Detailed Explanation of Watermelon Planting Techniques and Management Points

The demand for watermelon in our country is very large, especially in summer. On a scorching summer day, eating a slice of watermelon can instantly cool you down and relieve the heat, and iced watermelon in summer is especially refreshing.

Watermelon planting techniques

1. Site selection and land preparation. Watermelon is drought-tolerant and afraid of waterlogging, and cannot be continuously cropped. The site should be selected as well-aerated, fertile sandy loam; generally, a field that has been continuously planted with watermelon is not chosen. Land preparation should involve deep plowing and fine working of the soil, with the bed furrows, waist furrows, and surrounding furrows connected to facilitate drainage and irrigation.  

2. Fertilizer and water management. Applying sufficient base fertilizer and reasonable topdressing is the prerequisite for high yield and high quality in watermelon. Base fertilizer accounts for about 60%—70% of the total amount. The application method is best as furrow application between rows or hole application, mainly using organic fertilizer, with 100kg of cake fertilizer and 50kg of bone meal per mu. Farmers without cake fertilizer and bone meal can use 50—80kg of ternary compound fertilizer, 2000kg of barnyard manure, and 2000—3000kg of high-quality compost. Topdressing depends on the watermelon growth stage. After watermelon is planted and survives, sufficient seedling fertilizer should be applied, that is, 20kg per mu of ternary compound fertilizer applied in furrows or holes. When there are 5—6 true leaves, apply vine-promoting fertilizer (ternary compound fertilizer) at 10—20kg. When the young fruit is set firmly (egg-sized), apply heavy fruit-swelling fertilizer and fruit-strengthening fertilizer, that is, about 1000kg of decomposed human excrement and urine or about 50kg of ternary compound fertilizer applied in furrows or holes per mu. During the watermelon growth period, in combination with pest and disease control, foliar topdressing (0.3% potassium dihydrogen phosphate + 0.3% urea solution) can be used to protect leaves and increase yield.  

Disease treatment of watermelon

1. Watermelon Fusarium wilt: This disease is mainly caused by soil-borne bacteria, and the bacteria in the soil can survive for 5—7 years. Control measures: a. Crop rotation. Carry out rotation with non-cucurbit crops for more than 3 years; b. Grafting. Rootstocks such as round gourd, long gourd, bottle gourd, and waist gourd perform relatively well, and the cutting graft method is simple and easy to carry out. Sow watermelon when the gourd sprouts and shows tips; the suitable grafting period is when the rootstock has two leaves and one heart. When grafting, first use a bamboo stick to wipe off the rootstock growth point, then use the tip of a bamboo skewer to insert a small hole vertically from the growth point (about 1cm deep), then take the watermelon seedling, close and pinch the cotyledons tightly, and use a small knife to cut the hypocotyl about 1cm below the leaves into a wedge shape, with the cut surface about 0.8cm long. After the sap finishes flowing, insert it into the small hole in the rootstock, and the grafting is complete. Finally, cover with film to retain moisture; c. Chemical control. At the early stage of disease onset or when the vine grows to 55cm, use 40% carbendazim suspension concentrate or 25.9% copper ammonium zinc complex aqueous solution (kang ku ling) and other 500—800 times liquid to irrigate the roots, once every 7—10 days, for 2—3 consecutive irrigations.  

2. Watermelon anthracnose. It is mainly caused by bacteria on the soil and seed surface, and spreads and invades through flowing water and wounds. Control measures: a. Deep furrows. High beds prevent water accumulation, and grass is spread under the fruit so that the watermelon does not directly contact the ground; b. Chemical control. At the early stage of disease onset, choose 40% carbendazim suspension or 70% chlorothalonil wettable powder or 25% tan te ling wettable powder at 600—700 times liquid for spraying, once every 7—10 days, for about 3 consecutive applications.  

Pest control of watermelon 

Watermelon pests mainly damage plants as follows: melon aphids pierce and suck leaves; American leafminer adults puncture leaves to feed and lay eggs, and larvae mine and feed on the leaf mesophyll inside the leaves; thrips rasp and suck the sap of tender shoots, tender leaves, flowers, and young melons; yellow squash beetle adults eat leaves, tender stems, floral organs, and young melons, and larvae damage the roots.  

Control measures:  

1. Plastic film mulching to avoid aphids.  

2. Chemical control. Use 10% imidacloprid wettable powder at 1500 times for spraying to control melon aphids, whiteflies, etc.; use 80% trichlorfon at 1000 times liquid to irrigate roots to control yellow squash beetle larvae and underground pests; use 73% propargite emulsifiable concentrate at 2000—3000 times to control red spiders and thrips. 20% cypermethrin emulsifiable concentrate at 2000 times liquid can also be used for spraying.

Environmental requirements for watermelon growth  

1. Temperature  

Watermelon is a heat-tolerant crop, not tolerant of low temperatures, and even more afraid of frost. It requires relatively high temperatures throughout the entire growth process. The minimum temperature required for watermelon growth is 10°C, the maximum temperature is 40°C, and the optimum temperature is 25-30°C. However, different growth stages have different temperature requirements. In the melon-producing areas of Alxa League, the temperature in June-July is relatively high, sunlight is sufficient, and rainfall is low, so watermelon yield is high and quality is good.  

2. Light  

Watermelon is a light-loving crop. During the growth period, it needs sufficient sunshine hours and relatively strong light intensity. Generally, there should be 10-12h of sunshine per day. When light is sufficient, the plants grow robustly, the stems and vines are thick, and the leaves are large. At the same time, it is also necessary to prevent too-strong sunlight in June-July from causing “sunscald.” In addition, light quality also has an obvious effect on the growth of watermelon seedlings.  

3. Moisture  

Watermelon has luxuriant leaves and vines, and the fruit is large and high in water content, so it consumes a large amount of water. On the other hand, it has a strong root system and can fully absorb water from the soil. Different growth stages of watermelon have different water requirements: the germination stage requires moist soil; the seedling stage has a relatively strong ability to adapt to drought, and appropriate drought can promote root expansion and enhance drought resistance; the vine-extending stage should appropriately increase soil moisture; around flowering, moisture should be appropriately controlled; the fruiting stage requires the most water, especially in the early and middle fruiting stages when the fruit expands rapidly, so sufficient water should be supplied in time; after the fruit reaches its final size, watering should be stopped in time to facilitate sugar accumulation. A dry climate is extremely favorable for watermelon cultivation. Watermelon dislikes dampness and fears waterlogging, so drainage and waterlogging prevention work for watermelon is particularly important.

4. Soil  

Watermelon is not strict about soil requirements and is relatively tolerant of drought and poor soil, but because the watermelon root system is aerobic, it needs sufficient soil air. The most suitable soil for watermelon is well-drained loam or sandy loam with a deep soil layer. It has good aeration, water infiltrates quickly after rainfall or irrigation, the ground temperature rises quickly in early spring, heat dissipates rapidly at night, and the temperature difference between day and night is large. Such soil can make seedlings grow robustly and allow more sugar accumulation in the fruit and good quality.  

5. Fertilizer  

Watermelon has a short growth period, grows quickly, has high yield per unit area, and requires a large amount of fertilizer. In addition, watermelon is mostly planted in sandy loam or poor sandy soil, so it is estimated that sufficient fertilizer needs to be supplied. Among these, nitrogen, phosphorus, and potassium are the most important for the normal growth and development of watermelon. Throughout the entire growth period, the absorption of nitrogen, phosphorus, and potassium by watermelon is greatest for potassium, followed by nitrogen, and least for phosphorus. During the fruit development period, some phosphorus fertilizer and potassium fertilizer should be appropriately increased, and large amounts of nitrogen fertilizer should be avoided to prevent affecting fruit quality.

Watermelon cultivation in our country is very common, and many people in rural areas plant it. However, among so many fruit growers who plant watermelon, some achieve a bumper harvest while others accomplish little. Besides being related to the hard work of the fruit growers, it is also related to a certain extent to the fruit growers' planting techniques.