Speaking of walnuts, the first thing we think of must be tonifying the brain. In fact, small walnuts can not only strengthen the brain and beauty, but the latest research also found that eating walnuts often can reduce human cholesterol and protect cardiovascular system. So how are walnuts grown? Let's go and have a look~
Walnut planting technology walnut breeding method (basic knowledge): the best breeding time: walnut is taken out and sown in spring and cut in winter and spring;
Best growth soil: walnut is suitable for a variety of soil growth and likes fertile and humid sandy loam;
Growth humidity requirements: Walnut needs sufficient water during growth and development. However, walnuts are not waterlogging resistant. Walnuts sown in ponding land are prone to decay, which is most suitable to be planted next to water channels in mountainous areas, rivers and ditches;
Optimum growth temperature: Walnut belongs to thermophilic tree species. The suitable growth temperature range and frost free period are: annual average temperature 9-16 ℃, extreme minimum temperature - 25 ℃, extreme maximum temperature below 38 ℃, frost period below 150 days;
Best growth light: walnut is a light loving fruit tree, which requires sufficient light. When building a garden in mountainous areas, it is better to choose the south slope. The annual sunshine hours should be more than 2000 hours to ensure the normal growth and development of walnut. If it is less than 1000 hours, the core, shell and nucleolus are poorly developed.
Precautions for walnut cultivation technology: fertilizer application: Lime shall be applied before acid soil colonization, and attention shall be paid to soil deep turning or tree disk deep turning, so as to facilitate early fruit bearing, high yield and stable yield of young trees. The fertilization rate of walnut is: 1 ~ 2-year-old young trees, n 0.1kg per plant per year, P.K fertilizer is applied appropriately according to the soil content; Apply 150 ~ 250kg of stable manure to adult trees. Phosphate fertilizer 1.5 ~ 2.5kg, ash fertilizer 2.5-5kg. Topdressing is applied 2 ~ 3 times a year (before germination, after flower falling and fruit hard core stage), and topdressing nitrogen fertilizer is 1 ~ 2.5kg per plant.
1. Base fertilizer. The base fertilizer should be early, which should be completed after harvest and before defoliation. Each adult tree should be applied with 100 ~ 200kg high-quality organic fertilizer.
2. Topdressing. The suitable period of topdressing is before flowering, young fruit expansion and fruit hard core. Generally, 0.8 ~ 1kg Tianji brand nitrate phosphate fertilizer is applied to each plant every time.
3. Spray fertilizer on the leaves. The fertilizer spraying period is flowering stage, long-term shoot speed, flower bud differentiation stage and after harvest. The commonly used fertilizer spraying types are 0.1% ~ 0.2% boric acid, 0.5% ~ 1% ammonium molybdate, 0.3% ~ 0.4% copper sulfate, etc.
Key points of watering: watering walnut trees every day will cause the soil to be too wet and have no porosity, resulting in anaerobic respiration in the roots, then some or even all of the roots rot, and finally the tree will die. Moreover, when watering at night, the soil is dried for a day, the temperature is too high, the water temperature is low, and it is easy to rot roots. Watering should also be in the morning, and the ground temperature and water temperature are appropriate.
Pruning Essentials: 1. Shaping and pruning of young trees
1) Sparse and dispersed type: the central leading branch is obvious, with 5-7 main branches, divided into 2-3 layers. This kind of tree has many branches, large crown and high yield. It is suitable for deep and fertile soil and varieties with upright branches.
2) Natural open center type: suitable for varieties with thin soil and open crown. The central leading stem is not obvious, with 2-3 main branches, which is a 2-branch or 3-branch structure.
3) Upright cylindrical type: due to high mountains and deep ditches, lack of light, walnut has strong uprightness and obvious central stem, which is cultivated into an upright cylindrical shape.
2. Pruning of result trees
1) Pruning of results mother branches: the strong branches born in one year around the crown are often the results mother branches of next year, which are generally not cut short. However, when there are too many results mother branches, the crown will be closed and the ventilation and light transmission will be affected. Some weak results mother branches must be properly removed to stabilize the yield and promote the normal development of the tree.
2) Pruning of extension branches: for 15-30-year-old trees in full fruit stage, the 1-year-old extension branches drawn from the withered part of the main branches at all levels around the crown can be short cut at 2-3 buds under the withered buds.
3) Pruning of long branches: long branches are mostly formed by the germination of dormant buds on the inner bore backbone branches, which occur more in vigorous adult trees and aging trees, and are mostly cut from the base.
4) Pruning of drooping branches: retract at the branch and cut off the dry branches of diseases and pests at the same time. Over dense drooping branches shall be cut off year by year.
Walnut planting technology
Breeding points: walnut is mainly grafted. The rootstock is 1 ~ 2-year-old seedlings of this rootstock or iron walnut. The seed sand shall be stored for more than 60 days and taken out for sowing in spring. The row spacing of drill sowing is 30 ~ 40cm, the plant spacing is 12 ~ 15cm, and the soil covering is about 5cm. When sowing, the suture of the seed is perpendicular to the ground, which is conducive to the smooth growth of radicle and bud. The suitable time for branch grafting is from the beginning of spring to rain, and the best time is when the sap begins to flow and the top bud of rootstock has sprouted. The suitable budding period is around the spring equinox, when the rootstock starts to shoot and the top bud spreads its leaves, when the bark is easy to peel off. After grafting, the interface and scion are covered with plastic bags and wrapped with wet sawdust for heat preservation, and the grafting survival rate is more than 95%. Walnut cotyledon seedlings are grafted. When the seed buds will display the true leaves, the rootstock buds are cut at 1 cm above the cotyledon petiole and split. After that, they are placed in the healing pool or simple greenhouse. After survival, they are transplanted into the field. The survival rate is more than 80%, which can shorten the seedling raising time.
Thin shell Carya cathayensis can also be cultivated by root cutting. The roots of 1-4-year-old seedlings with a thickness of 1 or 5 cm are selected and cut into 10 cm long. The survival rate can reach 90% ~ 100% by cutting in winter and spring. It can also be propagated by tillering, layering, cutting and grafting. Walnut has few lateral roots. The main root should be cut off at the seedling stage to promote lateral roots and improve the planting survival rate. The planting density is 210 ~ 285 plants / h ㎡. It can be planted in spring and autumn. Because the peach blossom is dioecious and requires cross pollination, a pollination tree shall be configured.
Pest control: anthrax
Walnut branch blight: the disease is a fungal disease. It mainly endangers the branches and causes the branches to wither. Generally, the damage rate of plants is about 20%, and the serious one can reach 90%. The disease mainly affects tree growth and yield.
The symptoms of the disease are that after 1-2-year-old branches or side branches are damaged, they gradually dry from the top to the trunk, and the leaves turn yellow and fall off. Dense small black spots are produced on the dead branches. When the humidity is high, mucus flows out and black tumor like processes are formed. The pathogen overwinters on the diseased branch and invades through the wound. The disease only endangers weak trees.
Insect pests: leaf eating pests such as aphids and moths.
Control method: destroy, remove diseased branches and burn them in a centralized manner. Drugs: the control time and chemicals used are the same as those of walnut anthracnose.
Expand walnut knowledge - walnut varieties: the hometown of walnut is Iran in Western Asia. Zhang Qian brought it back to China after he went to the western regions in the Han Dynasty.
1. According to the origin classification, there are Chencang walnut, Yangping walnut and wild walnut;
2. Classified by maturity, there are summer walnut and autumn walnut;
3. According to the degree of smoothness of fruit shell, there are light walnut and hemp walnut;
4. According to the thickness of fruit shell, there are two categories: thin shell walnut and thick shell walnut.
Existing walnut species in China:
According to the book "Chinese walnut", the existing walnut plants in China (including introduced and discovered natural hybrids) are divided into 3 groups and 8 species.
Walnut group: walnut, iron walnut
Juglans mandshurica group: Juglans mandshurica, wild Juglans mandshurica, Ma Juglans mandshurica, Keppel Juglans mandshurica and heart-shaped Juglans mandshurica.
Black walnut group: black walnut.