Key Technical Points for Post-Harvest Autumn and Winter Management of Winter Jujube
Post-harvest technical management of winter jujube is often easily overlooked by jujube growers. During this period, although the vegetative growth of the tree is gradually ceasing, the photosynthesis of the leaves continues, and the photosynthates are continuously transported to the roots, branches, trunk and other organs for storage, accumulating nutrients for the tree and enhancing its cold resistance.
Therefore, the management of winter jujube trees after harvest occupies an important position in their annual management. Doing a good job of cultivation management during this period can lay the foundation for high yield and quality in the coming year, achieving twice the result with half the effort.
????1. Soil, Fertilizer and Water Management
Deep Plowing and Soil Improvement
Deep plowing of the soil after harvest can improve the soil's physical and chemical structure, encourage the tree roots to spread and grow deep, and enhance vigorous tree growth. It can also plow the residual branches, diseased leaves, residual fruits, weeds and other materials under the trees in the orchard into the soil as fertilizer. Deep plowing of the jujube orchard can generally be carried out in combination with autumn application of base fertilizer, with a plowing depth of 20-25 cm being appropriate.
Autumn Application of Base Fertilizer
Fertilizer should be applied promptly after the autumn harvest. The base fertilizer should be mainly organic fertilizer, and at the same time an appropriate amount of quick-acting chemical fertilizer, especially phosphate fertilizer, should be supplemented according to the soil fertility conditions. Fertilization can be carried out simultaneously with plowing and turning, maximizing the contact surface between fertilizer and root system to prevent fertilizer from being too concentrated, which can lead to poor absorption or root burning.
As for the fertilization method, it can be combined with plowing and turning for broadcast application, or applied in ring-shaped trenches, or in radial trenches. A ring-shaped trench 40 cm deep and 60 cm wide can be dug around the outer edge of the tree canopy, and the base fertilizer and compound granular fertilizer can be mixed evenly and applied into the trench, then covered with soil.
For mature large trees, apply about 50 kg of base fertilizer and 1 kg of compound fertilizer per tree; for small trees under 10 years old, apply 25 kg of base fertilizer and 0.5 kg of compound fertilizer per tree.
Irrigation and Moisture Conservation
After fertilization, water thoroughly in a timely manner, and after irrigation, hoe the soil to conserve moisture, ensuring safe overwintering.
????2. Autumn and Winter Orchard Cleaning
Pruning Diseased and Pest-Infested Branches
The overwintering sites of pests and diseases are mainly in diseased and pest-infested branches and rough bark cracks on the trees. Therefore, timely pruning of diseased and dead branches on the trees, scraping off old peeling bark, picking up fallen and rotten fruits on the ground, and clearing weeds on the ground should be carried out. These should be centralized and burned or deeply buried to eliminate overwintering eggs of green plant bugs, red spiders and other pests, as well as overwintering pathogens such as jujube rust and rot disease remaining in dead branches and fallen leaves.
Insecticidal and Fungicidal Treatment
Pests and diseases easily overwinter in ground weeds, fallen leaves, fallen fruits and shallow surface soil. Therefore, after the winter jujube trees shed their leaves, in addition to spraying the entire tree with lime sulfur mixture, fungicides should also be sprayed on the ground beneath the trees. When spraying, spray together on the ground around the trees, weeds and shelterbelts. Through insecticidal and fungicidal treatment, further reduce the pest and disease base. Since the trees have already shed their leaves during autumn and winter, pesticide application is unlikely to cause phytotoxicity, so the concentration of pesticides can be appropriately increased at this time.
Whitewashing Tree Trunks or Tying Grass
After the jujube trees shed their leaves, whitewash the trunk and the base of large branches. While serving a cold-proof function, it can also simultaneously control pests such as tortoise wax scale insects overwintering in the trunk. Next spring, remove the grass bundles and burn them, which can eliminate a large number of overwintering pests and eggs parasitic in the grass bundles.
????3. Training and Pruning
Through training and pruning, cultivate and adjust the tree structure, achieve rational layout, and improve light conditions. For overly dense branch groups as well as crossing branches and overlapping branches, all should be thinned out to maintain ventilation and light penetration within the canopy; for aging branch groups and water sprouts, heavy cutting or retraction from the base of the main branch can be carried out to promote the sprouting of new branches. Autumn and winter is an effective period for cultivating winter jujube tree vigor, accumulating nutrients, and scientifically controlling pests and diseases.
Through a series of autumn and winter management techniques including deep plowing and soil improvement, autumn application of base fertilizer, irrigation and moisture conservation, autumn and winter orchard cleaning, and training and pruning, a solid foundation is laid for high yield and quality of winter jujube in the coming year.