The jujube tree has an extended flowering period, producing a large number of flowers that require significant nutritional resources. During this time, the differentiation of flower buds occurs simultaneously with the development of fruiting branches and fruit setting, leading to intense competition for nutrients. To ensure high yields and stable production, it's crucial to strengthen management during flowering, provide adequate nutrition, and balance vegetative growth with reproductive growth. Here are some key practices to follow:
First, apply top dressing during late May. The primary fertilizers used are nitrogen and a moderate amount of phosphate. Each tree should receive approximately 0.5 kg of urea and 0.5 kg of ammonium dihydrogen phosphate. After applying the fertilizer, water the soil thoroughly and loosen it to improve aeration and nutrient absorption.
Second, open the armor (a technique used to stimulate flowering) during the flowering period, typically in mid-June, when about 30% to 50% of the buds have opened. For young trees, start by making an opening on the trunk 20 to 30 cm above the ground. Each year, move the opening 5 to 10 cm higher. When reaching the first main branch, repeat the process. The width of the opening should be between 0.3 to 0.6 cm, adjusting based on tree strength—wider for strong trees and narrower for weak ones. On cloudy or rainy days, you can widen the opening slightly, up to 0.1 to 0.2 cm, but never more than 1 cm. After opening, protect the area by applying a diluted insecticide solution (100–200 times) every week. Cover the wound with mud to speed up healing, prevent pests, and maintain moisture. You can also use new technology like Kao 2, applying it once when 20% of the flowers bloom, then again after 30 to 35 days.
Third, perform topping on new shoots from mid-May to late June. Avoid allowing new branches to grow on the first or second branch; instead, remove the tip to control growth and conserve nutrients, which improves fruit set. Mature trees should have their heads topped to 2–6 secondary branches, with the tips removed as needed. For the base of the head, trim 3–4 secondary branches at the 5–7th node. For 1–4 secondary branches, cut at 3–5 nodes. The extent of topping depends on the tree’s vigor and available space. Weak branches should be topped more heavily, while strong branches only lightly pruned. If there is ample space, keep the pruning light. In addition to topping, remove any unnecessary shoots from the base and eliminate dense, non-productive branches to save nutrients and improve air circulation.
Fourth, spray fertilizers during the flowering stage. Mix 0.3% urea, 0.1–0.3% potassium dihydrogen phosphate, and 0.2–0.3% borax, applying the solution two to three times every half month. Spray in the early morning or evening, especially in the evening, until the leaves are damp. If it rains, reapply after the rain. Next, water sprays are applied when about 60% of the flowers are open, ideally in the evening. Use a sprayer to evenly wet the leaves. The frequency depends on drought severity—once every 3–5 days under normal conditions, and up to 3–5 times in severe drought. Lastly, spray plant growth regulators. During early flowering to full bloom, apply 15–20 mg/L gibberellin, naphthalene acetic acid, or sodium naphthyl acetate. Later, spray 30–60 mg/L of Tiaoacetic acid or 30 mg/L of 2,4-D twice, spaced 20 days apart, to reduce fruit drop.
Fifth, manage diseases and pests. Common issues include green-lipped stink bugs, nail beetles, red spiders, peach borerworms, jujube rifles, and date rust. The best time to control spider mites is just before and after wheat harvest, using 1% zinc sulfate diluted 5000 times or 15% neem oil diluted 2500 times. In mid-May and mid-June, target the second generation of green-lipped stink bugs by spraying 20% cypermethrin 2000 times or 20% chlorpyrifos 2000 times, mixed with 10% imidacloprid 3000 times. Black light traps can also help catch adults. Hang pheromone traps for peach-sucking moths in mid-June, attracting them after 5–7 days. From mid-July to mid-August, spray fungicides like Bordeaux mixture (200–240 times), 50% carbendazim WP (800 times), or 70% thiophanate-methyl WP (1000 times) alternately to prevent date rust and fruit diseases.
Sixth, place bee hives about 300 meters away from the orchard. During the beekeeping period, avoid spraying antibiotics, pyrethroids, or other harmful pesticides that could harm bees.
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