Can you grow watermelons with your big friends in Tianzhu County, Guizhou Province in winter?
Cultivation techniques of watermelon in greenhouse
Biological characteristics of (1) watermelon
Watermelon belongs to the genus Panicum in Cucurbitaceae. Its root is the main root system, which is deeper than the soil and bears drought, but its regeneration ability is weak and it is not resistant to transplantation. The stem is a vine, and the vine grows. The leaves are unisexual and alternate, and the whole leaves are downy. Flowers axillary, solitary, dioecious, with male flowers first, and male and female flowers separated by a certain distance. The fruit is tall. The seed size varies with varieties, so its 1000-grain weight is between 20 and 80 grams.
(2) Select excellent varieties.
Watermelon cultivated in greenhouse generally chooses early and middle maturity varieties with small fruit shape (weighing about 2.5 kg), stable growth, easy fruit setting, good quality and low temperature and weak light tolerance. Such as early spring Redjade, good morning (8424), honey boy, ink boy, Tefeng, Xiaolan and so on. Its specific characteristics are shown in the first part of this book, Introduction to Excellent Watermelon Varieties of Melons and Fruits.
(3) Cultivation season
Watermelon is a short-day and warm-loving crop with strong cold resistance. Its growth and development process requires high temperature, sufficient sunshine, dry air and large temperature difference between day and night. Therefore, watermelon can be planted in Hainan all year round, but in order to meet the market demand, the best season for watermelon planting in greenhouse is from September of each year to 65438+ 10 of the following year.
(4) raising seedlings
1, seedling raising
(1) Selection of nursery
Choose a plot that is sheltered from the wind and sunny, has good drainage, has not planted melon crops in recent years, and is close to the field.
(2) Selecting seedling tray
Choose 50-hole (5× 10) or 54-hole (6×9) plastic floppy disk as seedling tray.
(3) Preparation of nutrient soil
According to local conditions, the crushed and sieved field soil, fully decomposed farm manure, plant ash (chaff ash) or coconut shells are selected and evenly mixed according to the volume ratio of 4: 3: 3, and 1kg ternary compound fertilizer (n-p-k = 15) is added per cubic meter. In order to reduce the occurrence of diseases, the culture soil should be disinfected. Method 1: Formalin is added with water to make a solution of 100 times, which is sprayed on the culture soil. The culture soil of 1 m3 needs 0.2 ~ 0.25 kg of formalin, then it is evenly stirred and piled up. Cover with plastic film and uncover for 2 ~ 3 days. After 10 ~ 14 days, it can be used after the traditional Chinese medicine gas in the soil is exhausted. This method can prevent collapse. Method 2: Dissolve 1 m3 culture soil in 80-100g water of 50% carbendazim wettable powder to make 500-600 times solution, spray it, mix it with the culture soil after spraying, cover it with a film, uncover it after 2-3 days, and use it after the medicine gas is discharged. The pH value of the cultivated soil is required to be 6 ~ 7, so as to achieve the effects of loosening, maintaining fertilizer, water and complete nutrition.
(4) seed treatment
First of all, we should choose varieties with disease resistance, high quality, high yield, storage and transportation resistance, good commodity and suitable for market demand, and the seed quality (germination rate, water content, purity, cleanliness, etc.). ) meets the requirements of seed law.
① Soak small watermelon seeds with seeds to accelerate germination.
The seedless watermelon seeds have a thick shell and a layer of mucus on the surface, so the water absorption rate is slow. Before soaking the seeds, put the seeds into a small amount of water, rub them repeatedly with fine sand to remove the mucus on the surface of the seeds, then put them into constant temperature water at 50 ~ 55 degrees Celsius, with the amount of water being 5 ~ 6 times the volume of the seeds, keep soaking the seeds for 65,438+05 minutes (while stirring), naturally cool them to about 30 degrees Celsius, and then kill them. Soak the seeds in normal temperature water for 4-6 hours, take them out and soak them in 10% trisodium phosphate solution for 20 minutes, then take them out and wash them for at least 3 times. Then wrap the seeds with wet cloth and germinate at 28 ~ 30 degrees Celsius. After about 40 hours, 70% ~ 90% can be sown when the seeds grow buds of about 0.5 cm (that is, when the buds are exposed). Each acre of greenhouse needs about 25 grams of seeds. Conditional incubator can be used to accelerate germination.
② Soak seedless watermelon seeds to accelerate germination.
The seedless watermelon with small fruit cultivated in greenhouse has small seeds, thin seed shell, strong water permeability, poor seed development, small cotyledons and less storage materials. Therefore, the technical requirements for soaking seeds and accelerating germination are strict. That is, soak the seeds in constant temperature water at 50-55 degrees Celsius for 15 minutes, then wash them with clear water, spin-dry them, put them in an incubator at 31-32 degrees Celsius to accelerate germination, rinse the secretions with clear water every 12 hours, and continue to accelerate germination after spin-drying. After about 24 ~ 48 hours, the germination rate of seeds can reach more than 85%.
(5) Sowing method
Put the prepared nutrient soil into the seedling tray, and press it while filling it, so that the cultivated soil is loosened and neatly and tightly discharged on the flat seedbed. Water the seedling tray thoroughly the day before sowing. When sowing the next day, push a white seed into the hole 1.5 ~ 2 cm, cover it with thin soil, compact it gently, and then pour a thin layer of water.
(6) Seedling management
Set up a small arch shed on the seedbed, cover it with agricultural film or sunshade net to adjust the temperature and humidity. In case of continuous low temperature weather, cover with agricultural film to keep warm. When the weather clears up, first uncover the membranes on both sides of the small arch shed for two days, and then completely uncover them; In case of hot weather, shade the sunshade net every morning from 1 1: 00 to 15: 00 in the afternoon; If the rainy weather lasts too long and the seedlings grow white, 25,000 times of paclobutrazol should be sprayed in time to prevent the seedlings from growing white. Water in the morning or at night to keep the soil moist.
Watermelon seedling diseases are mainly damping-off, in addition, anthracnose and Fusarium wilt also occur from time to time. Rhizoctonia solani can be sprayed or irrigated with 72% gram green wettable powder 1000 times. Anthracnose can be sprayed with 800 times solution of 70% thiophanate-methyl wettable powder, 1 time, once every 5 ~ 7 days, for 2 ~ 3 times.
2. Grafting and seedling raising
At present, the watermelon cultivation in greenhouse of Zhejiang Farmers' Watermelon Consortium uses seedlings, but with the continuous expansion of watermelon area and the expansion of sloping land planting, grafted seedlings must be used in the future. Grafting seedling, that is, using Fusarium wilt resistant gourd, pumpkin or watermelon rootstock as rootstock, can play a role in disease resistance, yield increase and income increase. Watermelon rootstock resistant to Fusarium wilt has strong affinity, good quality, drought resistance and high yield, and can prevent root-knot nematodes, but it is not suitable for areas with serious Fusarium wilt and frequent low temperature and rainy weather. The rootstock is zucchini, which has strong affinity and resistance to Fusarium wilt. At present, watermelon rootstocks and melons resistant to Fusarium wilt are mostly used as rootstocks.
(1) rootstock cultivation
(1) soaking seeds to accelerate germination
Wash the rootstock seeds with clean water, then soak them in constant temperature water at 55 degrees Celsius for 15 minutes, take out the gourd seeds and soak them in clean water for 10 hours, soak the watermelon rootstock seeds resistant to Fusarium wilt for 6 hours, then take them out and soak them in 10% trisodium phosphate solution for 20 minutes, then take them out and wash them for 3 times, spin them dry, and wrap them with wet cloth.
② sowing method
The sowing method is the same as watermelon seedling, and seedling management is carried out in the seedling tray. In general, the rootstock seeds are sown about 7 days earlier than the scion seeds, so that the rootstock and scion can meet at the right time, which is beneficial to the smooth grafting work.
(2) scion culture
Seeds for scions (watermelons) can be planted directly on seedbeds.
(3) Grafting method
Grafting methods mainly include top grafting method (also called splicing method), split grafting method and butt joint method. This paper mainly introduces the most commonly used jacking methods at present. It is characterized by simple operation, good wound healing and high survival rate. When grafting in the rootstock nursery, it is necessary to build a shade shed to prevent direct sunlight, which will cause the rootstock seedlings to lose water and wilt, which will affect the survival rate. At the same time, attention should be paid to moisturizing, which is conducive to the healing of grafting wounds.
① Grafting tools include: new blades, bamboo sticks (ear scoops are mostly used in Wenchang at present, that is, they are improved into special needles after polishing, which are more advanced than bamboo sticks), seedling trays and 75% alcohol (for disinfection).
② Operation method: After the rootstock seedlings are unearthed, they can be grafted before the cotyledons are unfolded (about 7 days).
A, firstly, the scion is pulled out from the seedbed, washed and put into a tray filled with clear water;
B, wiping the sterilized blade with 75% alcohol to remove the first true leaf and growth point of the rootstock, and inserting the bamboo stick obliquely downward into the hypocotyl of the rootstock at the incision with a depth of 0.7 ~ 1cm. Be careful not to use too much force, so as not to puncture the skin, and it is advisable to vaguely see the bamboo stick or finger touch;
C, immediately take out the watermelon scion seedlings, close the cotyledons with thumb and middle finger, press the index finger against the hypocotyl, and peel off the epidermis from 1 ~ 1.5 cm below the cotyledons with a blade. Turn it over and cut it obliquely again to form a wedge with the length of 0.7 ~ 1 cm;
D, quickly pull out the bamboo stick of the rootstock, and accurately insert the scion obliquely into the hole of the rootstock, so that the scion clings to the four walls of the rootstock. After grafting, the cotyledons of the scion and the rootstock should be crossed and not fixed.
(4) Grafting seedling management
Build shade shed and moisturizing arch shed. The arch shed can be built with bamboo pieces and covered with plastic film, and both sides of the film are in contact with the border and pressed. After the seedlings are grafted, they are moved into the arch shed and immediately covered with plastic film. Always check whether the surrounding film is tightly covered, and cover the shade shed to prevent direct sunlight from hitting the seedlings. The humidity in the shed should be kept above 93%. If the humidity is too low, spray water to moisturize in time. Observe the growth of melon seedlings every morning to ensure that there are water droplets on the edge of melon leaves and water mist spots on the film in the shed. In case of wilting, it can be properly drenched with water to moisturize. If the temperature in the shed is too high at noon, it should be ventilated in time, or open one side of the film, ventilate and cool down, and spray water around the melon seedlings, shed film and frame to cool down. When the temperature drops to a suitable temperature, cover the film. 2 ~ 3 days after grafting, it is generally closed, moisturized and shaded. After 3 ~ 4 days, a small amount of ventilation is started in the morning and evening when the air humidity is high, and then the ventilation volume is gradually increased, but the humidity is still high.
Seedless watermelon seedlings with small fruits have weak growth potential, strict requirements on the environment and relatively high requirements on grafting technology, mainly by controlling temperature and humidity. The humidity should be kept above 93% and the temperature should be between 25 and 30 degrees Celsius. Beyond this temperature range, grafting is difficult to succeed. Therefore, plastic sheds and sunshade nets can be used to adjust the temperature. When the temperature in Sanya is low in winter, grafting bases and plastic sheds can be built, and arch sheds can be added to keep warm. In high temperature climate, the sunshade net of the shed cover can be leveled, and the surrounding area is ventilated and sprayed with water to cool down. In addition, because seedless watermelon scions are small, the needles are required to be thinner than ordinary needles to match the grafting interface and improve the survival rate.
Grafted seedlings should be illuminated in the morning and evening after the fourth day, and then the illumination time should be gradually extended. Generally, seedlings are shaded at noon within 7 ~ 10 days and exposed after 10 days, which is the same as seedlings.
(5) standard of sound seedling
Morphological characteristics of watermelon seedlings: cotyledons and true leaves are wide and thick, leaves are dark green, hypocotyls are stout, and petioles are short and thick. At cotyledon stage, radicle is stout. Cucumber seedlings have many lateral roots and developed roots. The leaves are densely covered with many thick hairs and have a white waxy layer.
(5) Soil preparation and base fertilizer application
1, soil selection
Watermelon has wide adaptability to soil, and the most suitable soil is beach, sandy loam or loam with flat terrain, deep soil layer and convenient irrigation and drainage. The pH value of the soil should be between 5 and 7. Watermelon should avoid continuous cropping, and should be planted in paddy field without melon crops in the previous crop; Grafted seedlings are not strict with planting requirements, but perennial melon crops should not be planted on sloping fields, and paddy fields should be rotated.
2. Soil treatment
After Gua Tian is selected, 20 days before 15 ~ planting, it should be plowed and raked to a depth of about 30 cm, then basked in the sun, and then leveled with two plows and three rakes. If the pH value of the soil is acidic, 50 kilograms of quicklime can be used for soil improvement per mu.
3. Apply base fertilizer
Base fertilizer is the nutrient needed by watermelon in the whole growth period, which plays an important role in promoting root growth and maintaining plant growth. It is not a substitute for general topdressing, especially for fields with poor soil quality, more attention should be paid to the application of base fertilizer. Base fertilizer accounts for more than 70% of the total fertilization. Organic fertilizer with long fertilizer efficiency and complete nutrients is the main ingredient, supplemented by appropriate amount of inorganic fertilizer.
Before planting 15 ~ 20 days, the soil should be deeply turned and raked, and after composting 15 ~ 20 days, high-quality farm manure 1500 ~ 2000 kg, cake fertilizer 30 ~ 50 kg and calcium superphosphate 40 ~ 50 kg, ternary. For sandy soil, the amount of compound fertilizer should be reduced to prevent fertilizer damage.