Detailed Explanation of High-Yield Cultivation Techniques for Fresh-Eating Sweet Corn
Fresh-eating sweet corn has high sugar and protein content and good taste, and is deeply welcomed by people; it is a premium product on the fresh-eating corn market. However, during growth it is highly susceptible to pests and diseases, which seriously affect quality and yield. Therefore, to obtain high-quality, high-yield fresh-eating sweet corn, in addition to selecting good varieties according to local conditions, a series of measures must also be taken during production.
1. Land selection and fine land preparation. Choose a plot with convenient drainage, good ventilation, sufficient sunlight and deep soil. After deep plowing, expose it to the sun for several days, break the clods into fine pieces, level the field surface and open edge ditches.
2. Planting spacing. It varies by variety; generally 3000—3500 plants per mu. Too dense planting easily leads to barren stalks, while appropriately sparse planting gives a high double-ear rate and higher fresh ear yield. For field cultivation, single-row planting can be used, with a plant spacing of 25—30 cm and a row spacing of 75 cm. Wide-narrow row cultivation can also be
used, with narrow rows of 50 cm and wide rows of 90 cm.
3. Seed soaking and germination. Sweet corn has a high sugar content, and the seeds in the soil are easily attacked and eaten by underground pests, causing missing seedlings and gaps. Therefore, it is best to sow after germination.
Seed treatment. Select plump and vigorous seeds, first soak them in clean water for 24 hours, then soak them in a 500-fold solution of 50% carbendazim or 75% thiophanate for 2—3 hours. Remove and rinse them clean, drain, and germinate.
Germination. Place the seeds in a container lined with dry burlap, spray an appropriate amount of hot water at 40—50°C on the seed surface, cover with a wet cloth, and at a temperature of 25—28°C, the sprouts will be fully out after 24 hours. If the outside temperature is low, heating measures should be taken to promote seed germination. The sprouts should preferably just show white, and should not be too long.
4. Sowing. Striving for full seedlings with one sowing is the key to successful sweet corn cultivation. Before sowing, first treat the sowing holes with chemicals, apply sufficient base fertilizer and water thoroughly. Sow 3—4 germinated seeds per hole. Only after spraying insecticide on the seed surface can soil be covered, so that the pesticide solution can diffuse in the soil and pests such as ants cannot harm the seeds. Cover with 1-2 cm of soil, and seedlings will emerge in 3-4 days.
5. Field management. Thinning and final singling should follow the principles of early thinning, uniform retention, timely operation, removing dense and keeping sparse, and removing weak and keeping strong. Complete thinning and final singling before the 3-leaf stage. Use single-plant retention per hole or alternate single-plant and double-plant retention, ensuring a density of 3000—3500 plants per mu.
Water management. From after sowing to before the 3-leaf stage, if the soil is dry, water every day. Afterwards, water appropriately according to weather conditions. The 10 days before and 10 days after tasseling must not lack water; if there is drought, deep irrigation must be applied 2 times to ensure the water demand during the ear stage.
Fertilizer management. For base fertilizer, imported compound fertilizer is best, applied at 20-30 kg per mu, about 10 grams per hole. During corn growth, topdress 2 times. The first is seedling fertilizer at the 3-4 leaf stage, followed by intertillage and earthing up. Apply 5—10 grams of urea per hole each time, with 30-40 kg of urea topdressed per mu.
6. Strengthen pest and disease control. Timely control of pests and diseases is the key to ensuring high yield. Pest and disease control should focus on prevention, strictly preventing the occurrence and spread of pests and diseases.
Control of underground pests. Controlling underground pests is the key to ensuring a high seedling emergence rate. The main underground pests include cutworms, ants and slugs, and control is generally carried out by treating the sowing holes. For cutworms, before sowing, broadcast about 0.5 grams of 3% carbofuran granules per hole, with about 1 kg per mu. For ants, spray the seed surface with a 1000-fold solution of 40% omethoate. After the seeds are covered with soil, broadcast 0.3 grams of insecticide on the soil surface, which can effectively control slugs. Plots where vegetables were previously planted should be well managed for cutworm control, and sowing during the rainy season requires attention to slug control.
Pest and disease control during the growing period. The seedling stage is prone to damage by pests such as locusts and Spodoptera litura, while the main pests in the mid-growth stage are corn borers and aphids. For diseases, large and small leaf spot of corn and stalk rot should be the key targets. After emergence, spray insecticide 1—2 times generally, and at the jointing stage and heading stage spray a mixed solution of insecticide and fungicide once each. Under high-temperature and rainy climate conditions, pay attention to observing changes in the leaves. Once round yellow spots are found on the leaves, spray fungicide quickly. During the period when pests and diseases occur, spray once every 5—7 days, for 2—3 consecutive sprays. The agents for controlling corn pests include: 800-fold solution of 40% dimethoate or omethoate emulsifiable concentrate, or 2500-fold solution of 2.5% deltamethrin emulsifiable concentrate. The agents for controlling large and small leaf spot of corn include 50% carbendazim, or 75% thiophanate, or 800-1000-fold solution of 75% chlorothalonil wettable powder. To prevent the occurrence of stalk rot, lime powder can be broadcast during land preparation. If it occurs during the growing period, for mildly affected plants, broadcast lime powder around the roots; for severely affected plants, remove them and broadcast lime powder in the holes to strictly prevent the spread of pathogens. Never use a single pesticide alone for a long time. In combination with intertillage and fertilization, remove severely diseased leaves at the base of the plants and bury them deeply, which can effectively reduce the occurrence and damage of large and small leaf spot.
Strengthen rodent control. After corn tasseling, rodent bait can be continuously placed in the field to prevent damage by rats and ensure a bumper harvest.
To shorten the maturity period of fresh corn, 15 days after tasseling, when the silks of the female ear have turned yellow and shriveled, the tassel can be removed manually. On one hand, this can cut off the food source of aphids; on the other hand, it can reduce the nutrient consumption of the plant, accelerate the growth of the female ear, shorten the growth period and allow earlier harvest of fresh corn.