First, onion cultivation management
Onion cultivation and management must start with sowing and seedling raising.
First, sow and raise seedlings
1, suitable sowing date
Onion cultivation has strict seasonality. The climate in different areas is different, so we must pay attention to choosing the right sowing time. If sowing is too early and the seedlings are too large, the probability of bolting early in the next year will increase. Sowing is too late, the seedlings are too small, the wintering ability is poor, the growth period is shortened accordingly, the onion can not fully expand, and the yield is low.
2. Seed treatment
In order to have confidence, the purchased onion seeds can germinate first to know the quality of the seeds. In order to facilitate germination and early emergence, it is best to soak the seeds before sowing.
Soak onion seeds in cold water for about 12 hours, then take them out, wrap them in wet cloth and put them at 20? Accelerate germination at 22℃, rinse with clear water every day, and sow in time when the seeds turn white, otherwise the radicle of onion seeds will be too long and easily broken during sowing.
3, seedling management
Onion seeds can be drilled, and the soil should not be too thick. Generally seeds can be covered. You don't need to water it before it is unearthed, but you can cover it with crop straw to keep it moist. After the seedlings began to be unearthed, the mulch was gradually removed, so that the seedlings had an adaptation process without losing water and wilting.
Watering at seedling stage depends on soil moisture and sowing method. If the wet sowing method is adopted, because the soil moisture is sufficient, it is not necessary to water the seedlings before they are completely sown. Onions sown by dry sowing method should be watered once before the cotyledons become straight, watered once after the cotyledons become straight, and watered once again until the first real leaves grow.
After the seedlings grow the second true leaf, nitrogen fertilizer can be applied once with water, and urea per mu is about 10 kg, or human manure can be applied. After the second real leaf grows, before topdressing, the relatively weak seedlings should be removed and weeds should be pulled out at the same time.
Onion seedlings are sown in autumn, not in seedbeds before. Generally, it is necessary to water the land for wintering once before it freezes, and at the same time, a wind barrier can be erected on the north side to keep warm and cold. As the temperature drops, crop straws such as wheat straw can be covered on the border to prevent freezing. When the temperature rises in the next spring, it can be peeled and the seedlings can turn green.
Second, colonization.
1, planting time
The planting time of onion varies with different planting areas, some in spring, some in late autumn and some in early winter. In a word, in the suitable planting period, the varieties of early-maturing onion should be advanced appropriately, and planting old seedlings will seriously affect the yield. Planting as early as possible in spring can prolong the growing period.
2. Soil preparation and fertilization
Before ploughing the land, sufficient base fertilizer should be applied, and the ploughing depth should not be less than 20 cm. Because the roots of onion are shallow, most of them are distributed in the soil layer of about 20 cm, which requires higher soil. Poor soil preparation will affect root development and premature senescence of lower leaves.
3. Colonial Law
Before the emergence of onion seedlings, we should gently water and pull out the seedlings to prevent root damage, and pick out the diseased seedlings, dwarf seedlings, clumped seedlings, yellowing atrophy seedlings and root rot seedlings. For big seedlings, one third of the leaves can be cut off before planting, which reduces the possibility of early bolting. Make sure that the roots of the seedlings are wet before planting. Can the onion cultivated with plastic film cover be cut at the root of 1? About 2 cm.
Onions are suitable for close planting. In a certain range, the yield increases with the increase of density, but it will not increase after reaching a certain level. Generally, it is 36,000 mu. About 42,000 plants. The density of early-maturing varieties can be increased appropriately, otherwise it will be low. In order to improve the rooting ability of onion after colonization, it can be used before 10 colonization. /kloc-foliar spraying potassium dihydrogen phosphate solution for 0/5 days.
What is the planting depth of onion? 3 cm is appropriate, too deep planting, onion sphericity is high, leading to yield reduction. If it is too shallow, it is easy to lodging, and onions are easy to crack when exposed to the soil. Planting should be shallow in spring, slightly deeper in winter, slightly deeper in sandy soil and shallow in cohesive soil.
Third, post-colonial management.
1, fertilization
After the onion seedlings turn green, the first topdressing should be carried out to supplement nutrition for the root growth of the seedlings and lay the foundation for the vigorous growth of the aboveground parts in the future. Onions cultivated with plastic film mulching can be applied with diammonium phosphate or ternary compound fertilizer.
When the onion begins to swell, start topdressing the swelling fertilizer, which can be chased by 2? Third, in the middle stage of onion expansion, the amount of topdressing should be large, more potassium fertilizer should be applied, and less nitrogen fertilizer should be applied to avoid greedy and cheap growth.
water
If the onion is planted before winter, it should be watered with frozen water before wintering, and then with green water in the next spring. Water that turns green should be watered at the right time, and the soil temperature should be lowered too early, which is not conducive to the growth of onions. If it is too late, it will inhibit the growth of onion and cause the leaves to be dry and sharp.
Onions planted in early spring take about 20 days from planting to the end of slow seedling. During this period, the water demand is limited, so it is necessary to water with a small amount of water frequently. Too much watering will reduce the ground temperature, which is not conducive to root growth. After slow seedling, it is necessary to properly control water, squat seedlings, promote rooting and prevent virtual growth. After squatting, water is usually poured once a week to keep the soil moist to promote the growth of the above-ground parts.
When the onion begins to swell, it is necessary to control the water and squat seedlings. The length of squatting seedlings should be flexibly controlled according to the soil, climate and plant growth. Generally speaking, when the sandy soil or climate is dry, the time of squatting seedlings should be shortened appropriately, and when the clay is low and rainy, the time of squatting seedlings should be extended appropriately. The purpose is to promote the expansion of onions, and the general squatting time is about 10 days.
It is generally believed that when the outer leaves of onion turn dark green, the fleshy leaves are thick, the wax on the leaves increases, and the color of the heart leaves deepens, which is the sign of ending squatting seedlings. After squatting, water is usually poured every five days or so to promote onion expansion. When some plants in the field fall down, stop watering to avoid storage intolerance after harvest.
3, intertillage and soil cultivation
Onions cultivated without plastic film mulching must be planted after intertillage. The frequency of intertillage in clay is more than that in sandy loam, and the depth of intertillage is shallow, especially near plants, to prevent root damage. Stop intertillage after ridging, and properly cultivate the soil during intertillage.
Onions cultivated with plastic film mulching do not need intertillage cultivation.
B, matters needing attention
1, seedling selection
It is best to choose onion seedling belt 3? Four real leaves were planted, and the seedling height was about 30 cm.
2. Suitable sowing date
The sowing and seedling raising time of onion must be well grasped, otherwise it will easily lead to bolting in advance and affect the yield and quality.
3, the correct management of fertilizer and water
Onions planted in autumn should not be watered and fertilized too much before winter, otherwise it will lead to early differentiation of flower buds and increase the probability of bolting in advance. Don't control too much water at seedling stage.
4, pay attention to the prevention and control of pests and diseases, to prevent the onion from rotting roots and damaging leaves.
This is how onions are planted and managed. In the actual training process, it is far more troublesome than I said. What you get from the newspaper is superficial. If you want to know this, you have to plow the fields, pay tribute to my hometown and pay tribute to all hardworking farmers!