Detailed Explanation of Key Techniques for Cultivating Wild Apricot (Prunus sibirica) Seedlings

Wild apricot (Prunus sibirica) is a plant in the rose family (Rosaceae), genus Prunus. It has strong drought tolerance and cold resistance. It can be planted both as an economic tree species and as a landscaping tree for greening along streets. The fruit of wild apricot can be eaten fresh or made into preserved fruit, while the seeds (kernels) are suitable for making beverages, cosmetics, or for medicinal use.

1 Botanical Characteristics

Wild apricot is a small tree, with branchlets grayish-brown or light reddish-brown. Leaves are ovate or nearly round, with the apex long acuminate to caudate, the base rounded to nearly cordate, and the leaf margin with fine obtuse simple serrations. Flowers are white or pink, solitary; the fruit is oblate, yellow or orange-red, occasionally with a red blush; the pit is oblate, with a relatively smooth surface, broad and sharp on the ventral side, and the kernel tastes bitter. The flowering period is from late April to early May, and the fruiting period is from July to August.

2 Seedling Cultivation Techniques

2.1 Site Selection and Land Preparation

The nursery site should preferably be a sandy loam or loam soil in a leeward, sunny location with ample sunlight, good drainage, and loose, fertile texture. Low-lying land with a high groundwater table must be avoided to prevent waterlogging and frost damage. For plots sown with wild apricot, attention should be paid to the previous crop. If the previous crop was stone fruit (drupe) seedlings, it can easily cause pests and diseases, so such plots should not be selected. Land preparation is commonly carried out in two ways: autumn preparation and spring preparation. Autumn preparation can be done in mid-October, with deep plowing of more than 20 cm; spring preparation is done in April. Base fertilizer is applied at the same time as land preparation. In addition to applying 2000-4000 kg of farmyard manure per mu, 30-50 kg of potassium fertilizer should also be applied.

2.2 Sowing

Both spring sowing and autumn sowing are possible, but autumn sowing is superior to spring sowing in emergence rate and seedling growth, so large-scale seedling cultivation mainly uses autumn sowing.

2.2.1 Seed Collection From mid-July to early August, when the fruit turns from green to yellow, the seeds enter the mature stage. Select fruit with good shape, plumpness, and no pests or diseases for picking. After harvesting, pile and compost them in a cool, ventilated place for 5-7 days, then rub the seeds, use clean water to float off the seed coats and impurities, drain the water, put them in bags, and place them in a cool place for stratification treatment.

2.2.2 Autumn Sowing First make ridges, then soak the seeds in clean water for 1 day before sowing. Sow in holes, with a hole spacing of 5 cm and a sowing depth of 3 cm. The sowing rate is 20-25 kg per mu, and the target seedling density is 9000-11000 plants per mu.

2.2.3 Spring Sowing Wild apricot pits are thick, so seed treatment must be carried out before spring sowing to help increase the emergence rate. The treatment method generally uses winter sand stratification. The seed treatment time is mid-November. Choose a place with good drainage, ventilation, shade, and no rodent damage to dig a seed storage pit. At the same time, place the seeds in a 0.2% potassium permanganate solution for disinfection for 5 minutes, then rinse them clean with water, and then mix the seeds with fine river sand at a ratio of 1:3, with a humidity of 60%-70%. Spread a 20 cm thick layer of wet sand on the bottom of the pit, fill the pit with the sand-mixed seeds, and when reaching 15 cm from the ground, level the trench with wet sand, then cover it with soil mounded above the ground. Before sowing in the spring of the following year, take out the sand-stratified seeds, place them in a leeward, sunny place, cover them with plastic film, and carry out germination promotion treatment. During this period, pay attention to keeping warm and moist, and turn them over frequently. Once about 70% of the seeds have cracked open, they can be sown. The sowing method is the same as for autumn sowing.

3 Field Management

3.1 Thinning and Weeding

When the seedlings grow 3-4 true leaves, thin them, leaving 10000 plants per mu. Thinning should be combined with filling gaps, weeding, and loosening the soil. Afterward, weed 2-3 times depending on field conditions to keep the field free of weeds.

3.2 Topdressing

Wild apricot prefers potassium fertilizer. From late June to mid-July, when the seedlings enter the rapid growth period, spray 1% urea + 0.5% potassium dihydrogen phosphate on the leaves in 2 applications to promptly supplement the lack of soil nutrients and promote rapid seedling growth. After mid-July, no more topdressing should be applied to prevent excessive vegetative growth and affect lignification.

3.3 Watering and Drainage/Irrigation

Water promptly at the early stage of emergence, but use the method of small amounts and frequent applications. After the seedlings emerge completely, water according to soil drought conditions. The number of times should not be too many to prevent excessive growth, but each watering must be thorough. In hot and rainy seasons, if there is standing water, drain it promptly.

4 Pest and Disease Control

4.1 Spherical Scale Insect (Eulecanium)

Nymphs and female adults cluster on stems and leaves to suck sap, causing damaged branches to grow weakly and, in severe cases, to die. It can be controlled by spraying 50% dichlorvos emulsion at 1000-1500 times dilution plus Taoxiaoling. After the disease occurs, clean the field promptly and burn the diseased plants in a centralized manner; apply more potassium fertilizer to improve disease resistance.

4.2 Red Spider Mite

It mainly damages leaves and stems, showing dense pale small spots on the leaf surface, curling and yellowing. Damage is severe from June to July; prevention should be the main approach, with reasonable close planting. It is prone to occur under conditions of relatively high temperature, relatively high humidity, and poor ventilation. It can be controlled by spraying 40% omethoate emulsifiable concentrate at 1500 times dilution or 50% monocrotophos emulsifiable concentrate at 1500 times dilution.

4.3 Aphids

They mainly damage tender shoots. They can be controlled with 40% dimethoate at 800-1500 times dilution, spraying once every 7 days, with the number of sprayings chosen according to the severity of the pest damage.

5 Lifting Seedlings

Lift seedlings in autumn after leaf fall and before the soil freezes. Before lifting seedlings, do a good job of temporary planting, select a temporary planting site, prepare tools and packaging materials, and organize labor. When lifting seedlings, machinery should be the main method and manual labor supplementary, achieving digging, picking, grading, and temporary planting in sequence. After the seedlings are picked out, cover them with wet straw curtains, ensure all tasks are closely connected, and minimize exposure time. When grading seedlings, only those taller than 50 cm and with a ground diameter greater than 0.7 cm meet the quality requirements, and they should be tied into bundles by count and placed in storage or temporarily planted on site.