The types of vegetables included in the onion and garlic category include leeks, garlic, green onions, onions, scallions, chives, etc. They are all perennial herbaceous plants of the genus Allium in the Liliaceae family, and have a special odor. Cultivation Season: Green onions have a wide adaptability to temperature. Green onions can be harvested and supplied at any time before they grow into stems. Therefore, the growth period can be long or short. Taking advantage of these characteristics, green onions can be sown in stages and supplied year-round. Sowing can be done from January to October in south subtropical areas, but it is usually sown in spring and autumn. For example, in the Panzhihua area, spring sowing is sown from March to April, planting is done from April to May, and large quantities are put on the market from July to August. Autumn sowing is mostly done in Planting takes place in September and October, and harvesting takes place in March and April. (2) Sowing and raising seedlings 1. Before preparing the land, select neutral or slightly alkaline soil that has not been planted with onions and garlic vegetables for more than 3 years, with loose texture and good fertility as the bed land. The width of the bed crown is 1m. Sow and apply sufficient fertilizer. Generally, 45,000~60,000kg of manure or compost and 375kg of superphosphate are applied per hectare. The fertilizers used are evenly spread, then shallowly plowed and finely raked, and the borders are leveled for sowing. 2. Sowing: Green onion seeds have a very short lifespan, and the germination rate of old seeds every other year is greatly reduced, so it is advisable to use new annual seeds. (1) Broadcasting: First pour enough water, then spread the seeds evenly over the soil. The thickness of the soil should be about 1~1.5cm. Wait for the soil to cool and dry and flatten the border surface. (In this method, the soil moisture is sufficient, the topsoil is not compacted, and the seedlings emerge neatly). The surface can be covered with grass or arch film, and the soil should be kept moist before the seedlings are unearthed. Seedlings will emerge 15 days after sowing. After emergence, sprinkle fine soil to protect the roots. (2) Drill sowing: Open a shallow trench with a depth of 1.5~2cm at a row spacing of 15cm in the field, pour enough water, and after the soil is soaked dry, the seeds are evenly sown in the trench to cover the soil, and then the border surface is flattened and kept moist before emergence. 3. Management during the seedling stage: When the seedlings are 3 to 6 cm high, they should be thinned appropriately if they are too dense. Control watering before the seedlings emerge to the three-leaf stage to promote root development. Water and topdress at the three-leaf stage to promote the rapid growth of onion seedlings. Fertilize 2 to 3 times during the seedling stage. In addition to applying sufficient organic fertilizer, apply nitrogen fertilizer once in the early and middle stages of vigorous growth of the onion seedlings. Water after broadcasting or flush with water. Use 150kg of ammonium sulfate per hectare each time. (3) Field planting: The land for planting green onions is generally not suitable for deep cultivation. Deeply plowed soil is loose, and the back of the trench is prone to collapse and waterlogging during trenching and onion planting operations. A shallow rake is all it takes to remove weeds, and the trench can be planted. If you mainly eat scallions, dig deep trenches of 60cm per row, with a trench width of about 20cm and a trench depth of 25cm. Use 37500~45000kg of manure per hectare. Apply the manure to the bottom of the ditch, and then plow the bottom of the ditch to mix the fertilizer with the soil. Mix, then rake the bottom of the ditch. When planting, small and large seedlings should be planted openly. For small green onion seedlings, the density should be increased appropriately. The preparation of green onion seedlings is to plant seedlings as they are dug up, and they will return quickly and grow well. When planting seedlings, arrange the green onion leaves parallel to the ditch to facilitate future management. The distance between planting plants is about 6cm, and the depth should not bury the core leaves. Water thoroughly after planting. You don't need to water for the next 20 to 30 days. Pay attention to drainage in case of heavy rain to prevent root and stem rot. (4) Field management 1. Irrigation: The soil should be kept moist during the slow seedling stage of green onions. If it is not the rainy season during the seedling stage, watering should be carried out. The effective water content in the field should be maintained at about 70%. From the beginning of vigorous growth to before severe frost, top dressing, soil building, and adequate watering should be combined. Watering should be carried out 1 to 2 times after each top dressing and soil cultivation to keep the effective water content in the field at 80%. At this time, if there is drought, little rain, and insufficient watering, the growth rate and yield of green onions will be seriously affected. The period after frost to before harvest is the abundant period for onions, which still requires high soil moisture. During this period, the amount of watering should not be too large, and the soil surface should be kept dry and moist. Stop watering 7 to 10 days before harvest to facilitate harvesting and product storage and transportation. 2. Topdressing: The first topdressing of fresh manure is about 30,000kg per hectare about 20 days after planting, and then topdressing every 20 days or so, and the final topdressing is 3 to 4 times. You can also add 15~60kg of pure nitrogen by applying chemical fertilizer. Spread at the bottom of the ditch or on both sides of the green onion row. If the soil fertility is high and the base fertilizer is sufficient, the third top dressing may not be necessary. When the soil available potassium content is less than 120 mg/kg, use 225 to 300 kg of potassium sulfate per hectare or apply appropriate plant ash during the second top dressing for better results. 3. Soil cultivation: Soil cultivation of green onions has the function of softening the green onions and preventing lodging, and is an important management measure. After cultivating the soil, the original planting ditch becomes a ridge back. The soil concentration should be moderate each time, so as not to bury the base of the functional leaves.

When the green onions grow to a certain thickness, the soil should be cultivated for the second time. The soil should be cultivated after the dew has dried and the ground temperature is low. After that, the soil should be cultivated again every 15 days or so, and the soil should be cultivated 4 to 5 times. (5) Harvest When the green onion plants grow to a certain standard, fresh green onions can be harvested and supplied at any time according to market demand. The yield of green onions per plant in Panzhihua is 50~100kg, and the yield per hectare is more than 60,000kg. (6) Seed saving Green onions are hermaphrodite and cross-pollinated crops, mainly relying on insect pollination. When the air is dry, mature pollen can drift with the wind and can be pollinated by the wind at close range. According to these characteristics of green onions for flowering and pollination, the following seed saving methods need to be adopted to maintain and improve the uniformity and vitality of the variety: 1. Seed selection for adult plants. During the growth period of green onions, first select disease-free plants with the characteristics of this variety in the field. Save seeds. 2. When harvesting, select onions that are white, thick, long, solid, have short, strong and tight leaves without branches, and are free of diseases and insect pests, and plant them in the reserved planting land to survive the winter. 3. Dig the seeds with a row spacing of 50cm, apply 37500~45000kg of compost per hectare, and then plant the seeds into the trenches with a spacing of about 10cm. The concentration should be 1 inch above the surface of the green onions. Generally, watering is not done after planting to prevent rot, and watering is started only after bolting to avoid drying the soil, otherwise it will affect the yield of the seeds and the subsequent germination rate. It can be harvested when the capsule in the middle of the inflorescence has cracked and black seeds are exposed. After collecting the seeds, rub the seeds out, remove impurities, dry them thoroughly and store them for later use. (7) Prevention and control of pests and diseases 1. Downy mildew This disease damages leaves, flower moss and flower stalks, forming oval light yellow lesions. The edge of the sick band is not obvious, and white frost appears on the surface. Infected seedlings may cause the entire plant to die, and adult plants may become infected, resulting in reduced yields. The pathogen attaches to the remains of diseased plants as oospores and overwinters for primary infection, and then ascospores for reinfection. The average daily temperature is around 15°C, which is the season when the disease is prevalent. 2. Purple spot disease can occur in the seedling stage, onion growth stage and seed collection stage. Conidia infect adult leaves, leaf sheaths and flower moss, and small white spots appear, which then develop into spindle-shaped light brown to dark purple lesions, and concentric rings of black mold. The daily average temperature is 20~23℃, which is the epidemic season of the disease. Infection during the peak growth period of onion plants and the flowering stage of seed plants will have a great impact on fresh onion and seed yields. In the early stage of the onset of the above two diseases, using 80% chlorothalonil 800 times a liquid, or using a cupric ammonium preparation (kg copper sulfate, ammonium bicarbonate 0.55kg) 500 times a liquid, timely and strict spraying will have good control effects. 3. Verticillium wilt virus disease The pathogen is linear and spread by aphids. In susceptible plants, symptoms worsen as the virus proliferates. The leaves initially show short light green spots, which gradually develop into long yellow and green spots. In severe cases, the leaf surface is wrinkled, and the elongation of the sheaths of new leaves is blocked, causing each leaf to become clustered. It seriously affects the yield, quality and storage properties of green onions. There is no specific drug to control this disease. The disease can be controlled mainly through crop rotation and timely prevention and control of virus-carrying aphids. 4. Thrips are one of the main pests of green onions. When the weather is dry, there is little rain, and the temperature is high, the damage is serious. Nymphs and adults not only pierce and suck the sap of green onion leaves, but also transmit diseases through their wounds, thus causing great harm to green onion production. The whole field can be sprayed with bumethane emulsion or dichlorvos emulsion, with 3240g of the original solution per hectare, once on the 10th to 15th day. 5. Onion flies are also called leek maggots and root maggots. The larvae damage the stem disk and leaf sheath base of onion seedlings. Affected plants often die due to infection with rot or their growing points are severely damaged. Miaowa is sprayed with poison to kill the egg-laying adults. When planting onions, the infected seedlings are strictly removed. The rhizomes of the onion seedlings are soaked with 600 times dimethoate emulsion for a short time to kill the larvae that have not yet penetrated into the base of the pseudostem. Section 2 Onions Onions (Alliumcepa L.), commonly known as onions and onions, are plants of the genus Allium in the Liliaceae family. They are native to Central and Western Asia and were only introduced to my country in modern times. Due to its strong adaptability and resistance to storage and transportation, onions have a short cultivation history in my country, but their cultivation has spread throughout the north and south, and has become an important vegetable to adjust the supply of vegetables in the off-season. In recent years, it has also been processed into dehydrated vegetables for export trade. Onions are rich in nutrients, containing more protein, vitamins, especially sulfur, phosphorus, iron and other minerals. They are not only a stir-fried vegetable with high edible value, but also a good seasoning vegetable. 1. Morphological Characteristics (1) Roots Onions are the type of root system with the weakest absorptive capacity and shallowest distribution among all types of vegetables—chord-like roots. The depth of the onion root system into the soil and the horizontal expansion range are only 30~40cm. The main root layer is concentrated in the topsoil layer above 20cm. There is no main root, weak root branching and no root hairs.

The growth temperature required by the root system is lower than that of the above-ground part. After transplanting the onion seedlings, when the ground temperature of 10cm reaches an average of 5°C, the string-shaped roots will begin to grow normally. When it reaches 10~15°C, the growth will begin to accelerate. When the onion seedlings are growing, In the later stage, when the average ground temperature of 10cm exceeds 24~25℃, the root growth will slow down. (2) Stem discs, pseudostems and bulbs. Before the hot and dry season, the above-ground parts of onions wither and fat bulbs are formed underground. The bulbs store rich nutrients and water and are highly resistant to stress, making onions safe. Survive the heat, dry summers and cold winters. The bulbs are mostly spherical, with purple, yellow or green-white outer skin. In terms of morphology, bulbs are mainly composed of layers of thick leaf sheath bases. It is actually a metamorphosis of the leaves. Botanically, it should belong to the leaf structure. Each thick leaf sheath base is called a "scale" and is wrapped around the outside of the bulb. The scales are leathery and parchment-like, and have the function of keeping the internal fleshy scales from massive evaporation of water. The pseudostem is a cylindrical tissue, which is tightly wrapped by leaf sheaths. It is not a botanical stem. Its "scales" and disc-shaped "stem disk" are the real cause of onion shortening. of stem. (3) Leaves Leaves are divided into two parts: leaf body and leaf sheath. The leaf sheath forms "pseudostems" and "bulbs". The leaf body is dark green, cylindrical, hollow, and has an obvious groove on the abdomen, which is one of the morphological signs that distinguishes it from green onions in the seedling stage. The tubular leaves of onions have a small leaf area, and the surface of the leaves is covered with thick wax powder. This is the result of onions adapting to the dry air in the place of origin. This is an ecological feature of drought resistance. (4) Flowers, fruits and seeds Onions generally form commercial bulbs in the current year and bolt and bloom the next year. The number of bolts per bulb depends on the number of bulbs it contains. After bolting, there is an umbel at the top of the flower moss, with 200 to 800 flowers on it. There are 6 perianths, 6 stamens, a pistil in the center, an ovary in the upper position, and a dense gland at the base of the ovary. Cross-pollination. The fruit is a two-lobed capsule containing 6 seeds. The seeds are shield-shaped and have a triangular decorative surface. The outer skin is hard and wrinkled and black in color. The weight of 1,000 seeds is 3~4g. 3. Requirements for environmental conditions for growth and development (1) Growth and development process of onions 1. Vegetative growth phase The vegetative growth phase starts from sowing and seed germination to the maturity and harvest of commercial bulbs, which also goes through the seedling stage and leaf growth stage. and three stages of bulb expansion. ① Seedling stage: from sowing and emergence to when the seedlings are about 20cm tall, the pseudostem is 0.6~0.9cm thick, and there are 3~4 true leaves. It takes approximately 50 to 60 days to ensure full seedlings, protect the seedlings from overwintering safely, and cultivate strong seedlings of appropriate age are the center of cultivation management in this period. Excessive seedling age is an important reason for the decline in yield and quality caused by immature bolting. ②Leaf growth period: After the seedlings are planted, as the outside temperature gradually increases, the roots grow rapidly before the aboveground parts. After that, the aboveground parts gradually turn from slow growth to rapid growth, until the plant maintains 8 to 9 functional leaves. It lasts about 40 to 60 days (except for the overwintering period of seedlings). The cultivation and management of this period is to make the onions form a certain number of leaves early and promote the vigorous growth of the above-ground parts, so as to lay the material foundation for the rapid expansion of the bulbs. 2. After the onion bulbs are harvested during the dormant period, they must be dried before being stored in order to extend the supply period. This is also the period when the bulbs enter natural dormancy. Dormancy is the result of onions' long-term adaptation to adverse environmental conditions such as high temperature and drought in summer in the place of origin. The dormancy period is generally more than 60 to 70 days. For stored onions, in addition to selecting varieties with longer natural dormancy periods, the bulbs must also be prompted to enter dormancy as early as possible in the later stages of cultivation. The earlier the dormancy time is, the longer the natural dormancy period will be. During storage (under natural conditions) the bulbs will germinate. Also later. 3. Reproductive growth period: The female bulbs used for seed collection are usually planted in autumn after storage in summer and autumn. They will bolt and bloom under the sunshine in the following spring, and it will take about 8 to 10 months until the seeds mature in summer. The cultivation and management of this period should focus on the safe overwintering of the seed plants to promote strong flower moss and full seeds; reasonable top dressing and watering to avoid flower moss lodging. In addition, it is necessary to strictly avoid mixing between varieties and pay attention to seed isolation to ensure the purity of seeds. (2) Environmental conditions 1. Temperature Onion seeds and bulbs can germinate slowly at temperatures of 3 to 5°C, and germination accelerates when the temperature reaches below 12°C. The suitable growth temperature for the seedling stage is 12~20°C (robust seedlings can tolerate low temperatures of -6°C~-7°C). The optimum temperature for the leaf growth period is 18~20°C. Lower temperatures below 20°C are more conducive to the growth and development of underground roots. The growth of above-ground leaves, temperature and length of sunshine directly affect the formation of bulbs.

For this reason, when arranging the onion cultivation season, the seedling stage and leaf growth period must be placed under short daylight and lower temperatures, and the bulb expansion stage must be arranged under long daylight and higher temperatures. Bulbs have extremely strong resistance to cold and heat. After the natural dormancy is released, the temperature limit for forced dormancy is no less than 3°C and no higher than 26°C. 2. Long sunshine is the reason for the formation of onion bulbs. necessary conditions. Only under long sunlight does the base of the leaf sheath begin to thicken into fleshy scales to form a bulb. Long-day varieties must have 13.5 to 15 hours of long daylight conditions to form bulbs, while short-day varieties only need 11.5 to 13 hours of slightly longer daylight conditions to meet their requirements. 3. Moisture: Onions have shallow root systems and weak water absorption capabilities, so they require high soil moisture. Before and after onion seedlings are unearthed, their roots and leaves grow slowly, requiring the soil to be kept moist at all times. The period of peak leaf growth and bulb expansion is the period when onions require the most water. A lack of soil water will seriously affect the proliferation of bulbs. But in the later period, before the bulbs are harvested, the lower soil temperature will be conducive to the enrichment and maturity of the bulbs, and promote their entry into dormancy. Bulbs have extremely strong drought resistance and can maintain moisture in their fleshy scales for a long time under extremely dry external conditions to maintain the life activities of young shoots.