The law of fertilizer requirement for green onions
Before wintering, because of the low temperature, the seedling growth is small, and the amount of fertilizer needed is small. Therefore, in the case of applying the base fertilizer to the seedbed, generally no fertilization is required, and too much fertilizer will cause the seedlings to grow long, which is not conducive to wintering. From wintering to rejuvenation, due to the extremely small amount of growth, the seedlings are basically in hibernation, and the amount of fertilizer required is also very small. After returning to green, the seedlings enter the peak period of growth, which lasts for 80-100 days. It is a key period for cultivating strong seedlings for winter onions. For the production of shallots, it is a key period for the formation of yield, and the amount of fertilizer is more. After planting the field, it will enter the formation period of scallion, the initial growth is in the recovery stage, the amount of fertilizer is small, and it enters the vigorous growth period after the autumn cool, and the most fertilizer absorption is the season for the formation of winter onion, which is also the key period for fertilizer and water management. At this time, it should prevent excessive fertilization, otherwise it will affect the storage performance of winter onion.
The green onion is more fertile and sensitive to nitrogen. The application of nitrogen fertilizer has obvious yield increasing effect. The nutrient uptake is highest in potassium, followed by nitrogen and phosphorus, and the ratio of N:P2O5:K2O is 1:0.4:1.3. In addition to nitrogen, phosphorus and potassium, nutrients such as calcium, zinc, manganese, boron and sulfur have certain effects on the yield and quality of green onions. The addition of fertilizers containing these elements can increase the growth of scallions and increase the yield and taste.
Scientific fertilization technology
1. Apply enough base fertilizer: Green onion requires deep soil layer, water and fertility to maintain fertile soil. Because of its long growth period, in addition to the need for sufficient base fertilizer, it is necessary to carry out multiple topdressing in different growth stages. Fertilization of winter onion is divided into two parts: seedbed fertilization and field fertilization. The seedbed fertilization is mainly based on base fertilizer, 3000-4000 kg of compost or manure per acre, 30-40 kg of superphosphate, 20 kg of potassium sulfate or 100 kg of ash, which is applied before the land preparation and ploughed into the soil, then shallow tillage Hey, mix the organic fertilizer with the soil.
2. Skillful application of top dressing: The first top dressing before and after the fall, 20 yuan of ternary compound fertilizer per acre, 5 kg of urea; the second top dressing in late August, 20 yuan of ternary compound fertilizer per acre, urea 75 kg; the third top dressing in late September, 25 yuan per mus of ternary compound fertilizer, 12 kg of urea.
3. Foliar sprayed potassium: In order to strengthen the disease prevention ability of onion seedlings, the plant can be sprayed with grass ash to add potassium fertilizer, 8 kg of grass ash per acre is dissolved in 15 kg of water, and the filtrate is then 150 kg of water, and the foliage is sprayed. Spray once every 7-10 days and spray 2-3 times continuously. It can also be sprayed with 0.2% potassium dihydrogen phosphate solution to increase the growth potential of onion seedlings and improve disease resistance and wind resistance.
(Pan Jilan)
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