Detailed Explanation of Longan Planting Techniques and Management Methods

Longan (scientific name: Dimocarpus longan  Lour.), also known as guiyuan, yizhi. Local people in Putian call it sanchi nongwei; it is an evergreen tree, usually more than 10 m tall; branchlets are stout, covered with fine pubescence, scattered with pale white lenticels. Leaves including petiole 15-30 cm long or longer; 4-5 pairs of leaflets, thinly leathery, oblong-elliptic to oblong-lanceolate, often asymmetrical on both sides; petiolules usually no more than 5 mm long.

Planting Methods

1. Longan pollination and fertilization. The main methods are: bees and artificial pollination; if it rains during the flowering period, shake the trees promptly to prevent "flower rot"; if the flowering period is dry, irrigate the soil and spray water in time to protect normal pollination and fertilization.

2. Longan flower-strengthening fertilizer: from late February to early March of this year, when flowers are 10-12 cm long, 25 kg calculated according to plant size, only 0.2 kg potassium sulfate, 0.2 kg dry rotten dilute sludge cake fertilizer. If it is a strong and vigorous tree, complete fertilizer, do not apply fat; the second time after a pure flower spike differentiation has been completed, most of the buds are full, and the flowers will no longer show the "blunt tip" danger before the flowering period (on average in late March and early April), apply mostly organic fertilizer. Based on 25 kg per plant, 1.5 kg plant fertilizer, 5 kg chicken manure, 0.4 kg potassium sulfate, 0.5 kg calcium phosphate and 0.1 kg urea.

3. Longan fruit fertilizer: from mid-May to early June, the first physiological fruit drop ends, and the second physiological fruit drop begins before fertilizing. Chemical fertilizer is spread depending on whether fruit is set. Based on 25 kg per plant, 1 kg compound fertilizer, 0.3 kg potassium sulfate, 0.3 kg urea and 0.25 kg calcium phosphate.

1. Thin out diseased spikes, weak spikes and poorly growing flower spikes, retain robustly growing flower spikes, reduce unnecessary nutrient consumption and increase the fruit-setting rate;
2. Thin more at the top of the canopy and less in the middle and lower parts, to prevent excessive fruit set at the top of the canopy from opening up the top and causing direct summer sunlight on the trunk, which weakens tree vigor;
3. Remove outer ones and retain inner ones, remove main ones and retain secondary ones, bend upper ones and retain lower ones. That is, thin out more flowers and fruit spikes on the outer periphery of the canopy and retain more flowers and fruits in the inner canopy; when there are two or more spikes on the same base branch, thin out the main flower spike and retain the secondary flower spike, or thin out the longer upper flower spike and retain the shorter, stouter lower spike.
4. In fruit thinning, fruit spikes with sparse fruit set should be thinned out, and fruit spikes with abundant and compact fruit set should be retained; however, if a single spike has too much fruit set, some side spikes should be appropriately thinned to properly reduce the fruit load per spike.