Technique of spreading the fruit harvest on Hung Yen longan trees

Basic characteristics of some longan varieties in Hung Yen

- The super sweet longan variety has the characteristics of high purity, easy to control, produces fruit in different seasons, thick fruit pulp, very sweet and is very suitable for processing because the finished product rate after processing is significantly higher than other longan varieties.

Mr. Hoang Quang Tuan in Chi Minh commune (Khoai Chau, Hung Yen) processes longan trees to produce fruit out of season, bringing in high income. Photo: Hai Tien.

- The T6 variety is very popular in the market because of its beautiful fruit appearance, thick sweet flesh, good price, easy to influence flowering and fruit setting in the off-season, but has the disadvantage of being grown in the Red River Delta, which is easy to lose fruit because it is not tolerant of heat (over 35 degrees Celsius), especially sunlight with west wind.

- T2 variety is also suitable for "catching" off-season fruit, taking main-season fruit, tough fruit pulp, not suitable for consumer tastes in the market. T1 variety in the main season, no need for technical intervention still flowers but sets very little fruit, if processed off-season the fruit will be very bad.

- Huong Chi longan is considered a "good variety" because it flowers easily, bears fruit, has a beautiful bright appearance, thin skin, 2 layers of thick flesh intertwined, sweet and fragrant, but you have to actively cut the flowers and prune the fruit to get consistent quality because in the same season the tree produces many batches of flowers and bears many batches of fruit.

- Khoai Chau late longan variety bears fruit every other year, can withstand heat very well, has large, even fruit, thick flesh, has the disadvantage of thick, brittle skin, easy to crack, bad appearance, must be cultivated intensively to ensure good quality.

- The old-fleshed longan variety has the advantage of small seeds, thick flesh, sweet and aromatic taste, slow harvest but still gives stable fruit quality.

- The rock sugar longan variety has small fruit, very small seeds (as big as peanuts or soybeans), thick flesh, sweet, very fragrant, often bears fruit every other year, difficult to "catch" fruit, low yield so it is only grown sporadically in the home gardens of some households in the Hung Yen city area.

Off-season longan still has thick, delicious, sweet flesh, no less than in the main season. Photo: Hai Tien.

Treatment for longan trees to bear fruit out of season and in between seasons

1. General requirements

It is necessary to base on the agro-biological characteristics of each longan variety mentioned above to develop a plan for spreading the fruit crop for the longan garden, in which the month in which the fruit is harvested must be taken care of in the month of the previous year so that the garden grows healthily and balanced, ensuring that before processing the longan tree must produce 3 reindeer (each reindeer is about 45 days long). At the same time, it is necessary to wait for the 3rd reindeer to turn a thick, even green color (touching it will feel that these leaves are clearly thicker than the other leaves on the tree) before proceeding sequentially according to the steps mentioned in part 3 below.

2. Pruning, fertilizing and nurturing the shoots

Cut off all low branches, diseased branches, hidden branches, weak branches and lower excess branches; apply lime water to the trunk and primary branches; collect and burn all plant residues in the garden, combine with balanced nitrogen, phosphorus and potassium fertilization.

Depending on the actual growth of the tree and the fertility of the soil, determine the appropriate amount of fertilizer. Specifically, trees from 6 to 15 years old are fertilized with 3 - 6 kg of organic microbial fertilizer, 1.2 - 2 kg of superphosphate, 0.2 - 0.5 kg of potassium chloride per tree. In which, phosphorus and organic fertilizer are applied together during the first pruning; potassium is applied when the third reindeer turns brown.

In addition, after each time the leaves turn bright green, the banana tree needs to be fertilized with fertilizers high in nitrogen. When the tree's leaves turn dark green, add superphosphate to help the leaves become thicker and healthier. At the same time, monitor and promptly prevent pests such as aphids, aphids, and downy mildew, and cut off dragon shoots and prune branches that grow densely inside the tree canopy.

Hung Yen longan has a lot of flowers this year, the possibility of a good harvest is high. Photo: Hai Tien.

3. Stimulates flower bud differentiation

In addition to applying potassium fertilizer as above, it is necessary to spray MKP when the 3rd reindeer is young, wait until the tree changes from vegetative growth to reproductive growth, then water thoroughly, wait 1-2 days for the entire tree roots to absorb water evenly, dilute Kalichlorate (KClO3) and water around the base about 50cm. After 7 days, deploy the ringing, the ring opening is 2-3mm wide, completely surrounding the base.

Depending on the actual growth of each tree, determine the appropriate dosage of KClO3 for treatment. For example, for trees with a canopy diameter of 4m, it is necessary to fertilize the roots according to the instructions above, respectively 1.5kg of superphosphate, 0.3 - 0.5kg of potassium chloride and 2kg of KClO3.

Note that after ringing the base, the longan tree is still growing well or sprouting new shoots, it is necessary to continue ringing the main trunk or first-level branches, the ring wound is not completely closed. During the period of 40 - 45 days after KClO3 treatment, absolutely do not water or fertilize the longan garden.

4. Stimulate plants to flower quickly and increase fruit set

When the longan tree sprouts flower stalks, fertilize with 0.3 - 0.5 kg NPK 13-13-13+TE/tree and water thoroughly, then water once every 1 - 2 days, until the longan tree starts to bloom, water to maintain the garden soil at 70% of the field's moisture retention capacity (stop watering when it rains) combined with spraying MKP and foliar fertilizer rich in Boron to help the tree increase its ability to set fruit, increase its resistance...

Hung Yen has many varieties of longan with good quality, and can apply techniques to produce fruit out of season. Photo: Hai Tien.

5. Longan care after fruit setting

Fertilize each tree 3 times, the first time (when the tree has just finished flowering) apply 1.0 - 1.5 kg of NPK 13-13-13 + TE combined with spraying nano silver to prevent fungal diseases on young fruit; the second time (about 25 - 35 days after the first time) apply 1.5 - 2.5 kg of NPK 13-13-13 + TE; the third time (1 month before harvest) apply 0.3 - 0.4 kg of Potassium chloride or spray foliar super potassium fertilizer twice, 5 - 7 days apart to increase fruit quality.

6. Harvesting and processing

Harvest longan on sunny days, when the fruit is just ripe, late harvest will reduce the quality of the fruit. Based on experience, harvest when the fruit skin is tight, the flesh is thick and sweet or use a Brix meter to determine the exact time of ripeness (depending on the variety).

Harvest longan according to the principle from bottom to top, from outside to inside, the first ripe bunch is picked first, the later ripe bunch is picked later. Use scissors to cut the fruit stem length to about 20cm with 2-3 compound leaves. After harvesting, immediately process, including removing cracked fruits, diseased fruits, crooked fruits, fruits smaller than normal and shortening the stem by 5cm, then arrange each bunch of fruit in baskets with sparse holes, transfer to consumption or sell to traders.

If you leave the longan overnight, you must spread the bunches of longan on a clean, soft layer of lining in a cool place, free from birds and mice.

By doing so, earlier this year, Mr. Hoang Quang Tuan in Chi Minh commune (Khoai Chau, Hung Yen) harvested 2,000 kg of off-season longan, selling to consumers for 80,000 VND/kg. In addition, a household in Khoai Chau town also made a big profit thanks to Mr. Tuan's advice on growing off-season longan. Previously, this household planned to cut down the entire longan garden because the main-season production brought too low an income.

Longan varieties all have the common characteristic of "fruiting year, branching year". This means that every 1-2 years there is a crop failure and the tree recovers its health to nourish the branches. Therefore, it is necessary to apply many technical measures such as fertilizing, tightening water, ringing branches or watering with potassium chloride to limit the phenomenon of fruiting every other year.

However, there were still years when the above techniques were applied and the longan crop was still lost on a large scale, due to "slip" treatment, the winter weather that year was unusually warm and rainy, beyond the gardeners' forecasting ability.

Source: https://nongnghiep.vn/ky-thuat-rai-vu-thu-hoach-qua-tren-cay-nhan-hung-yen-d745810.html