Detailed Explanation of High-Yield and High-Quality Cultivation Techniques for Kernel Apricots

I. Orchard Site Selection. Kernel apricot trees can grow and bear fruit in areas with an altitude of 100-1800 m, a frost-free period of 100-220 days, an extreme minimum temperature below -34.7°C, an extreme maximum temperature above 43.3°C, and annual rainfall ≥35 mm (referring to conditions without irrigation). However, because apricot trees bloom early, planting is generally not suitable in areas where frost damage occurs frequently and severely during the flowering period. The orchard site should be selected in areas with no pollution of soil, air, or water. It requires a soil layer thickness of more than 50 cm, soil organic matter content above 0.7%, pH 6-8.5, groundwater level below 15 m, groundwater salt content not exceeding 0.2%, and well-drained loam, sandy loam, or light clay loam. Avoid establishing orchards in low-lying areas, windward openings, or valley bottoms in the middle-lower slopes where cold air easily accumulates.

II. Variety Selection and Pollinator Tree Configuration. For the main cultivar, select high-quality, high-yielding, commercially valuable, and highly adaptable varieties such as Longwangmao. For pollinator varieties, select Baiyubian, Yiwofeng, Youyi, etc. The same apricot orchard should have two or more pollinator varieties for mixed pollination. The ratio of pollinator varieties to main cultivars is 1:4-5.

III. Cultivation Techniques

1. Planting. (1) Planting time: From after the soil thaws in spring to before bud break; in arid and water-deficient areas, from leaf fall in autumn to before the soil freezes. (2) Planting density: Generally, row spacing of 4 m and plant spacing of 1.5-2 m are used, with 83-111 trees planted per mu. (3) Digging planting holes: On the basis of land preparation, dig planting holes 50 cm square. Apply 20 kg of decomposed organic fertilizer and 1 kg of superphosphate per hole, mix evenly with topsoil and apply, then water to settle. (4) Seedling selection and treatment: Select high-quality strong seedlings, remove the plastic strip at the graft union, cut the wounds on the main and lateral roots to fresh tissue, soak the seedling roots in clean water for 12-14 hours the day before planting, and soak the roots in 100 mg/L ABT solution for 2 hours, then dip in mud slurry. (5) Planting: Dig a corresponding small planting hole according to the size of the seedling roots, place the seedling roots in the hole, with the graft union facing the windward direction, and keep the original soil mark below the graft union level with the ground. Bury the roots in layers; when half the soil is filled, lift the seedling slightly upward to spread the roots. Pour 15-30 kg of water into the hole so that the water contacts the subsoil moisture. After the water infiltrates, fill with soil until level with the ground, level the tree basin, and never plant too deep. (6) Mulching to preserve moisture: After leveling the tree basin, immediately cover the entire hole surface with plastic film, press the edges firmly with soil, and build a small soil mound near the seedling with soil; before the rainy season begins, level the soil mound. (7) Trunk heading: Where irrigation is available, head the trunk at a height of 50-60 cm; where irrigation is difficult, head the trunk at about 40 cm. (8) Plastic tube covering: After trunk heading, cover the seedling from the upper end with a plastic tube 30 cm long and 4-5 cm in diameter, tied tightly at the top, bottom, and middle. When buds sprout, puncture holes for ventilation, then gradually cut openings and remove the plastic tube. (9) Autumn planting in dry areas: Select seedlings headed at 30 cm and plant as above. Build a soil mound around the seedling stem that exceeds the top of the stem by 15 cm, and keep the stem upright and unbent. In the spring of the second year, do not remove the cold-protection soil, allowing the stem, branches, and buds to emerge from the soil mound; before the rainy season begins, remove the soil mound in stages. (10) Replanting: When establishing the orchard, plant an additional 15% of seedlings within the planting rows in advance to facilitate on-site transplanting for replanting and make the orchard uniform.

2. Fertilizer and Water Management. Kernel apricots prefer potassium fertilizer, and the suitable ratio of nitrogen, phosphorus, and potassium is 6.3-8.1:1:8.7-10.2. Soils in China's Loess Plateau and northwestern regions are rich in potassium, but soils in Northeast China, eastern North China, Shandong, Henan, and other places are deficient in potassium and require additional potassium fertilizer such as potassium sulfate. On the basis of applying sufficient basal fertilizer, young orchards should be topdressed with about 750 kg of urea per hectare in May-June, and about 900 kg of fruit-tree-specific compound fertilizer in September-October. In mature apricot orchards, basal fertilizer should be applied early in autumn, mainly high-quality organic fertilizer, with about 75,000 kg of high-quality manure applied per hectare. Before bud break, during the pit-hardening stage, and after fruit harvest, topdress respectively with urea, fruit-tree-specific compound fertilizer, diammonium phosphate, potassium sulfate compound fertilizer, etc. During the growing season, add 0.3% urea and 0.3% potassium dihydrogen phosphate as appropriate when spraying pesticides. Generally, irrigation is carried out in combination with fertilization before bud break, during the fruit-setting period after flowering, half a month before harvest, and before the soil freezes. In water-deficient areas, water-saving measures such as flow irrigation, micro-sprinkler irrigation, or seepage irrigation can be used.

3. Flowering Period Management. To avoid late frost damage, irrigation can be carried out about 10 days before flowering, which can lower soil temperature, increase air humidity, and delay the flowering period. According to weather forecasts, when frost comes, smoke can be used to prevent freezing. Artificial pollination or bee pollination can be carried out during the flowering period. Generally, one box of @#@255@#@ or 60-80 horned mason bees is placed per mu of apricot orchard. Spraying 0.3% urea + 0.3% borax during the flowering period can promote pollen adhesion and germination and increase the fruit-setting rate.

4. Training and Pruning. Principles of training and pruning: Adopt a low-trunk, low-canopy tree shape, minimize the number and order of scaffold branches, reduce the canopy structure, make full use of space, increase the number of fruiting branches, maximize light interception, and carry the maximum yield. For young trees, the goal is light pruning and long shoots, opening the branch angles, ventilation and light penetration, rapid canopy formation and rapid increase in branch number, early fruiting, and rapid high yield. For fruiting trees, special attention should be paid to adjusting the ratio of branches to fruit and leaves to fruit, alternate bearing and renewal, preventing bareness in the middle and lower parts of scaffold branches, and ensuring stable yield and high quality.

5. Pest and Disease Control. Pest and disease control during the dormant period of apricot trees is crucial:

(1) For some diseased and insect-damaged branches, such as branches affected by apricot scab and branches damaged by tent caterpillars, they can be removed during winter pruning. (2) For scale insects such as globose scale and mulberry white scale, because they mainly overwinter in cracks on the trunk and main branches and on some branches, a brush can be used to brush back and forth on the trunk, main branches, and branches to eliminate them. (3) Apricot weevil and apricot seed wasp eggs mostly overwinter on fallen fruit, dried pits, and branches. They can be controlled by cleaning up fallen fruit, fruit pits, and dead branches in the orchard and burning them centrally. (4) Apricot star caterpillar overwinters as young larvae spinning cocoons in bark cracks. In early spring, a knife can be used to scrape off the brown curled bark on the outside of the trunk, main branches, and other trunk and branch parts, and the bark should be collected and burned. (5) Spraying 3-5°Be lime sulfur before apricot bud break can significantly reduce the base population of various pests and diseases. For various pests and diseases occurring during the growing season, targeted chemical control can be carried out.