Seedling raising techniques of Walnut seedlings

Walnut, also known as walnut, Qiang peach, etc., is a plant of the walnut family, and is called the world-famous "four dried fruits" with almond, cashew and hazelnut. It is resistant to drought and disease, adapts to a variety of soil growth, and likes fertile and moist sandy loam. It is often found in places with deep soil layers on both sides of mountain valleys, which is of great cultivation value. Let's take a look at the breeding techniques of walnut seedlings.

Seed selection

When selecting walnut seeds, 20-40-year-old excellent individual trees with strong adaptability, high and stable yield, thin shell, full kernel, easy kernel extraction, high kernel rate and oil content, and strong growth should be selected as seed collection mother trees. In general, in September, the exocarp changes from turquoise to yellowish brown when the seeds mature. However, the seed used should be harvested 10-15 days later than commercial walnut, which is beneficial to improve the germination rate. After harvesting, pile up, remove the green skin, seed walnuts do not need to rinse, can be directly dried, drying seeds should be spread flat in a ventilated and dry place, should not be placed on the cement floor, wood or iron board direct exposure, so as not to affect the seed vitality. Walnut seeds have no post-ripening stage, and the seeds sown in autumn can be sown with green skin after harvest, while the seeds sown in spring can be stored for a long time and should be stored in a ventilated and dry place of about 5 ℃.

Select land for nursery

In the process of raising walnut seedlings, whether in the field or in the self-sufficient courtyard, the selected nursery requires flat terrain, leeward to the sun, loose soil, fertile soil, convenient irrigation and good drainage. After selecting the nursery land, it is necessary to carry out deep ploughing or deep ploughing, fine soil preparation, so that the upper and lower soil is solid, the soil is fine and flat, and the fertile soil is uniform. Generally carried out in front of Frosts Descent, sufficient base fertilizer should be applied at the same time of soil preparation, including 3000-5000 kg of farm manure per mu and 50 kg of superphosphate per mu. After the end of soil preparation, the length varies according to the topography and the amount of seedlings, and the seedbed is one meter wide.

Seed treatment

Walnut seeds sown in autumn do not need to be treated, but can be sown directly with green skin. During spring sowing, seed treatment should be carried out before sowing to ensure germination, and the usual method is cold exposure to the sun. The method of cold invasion and sunburn is to soak the seeds for 7 to 10 days and change the water once a day to make the seeds absorb water and swell. After a small number of cracks in the seeds are removed, the seeds can be sowed in the soil or on the ground for 2 hours or 3 hours.

Sowing management

1. Sowing period: walnut is divided into autumn sowing and spring sowing. Autumn sowing should be carried out before the soil freezes, not too early or too late, otherwise it will affect the germination ability. As autumn sowing seeds are vulnerable to rodent damage and rabbit damage, spring sowing is often used to raise seedlings. Spring sowing should be carried out in late March and early April after the soil is thawed.

2. Sowing method: walnut is often sown on demand. In the finished seedling bed, the row spacing is 20cm to 30cm and the plant spacing is 15cm. The seed suture line should be perpendicular to the ground and the seed tip should be placed to one side, so that the root system of the seedling is extended, the seedling stem is upright and the growth is robust. The sowing depth is 6 cm 8 cm and the soil cover is 9 cm 12 cm after sowing. The principles of deep autumn and shallow spring, deep drought and shallow waterlogging should be followed when sowing.

3. Sowing rate per mu: the sowing rate of walnut varies with plant row spacing and seed size and quality. generally, dry walnut is planted at 100kg / mu, about 9000kg / mu, 8000kg / mu and 400kg / mu, respectively. In addition, whether in the field or in the courtyard, it is best to use the spring film mulching method to raise seedlings, so that the seedlings emerge early, the seedlings emerge neatly, and the growth cycle of seedlings is long.

4. Fertilization and irrigation: walnut sprouts about 20 days after spring sowing, and comes out about 40 days, generally not too dry, no irrigation before emergence, so as not to cause ground hardening, if the soil moisture is too poor, it can be watered in time, and shallow ploughing and loosening soil can be carried out. When the seedlings come out, in order to speed up their growth, they should be irrigated in time. May and June are the critical period for seedling growth, watering 2 or 3 times according to soil moisture, combined with topdressing available nitrogen fertilizer, 10 kg urea per mu, and more rainfall in July and August. Phosphorus and potassium fertilizer can be applied appropriately.

5. Weeding in mid-tillage: weeds in walnut spring nursery grow fast, have strong fecundity, compete with seedlings for water and nutrients, and some weeds are vectors and parasitic places for diseases and insect pests, so nursery land should be ploughed and weeded in time.