Management Techniques After Jujube Trees Lose Their Leaves

1. Increasing Fertilizer and Water

Jujube trees consume a large amount of nutrients during a year of growth and fruiting, which need to be replenished in time. Fertilize after the jujube trees lose their leaves and before the soil freezes. If no fertilizer was applied before the end of the year, it should also be applied as a supplemental dressing before sprouting in early spring.

Fertilizer can be applied by broadcasting or trenching. Broadcasting means spreading barnyard manure evenly under the tree canopy, then turning it into the soil. Trenching is divided into radial trenching and grid-shaped trenching. Young trees should use radial trenching: dig 6--8 radial trenches 20--40cm wide and 10--20cm deep, starting from 20cm from the trunk to the outer edge of the canopy, shallow inside and deep outside, narrow inside and wide outside, apply the barnyard manure into them and cover with soil. Bearing trees use grid-shaped trenching: dig trenches 30cm wide and 15--20cm deep along the rows under the canopy, with a trench spacing of 30cm, apply barnyard manure, and cover with soil and level it. The following year, dig the fertilization trenches in the direction perpendicular to the tree rows, forming a grid shape with the previous year's fertilization trenches, to increase the fertilization area and improve the fertilization effect. Jujube tree roots do not recover easily after injury, so care should be taken to protect thick roots with a diameter of 0.5cm or more when digging trenches.

The amount of fertilizer applied should be determined according to yield. Generally, for large bearing trees, with a fresh jujube yield of about 10--25kg per tree, apply 75--100kg of barnyard manure, plus 1.5--2.0kg of superphosphate. If base fertilizer is applied in spring, some nitrogen fertilizer can be mixed in. After fertilizing, water promptly, with the amount of irrigation based on watering thoroughly.

2. Turning and Digging the Management Belt

Turning and digging the jujube tree management belt can not only loosen the soil, intercept and store rain and snow, but also eliminate overwintering pests under the trees. Turn and dig once each in winter and spring, to a depth of 10--20cm.

3. Reasonable Pruning

Dense branches inside the canopy of jujube trees easily lead to low fruiting and poor quality. The canopy should be adjusted through pruning, and the following points should be achieved during pruning:

1. Cut off branches with no fruiting capacity or very low fruiting capacity, and thin out crossing branches, dense branches, overlapping branches and thin weak branches, to facilitate ventilation and light penetration. For water sprouts, the length to cut and retain can be decided according to the size of the space available. For multi-year water sprouts in large spaces with development potential, they can be trained into scaffold branches.

2. Saw off all dried and dead branches and diseased and pest-infested branches. The saw cuts should be made as close to live wood as possible, and the cuts should be smoothed and coated with blending paint, to prevent further drying, cracking and rotting.

3. For 1- and 2-year-old vegetative branches growing on scaffold branches, prune according to the size of the space, retaining 4--6 secondary branches, and train them into robust fruiting branch groups.

4. For aging scaffold branches, cut back by 1/3--1/2. The diameter of the cut at the retraction site should not exceed 5cm, and an upward-facing dormant bud or fruiting mother branch should be retained below the cut; for aging fruiting branch groups, comprehensively retract and thin them; for relatively intact branch groups, cut back by 1/2 or 1/3 to stimulate new branch growth.

5. For severely aging trees, stop the jujube fruit-setting treatment to restore the tree. During the period of stopping the treatment, measures such as renewal pruning and increased fertilizer and water should be coordinated to speed up the recovery of tree vigor.

4. Eliminating Jujube Tree Pests

1. Scrape off old jujube tree bark. Before the soil freezes, scrape off cracked bark cleanly, burn it in a concentrated manner or bury it deeply, to eliminate overwintering pest sources.

2. Thoroughly brush off the tortoise wax scale. The jujube tortoise wax scale (commonly known as tree louse) is one of the main pests of jujube trees. Because the jujube louse overwinters as fertilized females on 1- to 2-year-old branches, the favorable winter opportunity should be grasped to brush them off branch by branch.

3. When turning and digging the tree plate in winter, pay attention to picking up overwintering pupae and cocoons in the soil under the trees and destroying them.