil, loose, water-preserving and fertile neutral soils are conducive to root absorption and bulb expansion. Soil compaction is not conducive to root development and bulb growth. Sand soil conservation and water retention capacity is not suitable for planting onions. Onion cultivation is suitable for neutral soil, PH value is about 6-8. Onion is a kind of fertile plant, which has high nutrient requirements for soil. Therefore, in its whole growth period, it must have sufficient nutrient supply. When seedlings are mainly nitrogen fertilizer, the bulb expansion period should increase the amount of potassium fertilizer used and promote bulbs. Inflated, phosphate fertilizer is used from the seedling stage to promote the absorption of nitrogen fertilizer and improve product quality. Third, the characteristics of fertilizer required for onion growth The leaves are the assimilated organs of the onions, and the bulbs are storage organs, so the growth of the leaves directly affects the quality and yield of the onions. Onion has a small amount of fertilizer in the seedling stage, and as the development of the aboveground part accelerates, the amount of absorbed fertilizer increases sharply. When the bulb begins to expand, the nutrients are concentrated on the onion and the leaves are lighter. From the perspective of various nutrients, potassium is most absorbed, followed by nitrogen, calcium and phosphorus. In the bulbs that store nutrients, the elemental content is the order of nitrogen, potassium, phosphorus, and calcium. The onion roots began to grow when the average temperature in the 10 cm soil layer reached 5 °C, and the root activity began to flourish at 10-15 °C. From the point of view of nutrient absorption, the winter absorption is very small, and it will increase after the spring of March of the following year. Later, as the plant grows gradually, the amount of fertilizer absorption increases accordingly. 4. Nutritional diagnosis of onion cultivation Symptoms of nitrogen deficiency on onion: the leaves are light green and grow slowly; Symptoms of phosphorus deficiency on onions: poor growth, no special symptoms on the leaves; Symptoms of potassium deficiency on onions: white to brown dead spots between the veins of old leaves, similar to those of downy mildew, should be noted; Symptoms of calcium deficiency on onions: Wide, irregularly shaped white dead spots on the top or middle of new leaves. Heart rot occurs in the middle of the bulb; Boron deficiency: the growth and development of new leaves is blocked, leaf deformity, chlorosis. Sulfur deficiency: the leaves of new leaves are light; Magnesium deficiency: light green to yellow between veins, when the onion leaves are dry. 5. Fertilization technology for onions 1. Onion seedlings The seedbed should be selected from loose and fertile soil with strong water retention capacity. The base fertilizer should be applied. Generally, 25-30kg of decomposed organic fertilizer and 0.08-0.15kg of phosphorus pentoxide should be applied in the seedling nursery of 11 square meters. The seedling stage can be combined with watering. Apply 17-20kg of manure and faeces, or 0.09-0.12kg of nitrogen to promote seedling growth. After the seedlings are planted, they are placed at 15-18 cm in the soil to form an advantageous environment for onion fertilization. The organic fertilizer is about 20-40 tons per hectare, 450-600kg of plant ash can be applied to the acidic soil, and 55-90kg of phosphorus pentoxide is added to the field with insufficient phosphate fertilizer. After the onion slows down the seedlings and enters the growth period of the stems and leaves, in order to supplement the nutrition, it is necessary to grasp the first fertilizer, apply 15-19 tons of manure per hectare, or about 30-45kg of nitrogen fertilizer. Bulb expansion period should be applied 2-3 times "priming fertilizer", applying EM bacterial fertilizer 45-60kg per hectare or 30--50Kg of Bacillus subtilis. 2, onion fertilization method First, it can be applied at the seedling stage, and then watered immediately, without delay. The second is to apply fertilizer, combined with irrigation and fertilization. The third is foliar spray fertilizer; 40-40 days after planting, foliar spray fertilizer (root dressing). When the onion bulbs are transferred to the expansion period, it is important to topdress the fertilizer, which has a significant effect on increasing the onion. When we are topdressing, we must pay attention to the quantity and quality of onions, and pay attention to the optimum period of topdressing. If the key fertilization time is too late, the bulb will not be adequately nutritious when it is swollen rapidly, and the maturity period will be delayed. It will not be transferred to dormancy in time, affecting the yield of onion, and it is not conducive to storage. If the key topdressing is too early, the aboveground leaves are easy to grow. Therefore, it is not conducive to the expansion of the bulb. Six, onion spring field management points 1, timely watering and topdressing As the temperature rises, the onion begins to enter the growing season, and the leaf area will expand rapidly. At this time, the focus of management is to promote the vigorous growth of the leaves and lay the foundation for bulb expansion. To this end, it should be timely watering and topdressing. It is recommended to pour water once every 10 days, combined with watering, 25 to 30 kg of potassium sulfate type compound fertilizer per acre, when the plant grows to 8-9 pieces of functional leaves. Cultivate seedlings. It can be sprayed with Pridden fish protein or seaweed 600 times solution on its foliar surface, which can promote the expansion of onion bulbs and prevent the lengthening. 2, seedlings The onion enters the bulb expansion period. During this period, the temperature rises, the plant growth rate increases, and the water evaporation begins to increase. At this time, watering should be diligent. Generally, water is poured once every 5 to 7 days, and 10 to 15 kg of fertilizer is applied by nitrogen, phosphorus and potassium. When the bulb is close to maturity, the physiological functions of the leaves and roots begin to decrease. The watering should be gradually reduced. The watering should be stopped 7 to 8 days before harvest to reduce the water content in the bulb and improve the storability. 3. Prevention and treatment of diseases The diseases that are easy to occur on onions are mainly anthracnose, soft rot, and gray mold. In order to reduce and prevent the occurrence of diseases, in addition to strengthening daily management, it should also be combined with chemical control, spraying in advance, and preventing. When anthrax occurs in the leaves, there are fusiform to irregular lesions, light grayish brown to brown, with many small black spots. After the lesion is enlarged, the upper leaf is killed. When the temperature reaches about 20 °C, the onion high-humidity condition is heavier, and the chemical control can use 75% Dakening WP 600 times solution, 10% Shigao water granule 1500 times solution or 70% methyl thiophanate 500 times. Liquid + fish protein 600 times liquid spray, spray once every 7 to 10 days, even spray 2 to 3 times. The above is an introduction to the high-quality and high-quality cultivation techniques of onions. The above analysis of all aspects of onion cultivation is also to better understand the onion planting. I hope that the content shared by Xiaobian can help the majority of onion growers. We. Household Medical Equipment,Power Wheelchair For Disabled,Nursing Home Care Bed,Medical Equipments For Disabled Patient Haloxylon Ammodendron Medical Equipment Co., Ltd. , https://www.ssmedicaldevic.com
