Detailed Explanation of Key Techniques for Tianshan Spruce Seedling Cultivation

I. Seedbed Land Preparation

For spruce seedling cultivation, loam and sandy loam soils with good drainage and irrigation conditions should be selected. Spruce seeds are small, so only through intensive and meticulous cultivation can the seedling germination rate be improved and high-quality strong seedlings be produced. In autumn, deep plow the land to a depth of 250.30 cm; apply 3 tons of base fertilizer per 667 sq m. Carry out soil disinfection together with land preparation, using a 0.1% carbendazim or thiophanate-methyl solution, spraying 1 kg of solution per 667 sq m. In spring, harrow finely and make beds, striving for fine, crumbly soil, and irrigate thoroughly 3 days before sowing.

II. Seed Selection

Before sowing, winnow the seeds and select them in water. After two rounds of selection, the seed purity should be above 80%. About 5 days before sowing, soak the seeds in a 0.5% ferrous sulfate solution for 3-4 hours; when the seed shells turn iron-black, remove them and place them in warm water at 25-30 degrees C to soak for 24 hours, then remove them and place them in a wooden box, spraying them 5 times daily with warm water at 30 degrees C to keep them warm and moist. After 4 days, when more than 80% of the seeds have split open, they can be mixed with fine sand and sown.

III. Sowing Time

At our nursery, autumn frosts come early, so spring sowing is suitable. In spring, as the ground temperature gradually rises, sowing is generally done in mid-May. The sowing rate is 40 kg per 667 sq m, using wide-row drilling, with a row spacing and sowing width of 10 x 20 cm. Rake the bed surface flat, place the seeder on the bed surface, spread the seeds evenly, then cover with a layer of disinfected mixed sawdust soil (1 part sawdust, 3 parts soil), 0.5-1 cm thick. After covering with soil, press down gently, then cover well with bamboo blinds.

IV. Seedling Management

1. Shading

Tianshan spruce is a shade-tolerant tree species, especially at the seedling stage, requiring certain shaded conditions, so the method of building a frame for shade is used. After all spruce seedlings have emerged, the bamboo blinds can be rolled up from 6 p.m. each day until 9 a.m. the next day. On August 30, remove all bamboo blinds to promote seedling growth and lignification.

2. Weeding

In order to reduce heavy evaporation of soil moisture, loosen the topsoil, and increase soil aeration, the seedbed should be kept free of weeds.

3. Pest and Disease Control

After large numbers of seedlings have emerged, spray 1% carbendazim and thiophanate-methyl, with a dosage of 60 kg per 667 sq m. Thereafter, spray once every 7-8 days, for a total of 4 sprayings.

4. Irrigation

According to weather and soil conditions, water at the right time and in the right amount with a watering can to keep the soil moist.

5. Overwintering

Spruce seedlings are tender, low in lignification, and weak in cold resistance, and are prone to frost damage, especially frost damage and physiological drought in early spring, which often causes large numbers of seedlings to die. Therefore, before winter snow accumulates, effective measures must be taken to do a good job of overwintering and frost protection. Before the soil freezes, sieve and disinfect sawdust and sheep manure, mix them into a 1:3 mixture (1 part sawdust, 3 parts sheep manure), and cover the seedlings evenly, preferably covering over the tops of the seedlings.