Current status of longan production in Vietnam
Longan (Dimocarpus longan Lour.) is one of the main fruit trees grown in Vietnam and the concentrated growing areas are in a number of provinces in the North and Mekong River Delta provinces. According to statistic data in 2017, the area under longan cultivation of the whole country was 73.3 thousand ha and the production was estimated at 550,000 t year‑1. These respective figures were 35.6 thousand ha and 186.9 thousand t in the northern provinces and 27.8 thousand ha and 245 thousand t in the Mekong River Delta provinces. In the northern provinces, longan is grown mainly in Son La and Hung Yen provinces, accounting for more than 30% of the provinces total area of fruit tree with the main cultivars being grown: PHS2, Huong Chi and PHM99.1.1, HTM1, HTM2 and T6. Harvesting time of these cultivars fluctuates from July 10 to October 5 every year. The average yield is 5.6 t ha‑1. Intensive farming techniques have been mainly applied in specialized growing areas to give high yield at 20-22 t ha‑1. Amount of fertilizer applied to a tree year‑1 is as follows: 40-50 kg of manure + 0.5-1.0 kg of urea + 1.0-2.0 kg of superphosphate + 0.5-1.0 kg potassium chloride + corn flour or soaked soybeans. Foliar fertilizers are additionally applied at the fruit development stage. In the Mekong Delta provinces, longan is grown mainly in Tien Giang, Ben Tre, Vinh Long, Dong Thap and Soc Trang province. The cultivars being grown in the Mekong River Delta provinces include Tieu da bo, Xuong com vang, Xuong com rao, yielding at 10 t ha‑1 in average. Intensive farming techniques have been used to increase yield to 20-25 t ha‑1. The techniques of off-season flowering treatment to manipulate harvesting time have been commonly applied in the longan growing provinces in the Mekong River Delta.
Hung, N.Q., Hung, V.V., Hong, N.T.B. and Bay, D.T.B. (2020). Current status of longan production in Vietnam. Acta Hortic. 1293, 15-20
longan, 'Huong Chi', 'Tieu da bo', harvesting time spreading, Mekong River Delta