Detailed Explanation of Key Management Techniques for Apricot Trees in Greenhouses

1. Fertilizer and water management. After covering with plastic film, no more fertilizer is applied as a top dressing. After fruit set and during the pit-hardening stage, spray once with 0.3% urea plus 0.2% photosynthetic micro-fertilizer and 0.3% potassium dihydrogen phosphate. Install drip irrigation pipes inside the greenhouse and water reasonably according to soil moisture. Do not water excessively, to avoid excessive vigorous growth of new shoots, which can cause physiological fruit drop.

2. Training and pruning. For "Y"-shaped training, mainly retain lateral branches, appropriately thin out or utilize upward-growing branches, leave mediocre branches unpruned, cut back drooping branches, and remove overly dense branches, diseased and pest-infested branches, and dead branches.

3. Artificial pollination. Because the air humidity inside the greenhouse is high, pollen does not disperse easily, so place a box of bees inside the greenhouse for pollination or pollinate by hand.

4. Control of major diseases and pests. 10 days after flowering, spray 700-800 times carbendazim to control scab. Before bud break, apply 2-5 times methamidophos or omethoate by ring painting, or after bud break spray 4000 times imidacloprid plus 2000 times fenvalerate to control aphids and also treat almond sawfly. Before bud break, spray 50 times mineral oil emulsion plus 150 carbofuran to control scale insects.

5. Control of physical elements. (1) Light. Apricot trees are a light-loving species, so the selected greenhouse film should have good light transmittance. Laying plastic film on the ground inside the greenhouse can increase scattered light and meet the requirements of apricot trees. On cloudy days, the straw mats should also be properly uncovered to make full use of scattered light, and supplemental lighting should be appropriately provided artificially. (2) Temperature. Different growth stages require different air temperatures. In the early stage after covering the greenhouse, the temperature should be raised gradually; do not raise the temperature too quickly. Before bud break, 15-22°C during the day, not lower than 5°C at night; during the flowering stage, 15-18°C during the day, not higher than 23°C, 7-8°C at night; during the fruit development stage, not more than 27°C during the day, above 5°C at night; when the fruit is near maturity, daytime