How to Improve the Low Fruit Set Rate of Winter Jujube? Practical Methods Shared

How to improve the fruit set rate of winter jujube?

1. Reasonable pruning.

Winter pruning means fine pruning of the fruiting branch groups. Remove the weak branches on the underside of the limb; fruit on such branches is small and of low commercial value. Fruit on excessively vigorous upright branches is large but the fruit set rate is low, so part of such branches should be appropriately thinned out, and those with space should be bent flat. Choose moderately vigorous branches as fruiting branches.

2. Disease and pest control.

Winter jujube is easily damaged by the green plant bug during the flowering period. During the flowering period, the green plant bug feeds on flower buds and jujube flowers, causing the flower buds to stop developing and wither and drop early, so that the jujube flowers cannot set fruit. Controlling the damage of the green plant bug before flowering is the guarantee for a high and stable yield of winter jujube. Spray 3-5 degrees Baumé lime sulfur mixture before bud break.

At the peak occurrence period of nymphs and adults, spray 6% imidacloprid 1500 times solution + 4.5% beta-cypermethrin 1200 times solution, and the control rate can reach more than 90%.

3. Strengthen fertilizer and water management.

Winter jujube has a large number of flowers, and flowering and fruiting require a large amount of nutrients, so fertilizer and water management must be strengthened. In particular, pay attention to autumn fertilization, which can ensure sufficient nutrient accumulation before the tree defoliates and avoid a low fruit set rate caused by insufficient nutrients during the flowering period.

4. Adopt flower-forming measures.

① Girdling. Girdling during the full flowering period of winter jujube can increase the fruit set rate by 10%-25%. It must be carried out when 30%-50% of the flowers are open; too early or too late will affect the girdling effect. The girdling position is on the main trunk 20 cm from the ground, and it extends upward year by year thereafter. The girdling width should not exceed 1/10 of the diameter of the main trunk. After girdling, wrap the girdling wound with paper to prevent diseases and pests.

② Spray gibberellin. Spray gibberellin during the full flowering period of winter jujube (1 gram diluted in 40-50 kg of water), which can increase the fruit set rate by 50%-70%.

Gibberellin is insoluble in water, so it must first be dissolved with alcohol or high-concentration baijiu when used. It must be sprayed when 30%-40% of the flowers are open. A second spraying can be carried out 1 week after the first spraying.

③ Spray water and spray fertilizer. When nearly 30% of the flowers are open, spray clean water or water with 0.3% urea or borax 2-3 times in the evening at an interval of 2 days, to keep the flower pistils moist, so as to facilitate pollination and improve the fruit set rate.