1. Nursery and Seedbed Preparation: The nursery soil was carefully prepared by mixing garden soil that had not been used for planting in the past three years with high-quality decomposed organic fertilizers, making up 30% to 40% of the mixture. To ensure a healthy start, the soil was sterilized using a combination of 50% carbendazim wettable powder and 50% thiram wettable powder. Additionally, 50% phoxim EC was added to the irrigation water at the bottom of the seedbed to manage underground pests effectively.
2. Sowing Period: In the Lianyungang area, the ideal sowing window is between September and October, with a recommended seeding rate of 150-200 grams per 667 square meters.
3. Seed Treatment: Before planting, seeds were air-dried for 8 to 10 hours to enhance germination rates and improve seed viability.
4. Seeding: The seedbeds were constructed to be 1.0 to 1.5 meters wide and 10 to 15 meters long, ensuring a level and fine surface. A layer of water was poured into the bed, penetrating about 8 to 10 cm into the soil. Once the water had soaked in, dry seeds were evenly distributed and covered with a thin layer of soil (about 1 cm thick). The sides were then filled with fine soil to maintain consistency.
5. Seedbed Management: To protect young seedlings from harsh environmental conditions, straw or shade nets were used to cover the beds, helping retain moisture, reduce sun exposure, and prevent erosion. Watering was avoided until the seedlings emerged. When approximately 70% of the seedlings had emerged, the covering was removed in the evening to avoid stress and yellowing. It typically took 7 to 10 days for the seedlings to be ready for transplanting. Weeding was done 2 to 3 times during the early stages, especially after the seedlings developed two leaves. If the seedlings appeared weak, a small amount of irrigation was provided, along with 5 kg of urea per 667 square meters.
6. Pest Control at Seedling Stage: To control tobacco budworm, a 50% phoxim emulsifiable concentrate diluted at 800 times was sprayed. For bacterial damping-off, a solution of 72% agricultural streptomycin soluble powder diluted at 2000 times was applied. These treatments were repeated every 7 to 10 days for 2 to 3 cycles. 2. Transplanting:
1. Transplanting Time: Seedlings were ready for transplanting when they had developed 3 to 4 true leaves, which usually occurred around 55 to 60 days after sowing.
2. Field Preparation: Fields previously planted with onions or garlic were avoided for at least 2 to 3 years to minimize disease risk. Each 667 square meters received 4000 to 5000 kg of well-decomposed organic fertilizer, along with 50 kg of phosphorus and potassium fertilizer. The soil was deeply tilled to a depth of 20 cm to ensure even distribution of nutrients. After leveling, raised beds of 1.2 to 1.5 meters in width were created, depending on the mulch size. Mulch was laid 4 to 5 days before transplanting, and 150 ml of 48% trifluralin was sprayed per 667 square meters to suppress weeds. The mulch was compacted to prevent wind damage during winter.
3. Transplanting: One to two days before planting, the seedbed was watered to ease the transplanting process and reduce root damage. Healthy, disease-free seedlings were selected and transplanted in different sizes (large, medium, small), with a spacing of 15 cm x 13 cm, resulting in 22,000 to 25,000 plants per 667 square meters. After planting, a thorough irrigation was conducted to settle the roots. 3. Field Management:
1. Winter Protection: No fast-acting fertilizers were applied before winter. Before the arrival of a major cold front, the field was flooded with cold water to protect the plants from freezing. Throughout the winter, the soil was kept moist to prevent the seedlings from drying out or suffering from frost.
2. Leaf Growth Phase: During mid-to-late March of the following year, onion seedlings began to regreen. At this stage, shallow cultivation was performed, followed by an application of 20 kg of urea per 667 square meters. By early April, the leaves entered their vigorous growth phase, and an additional 20 kg of urea and 20 kg of phosphorus-potassium compound fertilizer were applied to meet the nutrient demands.
3. Bulb Expansion Phase: From late April to mid-May, the leaves stopped growing, and the plant's energy shifted to bulb development. During this period, the demand for phosphorus increased significantly. Applying 30 kg of phosphorus-potassium compound fertilizer or diammonium phosphate per 667 square meters ensured proper bulb expansion. Regular watering, every 10 to 15 days, was essential to maintain soil moisture.
4. Pest and Disease Control: Major threats to yellow onions include thrips, purple spot, and downy mildew. Prevention and early intervention are key. Thrips can be controlled using 25% fennel chrysanthemum vinegar or 20% speed killing ding diluted at 2000 times. Purple spot can be managed with 75% white bacteria at 600 times or 70% mancozeb at 500 times. Downy mildew can be controlled with 50% acetaminophen diluted at 1000 times. These sprays should be applied every 7 to 10 days for 2 to 3 consecutive rounds. Crop rotation every 3 to 4 years is also recommended to reduce disease buildup. 4. Harvesting and Post-Harvest Handling: Two weeks before harvest, the above-ground leaves were sprayed with 2,500 mg/L qingshui (MH) at a rate of about 120 kg per 667 square meters to prevent sprouting during storage. When the leaves were still green, the tubular leaves were harvested 5 to 7 days after natural lodging. Harvesting should take place on sunny days to promote drying. After pulling up the onions, they were left on the surface to dry for 1 to 2 days, allowing the false stems to soften and detach. The remaining stems were cut to 2 to 3 cm or left intact if fully matured. After harvesting, the onions must be dried thoroughly, either by hanging or stacking in open areas. During storage, they should be turned 2 to 3 times, and any damaged bulbs should be removed promptly to prevent the spread of disease. Frozen Fish,Frozen Bonito Tuna,Frozen Mackerel Fish,Fresh Frozen Mackerel Fish ZHEJIANG RETRONX FOODSTUFF INDUSTRY CO.,LTD , https://www.retronxfoods.com
Non-pollution Cultivation Techniques of Huangpi Onion