Experience of efficient cultivation of watermelon in double greenhouse

First, select improved varieties and cultivate strong seedlings in recent years, the high-quality gift watermelon varieties cultivated in coastal areas are mainly early spring Hongyu, Hongxiaoyu, Huang Xiaoyu, Texiaofeng, Xiaolan and so on, with medium fruit varieties Jingxin 1, Jingxin 2, Zaojia (8424). Melon farmers in coastal areas generally carry out seed soaking and sprouting in the first and middle of January, and raise seedlings in the greenhouse with an electric hot line (80 watts per square meter) and a light substrate in a hole tray, and pay attention to the adjustment of temperature and humidity at the seedling stage. Timely spray 75% chlorothalonil wettable powder 800 times solution + 70% methyl thiophanate wettable powder 800 times solution to prevent seedling disease caused by low temperature and high humidity in early spring. Moderate seedling refinement 5-7 days before transplanting. The seedling age was 30 days, and the planting standard was 2 leaves and 1 heart.

Second, reasonable close planting, multi-layer mulching watermelon should be cultivated in sandy loam soil which has not planted melons in 3 years and has no pollution source. Double greenhouses were built 30 days before planting, which covered no dripping film and increased the ground temperature. The width of the inner greenhouse is 4.5 meters, the width of the top film is 5 meters, the width of the skirt is 1 meter, the width of the outer greenhouse is 5 meters, the width of the top film is 6 meters, and the width of the skirt film is 1 meter; the distance between the agricultural film on the top layer of the inner and outer greenhouse is 20 cm, and the distance between the bottom and the bottom is 15 cm. The top of the greenhouse is 1.6-1.8 meters high and 50-150 meters long. Make beds in the shed 10 days before planting and spray herbicides. The width of the bed is 2 meters and the width of the middle aisle is 0.5 meters. Spray the border surface evenly with 72% du 100 ml or 96% Jin du 50 ml or 48% Zhong Ding Ling (Diletamine) 100 ml of water per mu to prevent weeds, then spread plastic film and preheat the soil. Double greenhouse + small greenhouse + plastic film mulching was used to cultivate watermelon. In the first and middle of February, the soil temperature of 10 cm underground in the greenhouse was more than 12 ℃, and when the lowest temperature was more than 8 ℃, 750 plants per mu were planted, watered with slow seedling water, sealed with planting holes, covered with plastic film, closed the greenhouse, and formed 4 film mulching. Third, apply sufficient base fertilizer, timely topdressing and pollution-free cultivation of high-quality watermelon, we should adhere to the application of mature organic fertilizer and increase the application of phosphorus and potassium fertilizer. The past strip application of base fertilizer was changed to full-layer fertilization method. Before winter, combined with digging and freezing, 1500kg / mu of rotten chicken manure and 200kg / mu of rotten cotton cake or vegetable cake were applied and turned into the bottom layer; the upper layer fertilizer was calcium superphosphate 50kg and 45% potassium sulfate compound fertilizer 50kg (potassium chloride is prohibited). After pollination of the second female flower, when the young melon began to expand, it was about 60 cm away from the melon root, and 20 kg of urea and 10 kg of potassium sulfate were applied per mu. In case of continuous drought during the expansion period, attention should be paid to proper watering or hose drip irrigation under plastic film to resist drought. After the first batch of melons were picked, 15 kg of urea + 10 kg of diammonium phosphate per mu were applied under the plastic film on the inside of the foot of the greenhouse, which was used as relay fertilizer to promote the growth of the second and third batch of melons. Fourth, scientific pruning, artificial pollination small watermelon early growth is weak, fruit shape is small, suitable to leave more vines and bear more fruit. There are usually two ways of pruning: one is to keep the main vine pruning, that is, in addition to leaving the main vine, choose to leave 2 or 3 strong vines at the base, remove the remaining son and grandson vines, and finally retain 3 or 4 pruning branches; the second is the method of coring pruning, when the main vine is 5 or 6 true leaves, keep 4 or 5 similar daughter vines growing in parallel after extraction, and the rest of the daughter vines or grandchildren are all removed. The middle fruit type watermelon adopts the method of one main and one pair of double vines. In order to improve the commodity rate and fruit setting rate of watermelon, the second female flower is usually selected for artificial pollination and marked at the same time. It is worth noting that large-scale cultivation of early spring Hongyu watermelon should be matched with flower peel watermelon varieties with similar growth period which can provide enough pollen. After the watermelon sits, you should pay attention to thinning the fruit, generally leaving 1 for each plant in the head batch.

Fifth, adjust the temperature according to the growth process and weather changes of watermelon, uncover and cover the film in time, and adjust the temperature in the greenhouse. 5-7 days after planting, keep the daily temperature 28 ℃ and night temperature 16 ℃; keep the daily temperature 26 ℃ in the vegetative growth stage and 30 ℃ in the flowering and fruiting stage; the minimum temperature in fruit development and ripening stage is 20 ℃, the highest is no more than 35 ℃. It should be noted that when the external temperature is more than 25 ℃, the apron membrane can be removed, but the greenhouse top film should not be removed to avoid watermelon cracking caused by continuous rainy weather. Sixth, select disease-resistant varieties for disease prevention and pest control, pay attention to crop rotation or grafting to change roots, and timely apply 50% carbendazim wettable powder 800 times solution or 65% more than 100 wettable powder 500 times solution or 12.5% Zhiweiling 200 times solution for root irrigation, it can effectively prevent Fusarium wilt. During the period of melon formation, especially when there is continuous overcast and rainy weather in April, watermelons should be fumigated with 45% chlorothalonil smoke agent or 250 grams of 15% tofu smoke agent per mu to control Sclerotinia sclerotiorum and Botrytis cinerea; spray 800 times liquid of 75% chlorothalonil wettable powder + 800 times liquid of 70% methyl thiophanate wettable powder to control blight and anthracnose. Once the harm of aphids and Bemisia Tabaci is found, spray 70% precious (imidacloprid) wettable powder 5000 times + 0.5% mites (avermectin) EC 1000 times. The first batch of watermelons matured 32-35 days after pollination and the second batch of melons matured about 25 days after pollination. After the watermelon is picked, it should be graded, branded, bagged, packaged and listed on the market.