In recent years, the industrialization and scale of watermelons in facilities have been rapidly developed, and the planting area of ​​watermelons in greenhouses in early spring has expanded year by year. In order to raise seedlings early, plant early, improve planting efficiency, and effectively prevent frost damage and blight of early spring watermelon seedlings, technical staff of Xiajin County Vegetable Bureau of Shandong Province instructed melon farmers to adopt five-layer film covering and grafting seedling technology to enhance the low temperature tolerance of watermelon. It was listed at the beginning of the month, 10 to 15 days ahead of the four films, with an output value of 12,000 yuan per mu and a net income of 8,000 yuan.
First, the variety selection
Choose high-quality varieties that are resistant to disease, low temperature, early maturity and high yield. The varieties with good performance in production include early spring ruby ​​(small melon) and Jingxin series (medium melon).
Second, the choice of rootstock
The selected rootstock must have good affinity with watermelon. The rootstock should be highly resistant to watermelon wilt, with low temperature resistance and strong resistance to stress, and has no effect on the quality of watermelon. Such as black seed pumpkin rootstock, Japan's special selection of new soil, super pounds and so on.
The author suggests that melon farmers buy the appropriate age-appropriate seedlings in the regular nursery, or provide seeds to nurse the seedlings, so that the quality of the seedlings is guaranteed, and the second is to eliminate the cumbersome process of seedlings.
Third, colonization
Five-membrane watermelon refers to a layer of two membranes under the greenhouse film 20 cm, two membranes under the shed, and the small shed in the middle shed, the last layer is the mulch. This model watermelon is generally planted in mid-February, and can be flexibly controlled according to the weather. In principle, the 5 cm ground temperature reaches 10 °C or above. According to the characteristics of watermelon varieties, the planting density is reasonably arranged. Generally, 630-730 plants per acre are planted, the row spacing is 3 meters, and the plant spacing is 0.3-0.35 meters. Point water planting, the surface of the nursery and the surface of the seedlings are basically flat. After planting the seedlings, cover the middle arch shed and the small arch shed to facilitate the warming of the seedlings as soon as possible.
Fourth, post-plant management
1. Temperature. The minimum temperature requirement for watermelon growth period is higher than 10 °C, the highest temperature is lower than 40 °C, the suitable temperature for germination is 28 °C ~ 30 °C, the suitable temperature for seedling period is 22 °C ~ 25 °C, and the suitable temperature range for stretching vine is 25 °C. ~28 ° C, the appropriate temperature range of the period is 30 ° C ~ 35 ° C. When the shed temperature is higher than 30 °C, the wind is properly released. On sunny days, the shed film of the small arch shed can be uncovered, and then buckled in the afternoon to increase the light and nighttime heat preservation during the day. At the end of March, the small and medium-sized arch shed film was removed, and the second film was removed on May 1.
2. Water management. When planting, the planting water is poured, and the seedling water is poured according to the sensation, and the watering is controlled before the seedlings are spread. When the young melon grows to the size of the egg, it enters the period of expanding the melon, strengthens the watering, and then keeps the ground to see the wet. Usually watering once every 7 days, stop watering 7 days before harvesting, so as not to reduce the sugar content of the fruit, and reduce the cracked melon.
3. Reasonable topdressing. The absorption ratio of nitrogen, phosphorus and potassium in watermelon is roughly 3.3:1:4.3. The application of nitrogen fertilizer in the early stage promotes the growth of alfalfa, and the application of potassium fertilizer in the middle and late stages can improve the fruit quality. The planting period is 5-10 kg per mu, and the size of the young melon egg can be combined with irrigation to apply the fertilizer. The fertilizer is 10 kg per mu and the potassium sulfate is 10-15 kg. When the fruit is expanded to the size of the bowl, the per acre of sulfuric acid is applied. Potassium 15 kg.
4. Pollination. Select the second or third female flower pollination of the main vine. The pollination time is from 8 to 9 am. The male flowers that are open on the day are taken off, and the stamens are gently rubbed on the head of the female flower to make the stigma covered with pollen. In the case of insufficient light and low temperature, the male flower basically has no pollen, and the gibberellin can be used to increase the sitting rate.
5. Choose melons and melons. After 5 to 9 days of pollination of watermelon, when the melons grow to the size of the fist, they should choose melons and melons in time. Choose melons that have melons and are not pests and diseases, and only one melon per plant. When the watermelon single melon weighs 500 grams, it will give the melons the main vines in time, and the water and fertilizer will focus on the watermelon fruit.
6. Choose to keep two melons. Five days before the ripening of the head squash, pollination was started on the female flowers that had been opened. After harvesting the head and melon, strengthen the management of water and fertilizer, and promote the second melon to further improve the planting efficiency.
5. Harvest at the right time
The harvesting period of watermelon in early spring greenhouse is relatively strict. It is generally matured about 35 days after artificial pollination. The watermelon harvested at the right time is sweet, juicy, colorful, and has good flavor. The weight of single melon is up to 5000 per mu. About kilograms.
Harvesting is suitable in the morning, because the internal temperature of watermelon is low after nighttime cold, and it will not accelerate the breathing due to the high temperature inside the melon after harvesting, which will affect the quality and storage. Do not harvest within 3 days after irrigation, because there is a “return†process in the watermelon to reduce the sugar content. Keep the handle when harvesting, as a sign of fresh melon and extend the storage period. In the process of harvesting, handling, etc., it should be lightly picked to prevent the internal damage of the watermelon caused by the extrusion, so that the watermelon loses the edible value and reduces the economic income.
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