1. Cultivation techniques: 1. Planting time: Walnut is suitable for growing on warm sandy loam and black loam with deep soil layer and good drainage, and should be planted on sunny slopes and leeward places. To develop walnuts in barren hills, we must first build terraces, dig large fish scale pits and do a good job in soil and water conservation. Planting time: early planting in spring after soil thawing, early planting in autumn after defoliation and early planting after soil freezing, and early planting in autumn before soil freezing after defoliation. In arid areas in spring, the survival rate of autumn planting is higher than that of spring planting. The second spring sprouted early and thrived. Seedlings planted in autumn should be ridged to prevent drainage. Methods: The trunk of seedlings was bent into an arch to fix the soil, and the trunk was not exposed. The following spring, I broke ground and straightened the trunk. 2. Planting method: The taproot of walnut seedlings is very long, and the depth and width of the pit are 0.8- 1 m respectively. First, the topsoil and base fertilizer are filled at the bottom of the pit, about 20 cm away from the pit surface. When planting, use scissors to trim the seedlings whose roots are soaked and fully absorb water, put them vertically in the into the pit, spread their roots around, then firmly fill them until they are flush with the ground, then fill them with water and seal them. Second, shaping and pruning: it is a very important cultivation technique to make walnuts bear fruit early and have high and stable yield. The pruning period of walnut is different from that of ordinary fruit trees. This is done before the leaves turn yellow after the fruit is picked. In North China, it is best to prune between "white dew" and "cold dew". Pruning at this time, although the temperature is low, the wound heals slowly, but the nutrient loss is less. Small trees can be pruned early, because they have no fruit, and they can start pruning at the "Summer Festival". Spring pruning is generally carried out around the "long summer". It's too late, because the branches and leaves are too big, they consume too much nutrients, which is not conducive to the growth of trees. 1, young tree pruning: mainly to cultivate the tree skeleton, lay a good foundation, quickly expand the crown, and promote early fruiting and high yield. Walnut trees are generally sparse and scattered, naturally comfortable. (1) Sparse layer dispersion: the central dominant tree is obvious, and 5-7 main branches are divided into 2-3 layers, so that there are many branches in the tree, the crown is large and the yield is high. The key points of plastic surgery are to fix the stem height at 1.5-2.5 meters, the soil conditions are poor, the remaining stems should be low, and the position and direction of the main branches should be properly configured. The main branch spacing is1-1.5m, so it should not be too close. The first of the three main branches of the base is about 1.5m away from the main branch. If the distance is too close, the door side will be formed, and the distance between the outer branches of the crown should be reduced. Attention should be paid to maintaining the growth advantage of central leading branches. Under normal circumstances, it is not easy to change the head, which is an important feature different from other fruit tree pruning. (2) Natural joy: the central main stem is not obvious, with 2-3 main branches, showing a 2-fork or 3-fork structure. In order to accelerate the crown expansion of young walnut trees, increase the number of branches, realize fruit setting and early high yield, summer pruning and autumn pruning can be used to promote more lateral buds to germinate new branches. In summer, when the growth of broken branches is coming to an end, cut off the top 2-3 buds from the developing branches over 50 cm to promote the germination of lateral buds and enrich branches, and increase the number of branches in the coming year. In autumn, cut off the unfinished part at the top of the extended development branch or one third to one quarter of the branch length, and cut it on the plump outer bud in the middle and upper part, so that the crown will expand year by year and more development branches will be drawn. 1 The thin and weak branches that are too dense can be pruned appropriately. 2. Pruning of fruiting branches: The top buds of fruiting mother branches of walnut are mixed flower buds, so it is generally not allowed to prune every branch, only sparse branches, dead branches, pest branches and overlapping branches are pruned to facilitate ventilation and promote the growth of fully robust fruiting mother branches and development branches. (1) Pruning of fruiting mother branches: robust branches growing around the crown in 1 year are usually fruiting mother branches in the second year, and are generally not cut short. However, if there are too many fruiting mother branches, the crown will be closed, which will affect ventilation and light transmission. Therefore, it is necessary to prune some thin fruiting mother branches appropriately to stabilize the yield and promote the normal development of the tree. (2) Pruning of extended branches: For the 15-30-year-old trees in full fruit, the 1 year-old extended branches extracted from the top of each main branch at the periphery of the crown can be cut short at 2-3 buds below the terminal bud. If the top branches are not full, they can be cut off at the full buds to enlarge the crown and increase the fruiting parts. (3) Pruning of long branches: Long branches are mostly germinated by hidden buds on the main branches of the inner room, which mostly occur in mature trees and aging trees. In the past, most of them were isolated from the base, which was called "clean room". In recent years, we have begun to use the fruits of long branches. According to the experience of Hebei, Shandong and other provinces, according to the growth position and growth intensity, the long branches in the cavity with full buds can be cut short at one-half to one-third places, and fruiting branches can be formed in 2-3 years after cutting short, which can supplement the gap, expand the fruiting range and achieve the purpose of three-dimensional fruiting. (4) Pruning of drooping branches: retract at the bifurcation, and cut off the trunk branches of diseases and pests at the same time. Too dense drooping branches should be cut off year by year. Treatment measures of walnut trees after freezing injury
After the walnut tree is frostbitten, anti-freezing measures must be taken as soon as possible to avoid affecting the yield and diseases in the coming year.
1, luggage protection
(1)4-5 walnut trees are damaged by freezing. In order to prevent the deterioration of freezing damage and the occurrence of rot, we should immediately apply tree protector or white the trunk.
(2) Clear the snow around the trunk in time after snow, and the ground temperature will rise. After the surface is thawed, the trees under 4 years old are covered with plastic film with the trunk as the center, covering an area of about 1 m2.
2. Fertilizer and water
(1) Fertilize and water the soil immediately after thawing and before germination (first half of March). The annular or radial fertilization ditch method was adopted, and 50 kg of organic fertilizer and 0/-2 kg of urea were applied to the big trees. Apply 0.2-0.5 kg of urea to young trees and water them immediately after fertilization. Spraying the mixed solution of 0. 1-0.3% urea and potassium dihydrogen phosphate on the leaves for topdressing outside the roots.
(2) After the soil is thawed, the pine trees and conditional woodlands should be ploughed and loosened as soon as possible.
3, timely pruning
(1) Before budding and spreading leaves (from mid-late March to mid-April), identify the frost damage parts of the branches of trees with frost damage level above 2, and prune them appropriately. Cut off the dead parts of branches, and apply 50 times of 3-5 degree sulfur mixed solution or 50% thiophanate-methyl wettable powder to the cut mouth for disinfection. Transport the cut branches out of the forest land for centralized burning.
(2) In the first half of May, select and keep the sprouting branches and new shoots on the pruned branches. Select and cultivate new backbone branches and fruiting branches, and trim back branches, upright branches, over-dense branches, cross branches, etc. And restore the tree and shape as soon as possible.
(3) In the middle and late May, select and preserve the whole overground part and grafted part of the frozen seedlings and trees, select the trunk of new young trees to be cultivated and new branches to be grafted, cut off other new branches and sprout in summer.
4. Prevention and treatment of rot disease
(1) Walnut trees are prone to secondary diseases-rot after freezing injury. In early spring (early April), once the rot disease is found, it should be prevented in time;
Scraping off diseased spots: Scrape off rotten diseased spots with a sharp knife, and the scraping mouth becomes a "long shuttle shape" with smooth and complete edges. Scrape 0.5㎝ wide intact cortex from the lesion, leaving no diseased tissue.
Usage: Use 50 times solution of Shuguan bacteria or 50% thiophanate methyl wettable powder or 50% bacitracin wettable powder or 5- 10 Baume mixture to disinfect the scraped wound, and then brush Bordeaux solution to protect the wound.
5. Scratch protection
After applying medicine to the curettage, wrap the curettage with cloth or dark plastic strips to promote wound healing. Collect the scraped diseased tissues in a centralized way and transport them out of the forest land for burning. Never leave the scraped diseased tissue in the woodland. To prevent rot, we should "scrape early, scrape small and scrape clean".