Technical Recommendations for Spring Protected Cultivation of Hami Melon
Pitaya (dragon fruit) is a perennial succulent-stemmed plant in the Cactaceae family, with a plant height of over 2 m, growing in very loose, porous, fertile sandy soil, intolerant of waterlogging, and growing well at 28°C to 38°C. I. Cuttings are most suitable in spring and summer; for cuttings, select fully developed stem segments, and the discarded branches cut off can also be used for cuttings...
Hami melon is truly a premium melon, crisp and refreshingly sweet, nutritionally rich, and with good economic returns, and its planting area is expanding year by year. However, Hami melon has relatively poor disease resistance, and is more difficult to grow than watermelon and ordinary thick-skinned melons. To ensure high and stable yields for growers and meet the demands of consumers, the following technical recommendations for high-yield, high-quality, green cultivation of spring Hami melon are provided for reference.I. Selection of Suitable Hami Melon Varieties
"Dongfangmi No. 1" is the first-choice variety for early-spring protected cultivation of Hami melon. "Dongfangmi No. 2" and "9818" can also be planted in spring, and experienced melon growers may also appropriately plant the two varieties "Xianguo" and "Xuelihong".
II. Sowing and Seedling Raising
1. Sowing period: generally sow from late January to early-to-mid February, with a seedling-raising period of about 30 days.
2. Preparation of nutrient pots and sowing. Nutrient pots use clay pots or plastic pots, with a diameter of 8-10 cm and a pot height of 8-10 cm. The nutrient soil is generally prepared from surface soil of paddy fields that have not grown Cucurbitaceae and Solanaceae crops such as watermelon and melon for many years, as well as fully composted and decomposed pig manure and cake fertilizer. Mix all materials evenly 1-2 months before use, pile them up, and sieve them for later use. Disinfect the nutrient soil 5-7 days before sowing by mixing one packet (20 g) of 30% Miaojundi into every 200-250 kg of nutrient soil; alternatively, mix 6-8 g of 50% Dexon powder into every 100 kg of nutrient soil.
3. Seed treatment and germination acceleration. Remove impurities and inferior seeds from the seeds to be sown, sun-dry them, and then carry out seed treatment. Soak the seeds in 500-600 times diluted Thiophanate-methyl or Carbendazim for 15 minutes for sterilization, then remove and wash them clean in clear water. Then soak the seeds in 55°C warm water, stirring until the temperature drops to 30°C, and let them soak for 3-4 hours. Remove, wipe off the moisture on the seed coat, wrap the seeds in layers with clean gauze, and place them at a constant temperature of 30-32°C for germination acceleration (if the quantity is small, they can be placed in a close-fitting underwear pocket). After 24-30 hours of germination acceleration, once the seeds show white, they can be sown.
4. Seedling raising and seedbed management. The nutrient pots on the seedbed should be placed tightly and at a uniform height. Electric heating wires should be laid in advance 2 to 3 days before sowing for heating, then sow one seed per pot, with the seed placed flat and the sprout foot facing downward. After sowing, promptly cover with about 1 cm of disinfected cover soil, lay a layer of plastic film flat on top to prevent water evaporation, and finally build a frame and cover with film.
Seedbed management centers on temperature control. Before emergence, keep it sealed without ventilation, and maintain the bed temperature at 30-32°C. Once 70% of the young sprouts emerge, the plastic film should be removed. If seedlings are found with their seed coats still attached (due to shallow sowing), manually remove them in the morning when the air is relatively humid and the seed shells are softer. After the young sprouts emerge, appropriately pay attention to ventilation to lower the greenhouse temperature to 20-25°C. When the true leaves of the seedlings appear, appropriately raise the greenhouse temperature to 25-28°C, and appropriately widen the day-night temperature difference to help cultivate strong seedlings. If the pot soil is too dry and needs watering, water pot by pot, and be sure not to wet the seedling leaves and cause disease. After the two true leaves of the seedlings have flattened out, the nighttime temperature of the seedbed can be gradually lowered to 12°C, and the film can be removed for ventilation to carry out hardening before transplanting.
III. Field Preparation
2.1 Field selection: choose paddy fields with high, well-drained terrain, deep soil layers, good fertility conditions, and where melons have not been grown in the past 5 years.
2.2 Apply sufficient base fertilizer. After the previous crop is harvested, promptly deep-plow and sun-dry the soil in the greenhouse, and in combination with winter soil turning, apply sufficient base fertilizer throughout the entire plow layer in one application. Apply 1500-2000 kg of decomposed organic fertilizer and 25 kg of superphosphate per mu, or 150 kg of composted cake fertilizer, 40 kg of compound fertilizer, and 25 kg of superphosphate.
2.3 Land preparation and bed making: for protected cultivation, beds should be made in a north-south orientation. In a 6 m wide greenhouse, make beds about 2.5 m wide, with a 30-40 cm wide ditch in the middle, and the bed surface shaped like a turtle back, with three ditches matching one another. The ditches outside the greenhouse should be deep so that water dries up after rain stops, in order to prevent excessively high humidity inside the greenhouse and increased disease; avoid water accumulation that causes fruit cracking.
2.4 Build the greenhouse and lay plastic film: 15-20 days before transplanting, build the greenhouse and lay the film. Lay the plastic film one week before transplanting, and the film should provide full coverage to help raise soil temperature.
IV. Transplanting
The transplanting time is generally in early March, when the seedling age is about 30 days and 3-3.5 true leaves have appeared. Planting density: about 600 plants per mu, and choose to carry out transplanting during cold-end, warm-start weather.
V. Greenhouse Management After Transplanting
1. Temperature management: after Hami melon transplanting, maintain the daytime greenhouse temperature at 27-30°C, and not lower than 20°C at night; after the seedlings have recovered, pay attention to ventilation and cooling. Before flowering, during the vegetative growth period, maintain the daytime temperature at 25-30°C and nighttime at 15-18°C; during the fruit expansion period, maintain daytime at 27-30°C and nighttime at 15-20°C; during the ripening period, daytime at 28-30°C and nighttime not lower than 15°C. During the vegetative growth period, the day-night temperature difference should be 10-13°C, and after fruit set it should be 15°C.
2. Fertilizer and water management: for soil cultivation of Hami melon, generally water an appropriate amount at transplanting to help the plants establish. During the fruit expansion period, appropriately apply fertilizer with water to promote fruit expansion, applying 10-15 kg of compound fertilizer or 10 kg of BB fertilizer per mu.
3. Pruning: generally adopt two-vine pruning, pinching the growing tip at the 4-true-leaf stage; select and retain two strong secondary vines of consistent growth, and promptly remove the rest. On nodes 9-12 of the secondary vines, select and retain 1-2 well-developed tertiary vines for fruit setting. After the fruit-setting tertiary vine sets fruit, pinch the growing tip 2 leaves after the fruit. The second batch of fruit can be set on nodes 20-22, and the secondary vines are topped at around node 25.
4. Pollination and fruit retention: artificial assisted pollination should be used to increase the fruit-setting rate. The use of hormones such as fruit-setting agents is not recommended, so as not to affect fruit shape and quality. Carry out artificial pollination from 7-9 a.m. When the young fruit grows to the size of a chicken egg, promptly thin the fruit, retaining 2 fruits per plant per batch.
5. Pest and disease control: give priority to prevention and use integrated control. Adopt measures such as high-bed cultivation and full mulching of the greenhouse floor with plastic film to control humidity inside the greenhouse and reduce disease occurrence. At the same time, check frequently, strengthen management, and when pests and diseases are found, promptly select biological and high-efficiency, low-toxicity, low-residue pesticides for control. During the growth and development of Hami melon, special attention should be paid to the occurrence of diseases such as gummy stem blight, bacterial angular leaf spot, downy mildew, and powdery mildew.
5.1 Gummy stem blight: keep the area around the stem base dry; prune strictly, and promptly apply medicine to wounds caused by human activity; inspect carefully and apply medicine promptly when gummy stem blight first begins. Control method: mix equal amounts of Daconil and Thiophanate-methyl and add an appropriate amount of water to form a paste; an appropriate amount of agricultural streptomycin can be added to it, and apply it to wounds and affected areas 2-3 times.
5.2 Fungal leaf blight: before onset or in the early stage, spray with 500-1000 times diluted 70% mancozeb; spray with 800-1000 times diluted 50% carbendazim; spray with 500-800 times diluted 50% thiram.
5.3 Control measures for bacterial angular leaf spot: in the early stage of disease, use 4000 times diluted 75% agricultural streptomycin; or use 600 times diluted 77% Kocide, avoiding high temperatures when spraying. When melon seedlings are young and small, choose agricultural streptomycin for control to prevent phytotoxicity.
5.4 Control measures for downy mildew: in the early stage of disease, choose 2000-3000 times diluted 52.5% Yikuaijing dispersible granules; or use 1500 times diluted 25% Amistar; or use 750-800 times diluted 72% Kelu; or spray with 800-1000 times diluted 72.2% Previcur, applying them in rotation 2-3 times. When humidity in the greenhouse is high, 20% Baifu smoke agent can also be used for fumigation.
5.5 Control of whiteflies: for whitefly control, treat early and treat when small. Once an infestation is found, promptly select biological and high-efficiency, low-toxicity, low-residue pesticides for control. Observe every day, identify carefully, and use the right pesticide promptly. Control method: as soon as the infestation is discovered, spray with 1500-2000 times diluted 0.5% emamectin benzoate (Lüka); or use 800-1000 times diluted 5% Tongci microemulsion (acetamiprid); or use 5000-6000 times diluted 25% Actara, etc. If disease control is also needed at this time, chlorothalonil smoke fumigant plus dichlorvos fumigation can also be used.
6. Later-stage management.
6.1 Preventing premature senescence: in the late growth stage of the plants, before the fruit stops expanding, in combination with the use of fruit-swelling fertilizer, spray a 0.3% potassium dihydrogen phosphate solution on the leaves, which helps prolong leaf photosynthetic function and improve fruit quality.
6.2 Fruit management: during the fruiting period, adopt management measures such as cushioning the fruit and turning the fruit to prevent fruit cracking and rotting, and improve the yield and quality of Hami melon.
7. Harvest at the appropriate time: fruit maturity can usually be judged by the fruit development period, the morphology of the fruit stalk tendril, and the morphology of the leaves at the fruit-setting node. Generally, the fruit development period is 40 days for "Dongfangmi No. 1", 45 days for "Xuelihong", and 55 days for "Xianguo"; when the leaves at the fruit-setting node or the fruit stalk tendril show normal scorching, it indicates that the fruit is about to mature.