High-yield technology of sweet corn

Today I have nothing to do, so I will tell you about the high-yield technology of sweet corn, which is very important.

1 Sweet corn variety selection and isolation

1.1 Choose the best and suitable varieties. Sweet corn is divided into three types: ordinary sweet corn, super sweet corn and enhanced sweet corn. The appropriate variety should be selected according to the production purpose. If the young and tender ears are mainly used as fruits and vegetables, super sweet corn varieties should be selected; if the main purpose is to make canned products, ordinary sweet corn varieties should be selected. In addition, attention should be paid to the combination of early, medium and late maturing varieties, and they should be put on the market one after another, so as to improve economic benefits.

1.2 Strict isolation to prevent cross-pollination Sweet corn should be isolated from ordinary corn or other types of sweet corn during planting to prevent cross-pollination. Common isolation methods include spatial isolation and temporal isolation. Spatial isolation is generally more than 400m away. If there are natural barriers such as woods and hills, the isolation distance can be shortened appropriately. If temporal isolation is used, the sowing period should differ by more than 30 days.

2 Sweet corn soil preparation

Sweet corn should not be planted continuously. Reasonable crop rotation can reduce pests and diseases, reduce weeds, and restore soil fertility.

2.1 Furrow and ridge base fertilizer: 15,000 kg of decomposed farmyard manure is applied per hectare. The width of the ridge (including the ditch) is generally about 130 cm, and two rows can be planted. The ditch depth is 20-30 cm. If the soil is acidic, lime can be applied to adjust the pH value.

2.2 Apply heavy base fertilizer and sufficient seed fertilizer. Dig a sowing furrow in the center of the bed with a distance of 66 cm and a depth of 15-16 cm. Apply 600 kg of compound fertilizer and 375 kg of superphosphate per hectare as base fertilizer in the sowing furrow, cover with 6 cm of soil, and then apply 150 kg of compound fertilizer (containing 15% each of nitrogen, phosphorus and potassium) as seed fertilizer, cover with 4-5 cm of soil and sow.

3 Sweet corn planting

3.1 The planting density should be determined according to the variety characteristics, planting season, water and fertilizer management level and the commercial requirements of the fruit ears. Generally, 52,500-60,000 plants are planted per hectare, with a row spacing of 60-65 cm and a plant spacing of 30 cm.

3.2 Timely sowing The sowing season of sweet corn should be arranged in combination with market supply time, consumption, the busy and idle season of fruit and vegetable processing plants, and the harvest period of the previous crop. The earliest sowing period can be when the temperature is stable above 12℃. If mulching is adopted, sowing can be started 7-10 days earlier, and if film seedlings are used for transplanting, sowing can be started 10-15 days earlier. The latest sowing period in autumn must ensure that the temperature during the harvest period is stable above 18℃.

3.3 Fine sowing Sweet corn, especially super sweet corn, has low starch content, thin grains, and a thousand-grain weight of only 110-180g, which is equivalent to 1/3-1/2 of ordinary corn. It has weak germination potential and poor soil-penetrating ability. It should be sown shallowly, and the sowing depth of super sweet corn is generally not more than 3cm, and that of ordinary sweet corn is not more than 4cm. The soil moisture for sowing is 60%-70% of the field water holding capacity. Sweet corn seeds are easily damaged by underground pests and rodents. Broad-spectrum insecticide 3% Furadan granules can be used to mix the seeds (add a small amount of water to make the insecticide adhere to the seeds). When sowing, slightly compact the soil in the sowing furrow according to the row spacing to form a flat and appropriately loose seed hole. Sow 2-3 seeds mixed with insecticide in each hole, and cover the seeds with 3-4cm of fine soil.

3.4 Spraying herbicides Spray herbicides on the day after sowing. Pour 750g of 50% acetochlor emulsion into 1500kg of water per hectare, stir while adding, mix thoroughly, and spray evenly on the ridge and furrow surface with a sprayer. You can also use 4500g of 40% atrazine emulsion and add 1500kg of water for spraying.

4 Field management

4.1 Small soiling At the 5-leaf stage, shallow tillage and loosening of the soil, topdressing, and small soiling should be carried out, and 150 kg of urea should be applied per hectare. Sweet corn seedlings are relatively drought-resistant, but afraid of waterlogging. Soaking overnight can kill the seedlings. In case of heavy rain, drainage should be carried out in time.

4.2 Soil cultivation The 7th to 8th leaf unfolds, which is the beginning of differentiation of male and female growth cones, also known as the trumpet stage or boot stage. Soil should be cultivated and loosened in time, topdressed with fertilizer, and soil cultivation should be carried out. 300 kg of urea and 225 kg of potassium chloride should be applied per hectare. This growth stage determines the size of the ear and the number of rows. Sufficient water, fertilizer and light can promote normal development, increase the number of grains, reduce top degradation, and increase the area of ​​functional leaves above the ear. The water requirement at this stage is more than that at the seedling stage. The appropriate soil moisture content is 70%-80% of the field water holding capacity. Irrigation and drainage should be carried out in time.

4.3 Before the tasseling, apply 300kg of urea and 112.5kg of potassium chloride per hectare, and carry out large-scale soiling to prevent lodging and suppress large weeds. Pollen will begin to shed 2-4 days after the tasseling. The female spike silk usually emerges 1-2 days after the male flower begins to shed pollen. If there is too much water or drought, high temperature, or too dense planting, silking will be delayed, affecting pollination. The milky stage is the main period for increasing grain weight. The absorption of nitrogen, phosphorus, and potassium nutrients reaches the highest value. Increasing potassium fertilizer can increase sweetness, and phosphorus deficiency will lead to bald tips. At this stage, the soil moisture content is required to reach 80% of the field water holding capacity.

4.4 Seedling removal and shoot picking Sweet corn has a low germination rate and uneven seedlings. Thinning and seedling supplementation should be done at the 3-leaf stage, leaving 1-2 plants in each hole. Seedlings should be fixed at the 5-leaf stage, leaving 1 plant in each hole. Pulling by hand can easily damage another seedling in the same hole. Scissors can be used to remove relatively weak seedlings. Under normal cultivation levels, only one ear of fresh bud is required per plant to ensure good quality. Generally, the first bud on the top is left. The best time to pick shoots is when the corn shoots to be picked have just started to spin silk. Hold the corn plant with one hand and the corn shoots with the other hand and pull them out from the side of the leaf sheath with force. Pay attention to protecting the integrity of the stems and leaves as much as possible. The picked corn shoots can be used as vegetables or sold. Sweet corn has the characteristic of tillering, and its tillering has little effect on the growth and development of the main stem, and can often form strong and full ears. Therefore, it is not necessary to remove tillers in the case of sparse planting.

4.5 Artificial pollination and emasculation Artificial pollination during the pollination period can make the grains plump. When there are continuous rainy days during the pollination period, artificial pollination should be strengthened. To reduce nutrient consumption, all male spikes can be cut off after pollination.

5. Prevent and control pests and diseases to ensure quality

Sweet corn plants are sweeter than ordinary corn and are very likely to attract pests such as corn borers, beetles, and aphids, so they should be controlled as soon as possible. While controlling pests and diseases, the quality of sweet corn should be guaranteed. Try not to use or use less chemical pesticides. It is best to use biological control methods to control corn pests. To control corn borers, the focus can be on inoculating trichogrammatid egg masses during the trumpet stage of corn. You can also use 0.5 kg of fungus powder containing 5 billion to 10 billion Beauveria bassiana per gram at the end of the heart leaf stage of sweet corn, mix it into about 5 kg of granules, and put it into the heart leaf. Both have good control effects and ensure the quality of sweet corn. Chemical control should avoid using highly toxic and high-residue pesticides. In the late growth stage (after silking), pyrethroid pesticides can be sprayed, and other high-efficiency and low-toxic insecticides can also be used for heart filling with liquid and powder application.

6. Harvest at the right time and market in time

6.1 Judgment of maturity The appropriate time for harvesting fresh ears is the end of milky maturity, because the sugar content of corn kernels is the highest about 20 days after pollination (milky maturity), when the sweetness is the highest and the quality is the best. If harvested too early, the kernels will contain too little, the sugar content is low, and the flavor is poor; if harvested too late, although the ears are large and the yield is high, the sugar in the kernels is converted into starch, the peel becomes thicker, and there is a lot of residue in the mouth, which loses the unique flavor of sweet corn. The appropriate harvesting period varies in different sweet corn planting seasons. Generally, spring and summer sowing can be 19-24 days after pollination, and autumn sowing is better 20-26 days after pollination. The growth period from sowing to harvesting is generally 75-85 days. When determining the harvesting period in the field, empirical methods such as observing the changes in the silk, pinching the tender grains with fingers, and tasting the sweetness can be used to determine whether it can be harvested. The silk of sweet corn in the appropriate harvesting period withers and turns black, the grains at the top of the ear are full, and the bracts at the top begin to become soft.

6.2 Harvesting and Packaging When harvesting, hold the stalk with your left hand and the corn cob with your right hand, and pull it hard to break it off. After the sweet corn is broken off, the base needs to be trimmed and cut evenly. When harvesting, do not expose the fresh husks to the sun for too long, otherwise the husks will lose water and turn yellow, the sweetness will decrease, and the appearance quality will be affected. It is generally better to harvest in the early morning or evening. After the sweet corn is harvested, its sugar content will gradually decrease. The sugar content of ordinary sweet corn decreases by about 1.8% per day after harvest. It should be processed in time after harvesting, preferably no more than 12 hours. It is best to put it on the market as soon as it is harvested, and the leaves should be harvested. The sugar content of super sweet corn decreases slower than that of ordinary sweet corn. The sweetness does not change much when stored indoors for 2-3 days or in the refrigerator for 7 days.