Detailed Explanation of Key Management Techniques Before and After Jujube Orchard Harvest

I. Care and Management Before Harvest

1. Preventing fruit drop. When jujube trees enter the ripening stage and up to the pre-harvest period, strong winds and heavy rain often cause fruit drop. Therefore, for jujube trees bearing many fruits, support poles should be set up for stabilization, and measures such as pulling and propping branches should be used to strengthen tree stability and reduce fruit drop caused by strong winds.

2. Adjusting unbalanced crowns. For jujube trees with unbalanced crowns where branches are lacking or there is space, inner-canopy branches and water sprouts can be pulled outward to fill the space, thereby adjusting the unbalanced crown and expanding the fruiting area.

3. Shallow hoeing to conserve soil moisture. Before harvest, for jujube orchard plots where soil moisture is particularly poor, one timely watering is still needed.

4. Disease and pest control. Before harvest, the main diseases that jujube trees are prone to include ring rot, soft rot, black spot, and fruit shrinkage disease. For jujube orchards where disease has occurred, diseased fruits on the trees should be removed early, fallen mummified fruits should be picked up, and diseased leaves and fallen leaves on the ground should be swept up to reduce opportunities for mutual infection by pathogens, and a spray of 70% fosetyl-aluminum-manganese-zinc at 800 times dilution or jingjunmeisu at 1200 times dilution should be applied for control. From fruit coloring to the mature harvest period, grass bundles should be tied at the main trunk fork of jujube trees to trap the last-generation larvae of the jujube leaf roller; the following year, from fruit coloring to the mature harvest period, the grass bundles should be removed before adult emergence and burned in a centralized manner to reduce pest sources.

5. Timely harvest. To ensure the flavor and commercial value of jujubes, timely harvest must be carried out. When picking jujube fruits, pick and place them gently to reduce wounds, so as to avoid mold and rot caused by pathogen invasion. For jujubes intended for storage and fresh-keeping, harvest may be appropriately advanced, picking from the late white-ripe stage to when about 1/3 of the whole jujube has turned red.

II. Care and Management After Harvest

1. Foliar fertilizer spraying. After jujube harvest, immediately spray the leaves with a mixture of 0.3%-0.5% urea and 0.4%-0.5% monopotassium phosphate to supplement insufficient nutrients after fruit harvest, avoid premature leaf drop, improve later photosynthetic efficiency, increase nutrient accumulation in the tree, and promote flower bud differentiation.

2. Heavy application of basal fertilizer. Basal fertilizer can be applied from after jujube fruit harvest until before leaf drop, but it is usually best to apply it in mid-October. Generally, for large trees from the growth and fruiting stage to the full fruiting stage, apply 50-80 kg of organic fertilizer per tree, mixed with 0.3-0.5 kg of urea and 1.0-1.5 kg of superphosphate. Basal fertilizer application should preferably be combined with soil plowing in the jujube orchard and digging around the tree base.

3. Plowing and soil improvement. Plowing the orchard before the soil freezes can not only improve soil structure and promote root growth, but also plow fallen leaves, residual fruits, and weeds on the ground into the soil, and turn overwintering pests in the soil, such as the peach fruit borer, jujube leaf roller, and jujube looper, to the surface to be eaten by birds or killed by freezing. In jujube forests practicing jujube-grain intercropping, deep plowing should be carried out between tree spacings and under the tree canopy; where jujube-grain intercropping is not practiced, the entire orchard should be plowed. The suitable plowing depth is 15-25 cm; the closer to the trunk, the shallower the plowing should be, and the farther from the trunk, the deeper the plowing.

4. Disease and pest control. After leaf drop, spray once with 3-5 degrees Baume lime sulfur mixture plus 200 times dilution sodium pentachlorophenate, which can eliminate some overwintering pathogens and pests.