A, onion cultivation management
The cultivation and management of onion must start with sowing and seedling raising.
First, sowing and seedling raising
1, suitable sowing time
Onion cultivation has strict seasonality. The climate in different regions is different, so we must pay attention to choosing the appropriate time for sowing. If sowing is too early, the seedlings will be too large, and the probability of early bolting will increase in the next year. If sowing is too late, the seedlings will be too small, the wintering ability will be poor, the growth period will be shortened accordingly, the onion will not be fully expanded, and the yield will be low.
2, seed treatment
In order to be confident, the purchased onion seeds can be germinated first to understand the quality of the seeds. In order to facilitate germination and early emergence, it is best to soak seeds before sowing.
Soak the 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 are white, otherwise, the radicle of onion seeds will be too long and easily broken during sowing operation.
3, seedling management
Onion seeds can be drilled and sowed, and the soil should not be too thick. Generally, the seeds can be covered. Before being unearthed, it is not necessary to water them, but crop straws can be used to cover them for moisturizing. After the seedlings begin to be unearthed, the mulch is gradually removed, so that the seedlings have an adaptive process and do not lose water and wilt.
Watering at seedling stage depends on soil moisture and sowing methods. If wet sowing method is adopted, it is not necessary to water before the seedlings are fully sown because of the sufficient soil moisture. Onions sown by dry sowing method should be watered once before the cotyledons are straightened, and then watered again when the cotyledons are straightened, and then not watered again until the first real leaves grow.
After the seedlings grow the second true leaf, nitrogen fertilizer can be applied once with water, with urea 10 kg per mu, or human excrement and urine can be applied. After the second real leaf grows, before topdressing, it is necessary to remove relatively weak seedlings and pull out weeds at the same time.
Onion seedlings are sown in autumn, and they are not planted in the seedbed before the year. Generally, the overwintering water should be poured once before the land is frozen, 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 off and the seedlings can turn green.
Second, colonization
1, planting time
The planting time of onion varies with different cultivation areas, some in spring, some in late autumn and some in early winter. In short, in the appropriate planting period, early-maturing onion varieties should be advanced appropriately, and planting aged seedlings will seriously affect the yield. Planting in spring should be as early as possible, which can prolong the growth 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 onions are shallow, most of them are distributed in the soil layer of about 20 cm, which requires higher soil. If the soil preparation is not fine, it will affect the development of root system, and the lower leaves will premature aging.
3, colonization method
Before the onion seedlings emerge, they should be watered lightly, and the seedlings should be gently pulled out to prevent root damage, and the diseased seedlings, dwarfed seedlings, overgrown seedlings, yellowing atrophied seedlings and root rot seedlings should be picked out. For large 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 seedlings are wet before planting. Onions cultivated with plastic film mulching can be cut at 1? About 2 cm.
Onion is suitable for close planting. Within a certain range, the yield increases with the density, but it will not increase after a certain degree. Generally, it is 36,000 mu. About 42,000 plants. The density of early-maturing varieties can be appropriately increased, otherwise it is low. In order to improve the rooting ability of onion after colonization, it can be used before colonization 10? /kloc-foliar spraying potassium dihydrogen phosphate solution for 0/5 days.
The planting depth of onion is 2? 3 cm is appropriate, the planting is too deep, and the onion is high spherical, resulting in reduced production. If it is too shallow, it is easy to lodging, and the onion is easy to crack when exposed on the soil surface. Planting should be shallow in spring, slightly deeper in winter, slightly deeper in sandy soil and shallower in sticky soil.
Third, the management after colonization
1, fertilization
After the onion seedlings turn green, topdressing should be carried out for the first time to supplement nutrition for the growth of seedling roots and lay the foundation for the vigorous growth of aboveground parts in the future. Onions cultivated with plastic film mulching can be combined with water application of diammonium phosphate or ternary compound fertilizer.
When the onion starts to swell, start topdressing the swelling fertilizer, which can be chased by 2? Three times, in the middle stage of onion swelling, the amount of topdressing should be large, more potash fertilizer should be applied, and less nitrogen fertilizer should be applied to avoid greed for youth and vain growth.
Step 2: water
If the onion is planted before winter, it should be watered with frozen water before wintering, and then watered with green water in the spring of the following year. Water turning green should be poured at the right time, which will reduce the soil temperature too early, which is not conducive to the growth of onions. If it is too late, it will inhibit the growth of onions and cause dry tips in the leaves.
The onion planted in early spring takes about 20 days from planting to the end of slow seedling. In this period, the water demand is limited, so it should be watered frequently with small water. Excessive watering will reduce the ground temperature and is not conducive to the growth of roots. After slow seedling, it is necessary to properly control water, squat seedlings, promote rooting and prevent vain growth. After squatting, water is usually poured once a week to keep the soil moist, so as to promote the growth of the above-ground parts.
When the onion begins to swell, it is necessary to control the water and squat the seedlings, and the length of squatting time should be flexibly mastered according to the soil, climate and plant growth. Generally speaking, when sandy soil or climate is dry, the time of squatting seedlings should be shortened appropriately, and when clay soil is low-lying and rainy, the time of squatting seedlings should be extended appropriately. The purpose is to promote the expansion of onion, and the general squatting time is about 10 day.
It is generally believed that when the outer leaves of onion turn dark green, the mesophyll is thick, the wax on the leaves is increased, and the color of the heart leaves is deepened, which is the sign of ending squatting seedlings. After crouching seedlings, water should generally be poured every five days or so to promote the expansion of onion. When some plants in the field fall, stop watering to avoid storage intolerance after harvest.
3, intertillage and cultivate soil
Onions that are not cultivated with plastic film mulching must be cultivated in intertillage before squatting. The frequency of intertillage in clay soil is more than that in sandy loam soil, and the depth of intertillage is shallower, especially near the plants, to prevent root damage. Stop intertillage after the plants are ridged, and properly cultivate the soil while intertillage.
Onions cultivated with plastic film mulching do not need to be cultivated in intertillage.
B, matters needing attention
1, selection of seedlings
It is best to choose onion seedlings with 3? Four true leaves and strong seedlings with a height of about 30 cm were planted.
2, the appropriate sowing date
The sowing and seedling raising time of onion must be well grasped, otherwise it will easily lead to early bolting 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 early bolting. Don't control water too much at seedling stage.
4, pay attention to the prevention and control of pests and diseases, to prevent the phenomenon of rotten onions and damage to leaves.
This is the way of onion planting and management. In the actual cultivation process, it is far more troublesome than what I said. What you get from the paper is shallow. If you want to know this, you must plow, pay tribute to my hometown and pay tribute to all hardworking farmers!