The price is 4-5 times higher than the peak season longan

Given the pressure to grow longan, it often comes across the rule “A good season, a bad harvest”. In recent years, fruit and vegetable research institute has developed on the basis of research achievements of longan trees to produce fruit and vegetables In Son La, Dak Lak provinces, many growers in Hung Yen have used the product potassium chlorate (KCL03) to produce longan for off-season flowering and fruiting, greatly increasing the value of longan.

According to initial results, longan trees grown in Hung Yen after treatment with potassium chlorate can bloom in late autumn and early winter and fruit around the Thanh Minh period (5 tea can be harvested from the end of March at the earliest, the latest tea will be at the end of April – Harvested at the beginning of May (solar calendar).

Ms. Luong Thi Lan (Hung Dao Township, Tien Lu) was treated with potassium chloride from the middle of the 7th lunar month (in 2022) for 12 Huong Chi Longans (6 years old), after 45 days these trees flowered and bore fruit., with an expected yield of around 700 kg, is to be harvested on the anniversary of Hung King’s death (March 10 of the lunar calendar). The selling price depends on the market at that time, but certainly not less than VND 30,000/kg, three times higher than the price of the main harvest in August every year. Ms. Lan said the price is because at the above harvest season, oranges, grapefruit, lychee and mangoes were not harvested in the north, longan fruits avoid competitive pressure.

Mr. Duong Van Tinh in Hiep Cuong Township (Kim Dong, Hung Yen) also tested potash chlorate with trade name KC – MR200 on 3 roots of Huong Chi Longan (8 years old) and is expected to harvest about 200 kg of fruit, the harvest point is around the holidays April 30th and May 1st around.

When longan managed to flower and bear fruit in the off-season, Mr. Tinh learned from his experience: the season in which potassium chlorate is used to stimulate the flowering of longan huong chi is highly effective, so it starts between April 15 and April 15 .and July 30 the lunar calendar. When processed later, the longan harvests the same crop as the early-ripening U-hybrid lychee crop, which lowers the selling price and reduces investment efficiency. Early treatment (before July 15), longan fruit development is easy to face cold weather, dry weather will fall, crop loss.

According to Mr. Dang Van Ung, head of Hiep Cuong Longan Cooperative Group (Kim Dong District), the group has 5 households to process longan for off-season flowering and harvest towards the end of the third lunar month. “If this year doesn’t jump into February, the off-season longan harvest will be delayed by about a month,” noted Mr. Ung.

In Phu Cu District, Mr. Pham Hong Ke, a member of the VietGAP Nguyen Hoa Longan Cooperative, said the cooperative owns about 7 tons of off-season longan. In which on Feb. 1 (profitably) harvested over 1 ton of fruit exported to Hai Phong at VND 50,000/kg, five times higher than the price of longan harvested in the previous year’s crop. The remaining production (about 6 tons) will be harvested from the end of April to the middle of next month (March 15 of the lunar calendar). At the same time, Minh Tan Township (Phu Cu District) also had longan for harvesting about 2-3 tons of fruit.

Breakthrough in Hung Yen Longan cultivation technique

Besides using potassium chlorate to treat off-season flowering Huong Chi Longan, some gardeners in the VietGAP Nguyen Hoa Longan cooperative also use KCLO3 in combination with traditional manual methods (circling the bark, tightening branches). Season flowering and fruiting. Like the T6 longan, the fruit is very tasty, but it is difficult to “catch” the fruit even in the peak season. Therefore, the successful treatment of the off-season flowering and fruiting T6 longan is considered a turning point in Hung Yen’s technical longan intensive farming.

According to Mr. Ke, the T6 Longan variety is difficult to “catch” but has very good resilience, the fruit is less likely to fall off in cold and dry weather compared to Huong Chi, so they are less likely to harvest outside of the season loses .

Mr. Nguyen Binh Phuong (off-season longan garden owner) in Hung Dao Township (Tien Lu District) explained that the successful treatment of longan trees for flowering and off-season harvest by some households has opened up opportunities to help the producers. The garden can “live well” due to the intensive cultivation of this culture, repelling all kinds of Thai longans imported to our country, reducing the pressure of fruit production in the main harvest, and thoroughly overcoming the biennial longan fruiting phenomenon .

Besides, there are also some farmers who have failed to use potassium chlorate to treat longan flowers off-season, and look forward to the professional level to jointly develop the planting technique with Fruit and Vegetable Research Institute soon off-season Seasonally blooming and fruitful longan trees with each specific cultivar or group of cultivars, so gardeners can soon have a “manual” to propagate the longan crop with greater efficiency.

associate Prof. Dr. Nguyen Quoc Hung, director of the Vegetable and Fruit Research Institute, said the institute is developing a process to manage off-season flowering/spreading for the Son La Longan area. In the Hung Yen area, people need to be very careful when using potassium chlorate to treat longan flowers, because each ecological region and each longan variety has different technical requirements and different processing times. The care process for longan trees after treatment is also different.

There are many manufacturers in the market who package potassium chlorate supplements according to different concentrations, ratios, dosages and trade names, farmers need to choose the right kind of potassium chlorate product with suitable quality, manufacturer-approved and supplied by reputable manufacturers. Avoid buying counterfeit goods, counterfeit goods and poor quality goods, which will adversely affect the flowering longan treatment results.

In the immediate future, in longan orchards after the off-season fruit harvest, in addition to pruning and pest control, there is a need to increase the application of macronutrients, organic and microbial organic fertilizers to restore soil fertility.