What is the fertilizer for green onions?

No matter what crops should be fertilized reasonably, the basis of rational fertilization is determined according to soil characteristics, planting environment and fertilizer demand characteristics, and green onions are no exception. So, what fertilizer is good for green onions? First of all, we should understand the fertilizer demand characteristics of green onions, and then choose the fertilizer suitable for the growth of green onions according to the local actual planting situation, so that the production of green onions can obtain higher yield and quality.

First, the characteristics of fertilizer demand of green onions

1, requirements of green onions for growth environment

The root of scallion is a white linear fibrous root with uniform thickness and few lateral roots. Although the ability of absorbing fertilizer is weak, it needs more fertilizer and belongs to fertilizer-absorbing crops. The temperature required for the growth of Chinese onion is 7~35℃, but the most suitable temperature for the growth of Chinese onion is 19~25℃, and it grows fastest in this temperature range. Welsh onion is drought-resistant and waterlogged-resistant, with strong water retention and low water consumption; Welsh onion is not strict with light, so long as the plant can survive vernalization normally, it can bolt and bloom normally in short and long sunshine. Welsh onion has low requirements on soil, and the soil suitable for the growth of Welsh onion is PH7~7.4.

2. Nutritional requirements of green onions

Generally speaking, per 1000 kg of green onion needs to absorb 2.5~3 kg of pure nitrogen, 0.5 ~ 1.2 kg of pure phosphorus and 3.3~4 kg of pure potassium, from which it can be seen that green onion needs potassium fertilizer most, followed by nitrogen fertilizer and phosphorus fertilizer least. Among the three elements, scallion is the most sensitive to nitrogen, and reasonable application of nitrogen fertilizer can obviously increase the yield of scallion.

Among the medium and trace elements, scallion is sensitive to calcium, sulfur, boron and manganese. In particular, the pungent taste of sulfur and green onions is due to sulfide. Therefore, if the green onion lacks sulfur during its growth and development, it will inhibit the synthesis of sulfide, thus reducing the quality of green onion. Therefore, when topdressing green onions, it is best to choose sulfur-containing fertilizers, such as potassium sulfate, which can supplement other nutrients while supplementing sulfur, thus improving the flavor of green onions.

The nutrient absorption of green onions at different growth stages is also different. Green onions planted in northern China are sown in autumn and spring, and generally harvested in June165438+1October of the following year.

Because the overwintering Chinese onion seedling is in winter, its growth is small, and its absorption of nutrients is correspondingly less. If the base fertilizer is fully applied, no additional fertilization is needed, but excessive fertilization will cause ineffective growth, which is not conducive to the smooth overwintering of green onions. After turning green in spring, it is the most vigorous growth period of Chinese onion seedlings, and it is also the key period for the formation of strong seedlings. If it is the production of green onions, it is also the key time for the formation of green onion yield. Therefore, more fertilizer is needed.

Generally, planting begins in June of the following year. After planting, the scallion enters the formation period of scallion. At the beginning, because it was the growth recovery stage, the amount of fertilizer needed was not much, but as the weather turned cold and the temperature difference increased during the day, the growth rate began to accelerate. Therefore, this stage is also a critical period of fertilizer demand, and it is also a period of soil softening and yield formation. 1 1 or so, due to the sudden drop in temperature, the growth of Welsh onion plants also stopped, the leaves and roots gradually aged, and the nutrient absorption decreased rapidly.

Second, the fertilization method of green onions

Welsh onion is suitable for planting in fertile soil with deep soil layer and strong water and fertility conservation. Because of the long growth period, in addition to adequate base fertilizer, it is necessary to apply topdressing several times in different growth periods to ensure the robust growth of plants.

1, green onion base fertilizer

Before soil preparation, the base fertilizer is spread into the soil, and the soil and fertilizer are fully mixed. About 3500 kilograms of decomposed organic fertilizer, 40 grams of calcium superphosphate and 20 kilograms of potassium sulfate are applied per mu, and plant ash 100 kilograms can be applied in areas where conditions permit. In addition, in order to ensure nutrient balance, 2 grams of copper sulfate and boric acid 1 kg can be applied per mu when applying base fertilizer.

2. Top dressing of green onions

Topdressing should be combined with intertillage, soil cultivation and watering of green onions, and the principle of grasping is light before, medium before and supplementary after.

Fertilization period is around the solar term of Bailu, which is the vigorous growth period of Welsh onion leaves. Through fertilization, the growth of leaves can be ensured, thus improving the yield and quality of green onions. For the first topdressing in early autumn, 3000~4000 kg of soil miscellaneous fertilizer or cake fertilizer 150~200 kg per mu can also be applied with nitrogen fertilizer, such as urea 15 kg.

The second topdressing should start in the summer solar term. This topdressing should be supplemented with phosphorus and potassium fertilizer, and 50~ 100 kg cake fertilizer, 30 kg calcium superphosphate and plant ash 100 kg can be applied per mu, and intertillage after fertilization.

It is an important period for the formation of scallion to enter the full bloom stage. Because of the large growth of scallion, it needs more nutrients, so topdressing can be done once in Bailu and autumnal equinox to promote the flowering of scallion. Therefore, in the Millennium season, the third topdressing is mainly nitrogen fertilizer and potassium fertilizer, with urea 10~ 15 kg, plant ash 100 kg or potassium sulfate 10~ 15 kg per mu. For the fourth topdressing in autumn equinox season, urea 15 ~ 20kg or compound fertilizer 20 ~ 30kg, plant ash 100kg or potassium sulfate 10 ~ 15kg can be applied per mu.

The fibrous roots of scallion have the characteristics of fat, water and temperature. Therefore, scientific and reasonable fertilization can be carried out in combination with this feature. A farmer friend summed it up very well. Sprinkle, earth pressure and water beside the roots? . That is to say, when applying fertilizer, the fertilizer should be evenly spread on the topsoil of the root of Chinese onion, and then the soil should be cultivated and covered with fertilizer, which can reduce the loss of nutrients and promote the absorption of nutrients by fibrous roots, thus promoting the softening growth of Chinese onion and improving the stress resistance of plants. Watering within two days after soil tillage is beneficial to the dissolution of fertilizer and accelerates the absorption of nutrients by green onions.

In order to improve the stress resistance of seedlings, it is necessary to supplement nutrients by topdressing outside the roots. In production, plant ash filtrate can be sprayed on leaves. The specific method is to dissolve 8 kg of plant ash in 15 kg of water, filter it, and then spray it on the page with 150 kg of water every 7~ 10 days for 2~2 consecutive times. You can also spray 0.2% potassium dihydrogen phosphate solution through the page to enhance the growth potential of seedlings and improve the disease resistance and wind resistance of plants.

In the process of fertilization, according to the nutrient demand and growth characteristics of green onions, as well as soil fertility and climate characteristics, fertilization should be scientific and reasonable. Only in this way can we promote the normal growth and development of green onions and obtain higher yield and quality.