First, the choice of planting plots
Onion is a kind of crop that can't tolerate continuous cropping, and it is easy to cause soil-borne diseases. Therefore, when planting green onions, it is best to rotate with non-green vegetables for 2-3 years. Generally, it can be rotated with wheat, cabbage and potato, which can effectively reduce the occurrence of soil-borne diseases.
Planting plots should be sandy loam plots with flat ground, deep soil layer, loose texture, medium fertility and convenient water supply and drainage.
Second, soil preparation and fertilization
After the previous crop is harvested, it is necessary to dig deep and dry the soil in time to kill germs. Combine with soil preparation, applying 4,000-5,000 kg of decompose high-quality farmyard manure per mu, and ditching after combining with soil moisture, wherein that width is 15-30cm and the depth is 20-30cm；; If it is a variety with false stems, it can be ditched with a depth of 40~50 cm and a width of 30~40 cm. When ditching, keep one side vertical, which can effectively avoid the long bending of onion seedlings.
The row spacing of green onions varies with varieties. The suitable row spacing standard is about 1.5 times of the length of the pseudostem, and the row spacing of Changbai Welsh onion is generally 70~90 cm. The row spacing of short white onions is 50~60 cm.
Combined with ditching, organic fertilizer or cake fertilizer 50 ~100kg, compound fertilizer10 ~15kg, calcium superphosphate 30 ~ 50kg and potassium sulfate10 ~15kg were applied to each mu of centralized ditch. Then dig deep into the bottom of the ditch to mix the soil and fertilizer evenly.
Combined with a given planting ditch fertilization, 5% poison per mu? Use 3~4 kilograms of phoxim granules or 200 grams of Lethbone EC and 200 grams of potassium dihydrogen phosphate to 20 liters of water to control underground pests such as onion flies.
Third, onion seedling treatment
1, green onions emerge.
Sowing should be determined according to the soil moisture of the seedbed. If the seedbed drought is not conducive to seedling emergence, it can be watered 1~2 days before sowing, and seedlings can emerge when the dry humidity is suitable. Without watering, you can hold the roots of onions by hand, or pick up seedlings with shovels and forks. Be careful not to damage the roots when raising seedlings. After seedling raising, shake off the soil on the roots, then remove the dead leaves and the disabled, infected and other plants that are not conducive to colonization. Finally, plants should be discharged in order.
2. Classification of Welsh onion seedlings
Generally speaking, onion seedlings in seedbeds are of different sizes. If all of them are planted in this way, it will definitely not be conducive to field management in the later stage. Therefore, onion seedlings should be divided into first-class seedlings and second-class seedlings according to their size. Bundle the seedlings according to their grades and cover them properly during transportation to avoid strong light. Onion seedlings that have not been planted on that day should be stored in a cool place with their roots down, and should not be piled up to avoid rotting seedlings due to breathing and cooling at night.
Fourth, onion colonization.
1, leaf cutting and field planting
Planting Chinese onion leaves in field can reduce the transpiration of Chinese onion leaves after field planting, promote seedling delay and increase yield. The specific method is: after pulling out the onion seedlings, align the roots and tie them neatly, then cut off the upper leaves with a knife, leaving about 10 cm of fake stems and onion leaves, and planting them immediately after cutting the leaves.
2. Planting density
The reasonable density shadow of onion planting depends on variety characteristics, soil fertility, onion seedling size and planting time. Generally speaking, the planting distance is 4~7 cm. The basic principles to grasp the planting density are: generally, long white scallions are per mu18,000 plants, and short white scallions are 25,000 plants. If you plant early or choose large seedlings, you can plant small seedlings thinly, late or densely.
3. Planting method
Bundle graded green onions and put them on the ridge section by section, and plant seedlings of the same grade in the same section. At present, the main planting methods are transplanting and placing.
(1), planting method
Planting methods can be divided into two ways: dry planting method and wet planting method.
Wet insertion method: Now irrigate the onion ditch, and insert the onion in a single line based on the center line of the bottom of the ditch after infiltration under water. Hold the onion seedlings left and right, place the roots at the bottom of the ditch according to the plant spacing, and put the onion root cutting into the soil with the onion fork in the right hand, and lift it up slightly to spread the roots and keep the onion seedlings straight. Leave the jack after insertion to promote ventilation. After insertion, cultivate the soil on both sides of the onion seedlings and step on them tightly. The advantages of this method are high planting speed and good verticality of green onions. It should be noted that before planting, the soil plane in the planting ditch should be soft to facilitate seedling transplanting. Dry insertion method: it is the method of inserting onions before watering. 2, pendulum planting method
Onion plants are placed on one side of the ditch wall in the planting ditch according to the plant spacing, and the ridge direction is north-south direction on the west side of the ditch wall, and the ridge direction is east-west direction on the south side of the ditch wall to reduce sunlight exposure. 1 After ditching, immediately take the trench bottom soil with a hoe and bury the root 7- 10 cm thick. Then pour the water to stabilize the seedlings or plant them. The water flow should be slow, and don't wash the onion seedlings down. After water permeates, thin soil should be covered to keep moisture.
The advantages of pendulum planting method are faster planting speed and faster seedling extension, but the base of the planted fake stem of Chinese onion is easy to bend, which affects the commercialization of Chinese onion. Therefore, it is suggested to adopt transplantation for colonization.
No matter which planting method is adopted in the end, the suitable depth is 7~ 10 cm, and it is better to cover the soil without burying the onion core. Too deep planting is not conducive to rooting and germination, and too deep planting is easy to cause plant death. Too shallow planting can easily lead to lodging after planting, which is not conducive to soil cultivation. When the height of onion seedlings is inconsistent, we should grasp the principle of uneven up and down. In addition, in order to facilitate close planting, plant light transmission and later field management, the onion leaf sector should be perpendicular to the ridge direction or 45? Horn.
3~5 days after planting, according to the actual soil moisture, water 1 time slow seedling, and then squat seedlings in intertillage. At this point, the planting and transplanting of green onions ended and entered the growth period.
When transplanting green onions, we must operate carefully according to the actual planting situation, because the quality of transplanting directly determines the later growth of green onions and the convenience of field management.