Nine matters needing attention in Longan Seedling cultivation

Longan is not only a kind of tree species with medicinal value in pulp, pericarp and root, but also has a very high ornamental value because of its small and charming flower shape, round and lovely fruit. However, the cultivation of such an effective tree needs more care from nine aspects.

Seedling selection: seedling selection is an important technical link, which requires pure variety, strong plant growth, thick green leaves, well-developed whisker roots, no diseases and insect pests, and there are more than two mature shoots above the grafting interface of grafted seedlings. The old residual seedlings with aging trunk and yellowed leaves and seedlings with too small growth should not be planted.

Planting: the size of the planting hole mainly determines the amount of organic fertilizer in the improved soil, which should not be less than 0.8 × 0.8 × 0.6 m in length × width × depth. The hole filling base fertilizer mainly includes topsoil, weeds, pond mud, garbage, pig and cow pen manure, chicken manure, which can be layered or mixed to fill the hole, which can be replanted after 1-2 months of backfilling. It can be planted in all seasons except in winter. Generally speaking, spring planting is the best. It is suitable for planting that the loose soil of the planting hole is settled and the root neck is flat on the ground or deep into the ground for 3-5 meters, so that the soil is in full contact with the root system and the root water is drenched. Watering the soil after planting keeps the soil moist. Pay attention to avoid planting seedlings in rainy days, planting muddy seedlings should not disperse the mud masses, and planting bare-root seedlings should make the roots fully extended and evenly distributed.

Fertilization: the longan tree can be fertilized one month after planting, and it is suggested that "one shoot and two fertilizers" should be implemented, that is, the first fertilizer should be applied when the shoot top bud germinates, and the second fertilizer should be applied when the new shoot elongation stops and the leaf color changes from red to green. In addition, organic manure is applied to winter fertilizer from November to December every year.

Watering: keep the soil relatively dry before flowering. From flowering to autumn shoot emergence, the soil should be kept moist, the water supply should be balanced, water should be irrigated (or drenched) in case of drought, and stagnant water should be eliminated in time in case of rain.

Pruning: longan trees are mainly pruned 1-3 years after planting, and 3-4 main branches with uniform distribution and strong growth are cultivated at the trunk height of about 30-50 m, and then the main branches extend naturally, cutting off overdense branches and branches of diseases and insect pests to form a three-dimensional fruiting crown.

Pest control: if leaf spot, anthracnose, longan planthopper, stem borer, and bugs occur during the growing period of new shoots, you can choose trichlorfon 600 times + 50% carbendazim 700 times, or dimethoate 800 times 10% topiramate 800 times, mixed spray control. In addition, longan ghost broom disease should be combined with shaping, pruning and thinning flowers and ears every year to cut off the diseased spikes and diseased shoots 10-20 meters away from the diseased part. If seedlings and newly planted orchards become sick, they should be removed in time; longan downy Phytophthora is sprayed every 15 days for 2-3 times before or after flowering. The medicament can be 0.5 Vol 0.5 100 Bordeaux solution, 70% methyl thiophanate wettable powder 1000 times solution, 25% Ruidui (Metalaxan) wettable powder 800ml 1000 times solution, 64% poison alum wettable powder 600x solution.

Flower promotion: the trunk with a diameter of about 8-10 cm was girdled before the winter shoot germinated. For the new shoots extracted after November, they should be removed manually below 10 cm of the shoot, or sprayed with ethephon solution or other shoot control agents when the shoot is below 5 cm.

Fruit protection: ring cutting or short ear cutting, delaying flowering time to avoid overcast and rainy days; spraying compound nucleotide fruit protectant at flowering stage to increase fruit setting rate and prolong flowering period; florescence to attract flies by bees, shaking flowers after rain, spraying water in dry days, artificial pollination and so on.

Harvest: it is generally better to pick in the morning or evening, not in rainy, typhoon, foggy or morning dew. To emphasize the use of the correct picking method, it is required that the whole ear should be picked, 2 compound leaves should be cut at the base of the ear 3-6 cm, and the fracture should be neat. The harvested ears should be handled carefully and dissipated heat in a cool place to preserve nutrients and prolong the shelf life.

These are the nine main points for attention in planting longan seedlings, making it easier to survive and improving the fruit-setting rate of longan trees. I believe that if longan trees are carefully preserved in these aspects, longan trees will certainly return full fruit.