Thin-skin walnut cultivation technology
Cultivation technology
Soil preparation
Thin-skin walnut plant row spacing is 4 m × 5 m to 4 m × 6 m It is more reasonable. The length and width of the planting hole should be 80 cm each and the depth should be 100 cm. The topsoil should be backfilled and the soil should be firmly planted while backfilling. If possible, 20 to 50 kg of decomposed organic fertilizer can be applied to each hole, but attention should be paid to mixing the fertilizer with the soil. Backfill evenly to avoid root burn. After backfilling, fill the sinkhole with water and fill the sinkhole with topsoil after 2 to 3 days.
Planting
Before planting, seedlings must be screened to select high-quality, strong seedlings with complete root systems, substantial tissues, full terminal buds, and no disease or injury. When planting, it is required to form horizontal and vertical rows. The planting depth of seedlings should be equal to the original soil imprint of the seedlings. First, dig a 30 cm square pit in the center of the planting hole, and place the seedlings in the middle. When planting, the roots should be stretched and evenly distributed. Fill the soil while stepping firmly, and gently shake the seedlings up to prevent the roots from turning upward. Make the root system and the soil closely connected to each other, fill up the soil and compact it, dig out the tree tray, irrigate it fully, and build the soil firmly after the water has seeped out. In areas with poor water conservancy conditions, the mud method can be used for planting, that is, dig a 30 cm square pit in the center of the planting hole, fill it with a bucket of water, fill it with soil and mix it with mud (the mud is thick enough so that the seedlings do not fall after being inserted), and the seedlings are inserted upward. Lift gently to stretch the roots, plant at the same depth as above, and cultivate the soil firmly.
Cold protection and anti-striping
Because walnut saplings (especially current-year seedlings) have large branch piths, high water content, and low cold resistance, they are susceptible to winter frost damage and early spring withdrawal. Article (physiological drought). Main preventive measures:
In winter, bury the seedlings in soil to prevent cold. In principle, all above-ground parts of the seedlings should be buried tightly.
If the size of the seedlings is large and it is difficult to bury them tightly in the mound, the exposed part above the mound should be wrapped with a layer of paper (preferably toilet paper), and then wrapped tightly with plastic film.
Use petroleum jelly or animal oil to coat all branches.
Irrigation in early spring
Before the walnuts germinate in the second spring (usually before Qingming Festival), remove the cold-proof soil and branch wrappings, and dig out the tree borders (1.5 m wide) or tree trays , fill enough water to turn green in time, and water it in a timely manner depending on the moisture content. If possible, you can cover the tree tray with 1 m2 of plastic mulch after watering to retain moisture and increase the ground temperature.
Drying
If the height of the seedlings reaches more than 1 m, the buds should be fixed at a full bud zone of 0.8 ~ 1 m before germination in spring; if the specifications of the seedlings do not reach the fixed height, the buds should be dried After the seeds germinate, only the terminal buds are left, and the sprouts in other parts are wiped out to concentrate nutrients and promote the growth of the terminal buds to reach the set stem height as soon as possible.
Pest and Disease Control
The main pest that harms walnut saplings in spring is the black velvet beetle. During its adult stage, its pseudo-death behavior can be used to kill it manually in the evening or early morning after it vibrates, or it can be killed by using tree branches. Protect with an insect-proof net; for chemical control, you can use chemicals such as Lesbon, cypermethrin, and Uranus.
Seedling technology
1. Walnut seedling grafting technology
The rootstock is a seed whose first true leaf has not yet unfolded and a hypocotyl thickness of more than 0.6cm. Seedlings (seedlings propagated by seeds), scions are collected from mature annual branches of superior varieties. March is the best time for scion wound healing and a favorable time for seedling grafting. To this end, it is necessary to use a greenhouse and sow seeds early so that the walnut seedlings can meet the grafting requirements and develop into seedlings in March, and then be moved to the field in April.
Construction of simple greenhouse (1) Electric hotbed: cement structure, iron frame glass ceiling, pool depth 80cm, 20cm stones underneath, and a water outlet. Then lay 5-10cm of fine sand, install the heating wire on the wooden strips fixed on both sides, and then spread 25-30cm of humus soil. (2) Earth greenhouse: It adopts the Huilong fire kang heating method and uses coal as fuel. Generally, it is semi-underground type, covered with double-layer plastic film.
Walnut seed collection and preservation The walnut harvest period is early September, and the harvest of walnuts for seedling grafting can be postponed to mid-to-late September. After harvesting, peel the skin, dry it in a ventilated place, put it into sacks and store it in a ventilated and dry place.
Sowing and management of walnuts in the greenhouse are sown in late December. Soak the seeds in warm water for 3-5 days before sowing.
When sowing, leave a slight gap in the middle of the seed and fill it with fine soil so that the suture line is perpendicular to the ground and the seed tip is slightly upward. Cover the seeds with 4-6cm of soil. The soil moisture content is maintained at 10%-12%. The seeds will begin to crack 20-30 days after sowing and can be grafted after 40-60 days.
Collection and storage of scions: It is appropriate to collect walnut scions from late February to early March. The scions should be strong, mature annual branches with small pith, short internodes and full buds. Generally, the grafting survival rate is higher at the junction of spring and autumn and the branch sections with terminal buds. The collected scions are put into plastic bags, filled with wet sawdust, and stored in a cold storage at 3-5°C. They can also be wrapped in plastic film and buried in sand and soil in a cool place indoors.
Walnut seedling grafting technology: When the first pair of true leaves of the walnut bud is about to unfold, cut off the root bud, cut along the cotyledon 2-3cm along the petiole along the center of the hypocotyl, and select the rootstock When the scion is as thick as possible, use cleft grafting to insert the scion and tie it with a plastic strip. When grafting, try to use walnut seedlings with strong and upright epicotyls.
Indoor healing management of grafts: The appropriate healing temperature is 23-25°C, the moisture content of the matrix is ??maintained at 10%-12%, the indoor air humidity can be controlled above 80%, and ventilation is appropriate. After healing, more light should be transmitted to strengthen the prevention and control of diseases and insect pests. In case of mold infection and insect and fly damage, the plants can be sprayed with 0.5% potassium permanganate and 0.15% formaldehyde solution in time.
2. Current nursery construction technology
When the grafted walnut seedlings grow 2-3 leaves (early April), the seedlings are hardened indoors. The ear picking garden requires deep soil, fertile soil, and watering conditions. Dig holes at fixed points according to a spacing of 2m×3m between plants. The length, width and depth of the holes are 80cm×80cm×60cm. Apply half a basket of circle fertilizer and a spoonful of soil to each hole. When the daily average outdoor temperature rises to 10-15°C, start transplanting seedlings to the ear picking nursery. Irrigate the seedlings with water before they are raised, dip the roots in mud after the seedlings are raised, shade them with branches after planting, and water them in time and sprinkle the leaves. After the grafted walnut seedlings are transplanted into the field, management must be strengthened. Before the rainy season (late June), 25g of urea or compound fertilizer is applied to each plant to promote its rapid growth. In order to ensure the safe overwintering and rapid growth of the improved walnut seedlings in the ear picking garden in the following year, 7.5kg of fertilizer is applied to each plant before the cold, and cold-proof measures such as soil cultivation and irrigation are taken.
High-Yield Technology
If you want to grow high-quality thin-skinned walnuts, you must first select high-quality seeds. Plump and well-proportioned seeds are necessary conditions for good seeds. First, put the thin-skinned walnut seeds into a pot and pour water into them. , press the thin-skinned walnuts with your hands to fully soak them, wash and soak them, take them out, dry them properly, and then turn the sand pile deeply to check whether the dryness and humidity of the sand are appropriate. Finally, pour in the soaked thin-skinned walnuts and cover them with soil. Pay attention to the soil layer to be even and compact it after covering. After germination, the seeds can be sown.
In the past, people often used the saying "grandfather plants a tree and his grandson reaps the fruit" to describe the late-bearing habit of thin-skinned walnut trees. But now, this problem can be easily solved. Its secret lies in the grafting technology of thin-skinned walnuts. Thin-barked walnut grafting can make saplings bear fruit early, old trees rejuvenate, and prolong the fruiting life. Cut the trunk 1.2 to 1.5 meters above the ground and flatten the cut surface with a knife. Larger trees can be grafted with multiple heads. The scion has not sprouted, lost water, or become moldy. The width of the grafting bud is 0.8 to 1 cm and the length is 3 to 5 cm.
The first step in grafting technology is the scion, which is the branch from the tree that grows in the current year. After taking it off, use a square sprout, 20 to 25 centimeters above the ground, cut a square equal to the size of the sprout, then stick the sprout and the sprouts from the tree on it, and use it later. Wrap the special film and tie it tightly, then leave three or four auxiliary leaves on top to remove the top. Due to unfavorable factors such as the large flow of damage during thin-skinned walnut grafting, the scions being bent, and the pith being large, the grafting process must have sharp tools and accurate and standardized operations to increase the survival rate. Generally, after seven days, you can see whether the grafted seedling is alive. After 10 to 15 days, you can cut it. When the new shoot grows to seven or eight centimeters, you can remove the plastic sheet and use scissors to cut the opening from the back. , untie the plastic sheet so that the seedlings can grow healthily.
Improving the planting survival rate and planting saplings are an important part of establishing a thin-bark walnut garden, and are also the basic work to achieve strong trees, early feeding, and high yields. The quality of planting must be ensured to enable the growth of saplings. Robust and successfully pass the development stage, laying a solid foundation for increasing production. Only high-quality seedlings can effectively utilize cultivation conditions and achieve multiple results. The seedlings are required to be of pure variety, with complete main roots and lateral roots, free of diseases and insect pests, and strong resistance to stress. It is best to have strong seedlings that are 2-3 years old, with a height of more than one meter, a dry diameter of not less than one centimeter, and more fibrous roots to ensure survival and robust growth. Generally, the diameter and depth of the planting hole are not less than 0.8-1 meter. After digging the planting hole, mix the topsoil and soil and manure and fill it into the bottom of the hole. Then put the seedlings in with the grafting port facing north, mainly to prevent wind. Blow, then stretch the roots and fill in soil from the sides to the center. Fill the soil firmly in layers to make the root system evenly distributed. Build the soil until it is level with the ground. After it is fully solid, dig out the tree tray and irrigate it fully. When it is almost full, lift the sapling up. The purpose of this is to make the roots appear Make it smooth and seal it with soil after water seeps out. The planting depth of the seedlings can be slightly 5 cm deeper than the original seedling depth, and the seedlings should be watered again seven days after planting.
After filling the soil, cover it with mulch. The entire tree pit should be covered tightly. It is usually 80 cm square. Poke a hole in the middle, then cover it from the top. Cover the surrounding area tightly with soil. The gap in the center should also be covered with soil. Cover tightly, and after 15 days, remove the mulch and water it, and then water it every half a month to facilitate the survival of the saplings. The purpose of covering the mulch is to increase the ground temperature and protect the newly planted saplings. Water is very needed. If the watering is not timely, the saplings will die. Generally, for newly planted saplings, if they are watered and covered with mulch, half a month is enough to maintain the water they need for this half month.
Winter management techniques
1. Pruning Winter pruning of thin-skinned walnuts is better than spring pruning. Walnut trees have strict requirements on pruning time. The best period is after the fruit is harvested and before the leaves turn yellow, and the amount of pruning should not be too heavy. Thin-skinned walnut tree shapes are mainly evacuation layered and spindle-shaped. Young trees and trees in the early fruiting stage mainly sparse overly dense branches, cross branches, and overlapping branches, control and utilize secondary branches, shorten and modify long branches, and prune back branches, drooping branches, and branches infected by diseases and insect pests, so as to achieve the optimal growth of branches in the crown. It can be evenly distributed, and the pruning principle is to not affect each other. The focus of pruning mature fruit-bearing trees is to adjust the relationship between growth and fruit. Shorten or thin out the vigorously growing secondary branches on the periphery of the crown, and remove overly dense branches, cross branches, overlapping branches, thin branches, and branches infected by diseases and insect pests; when pruning late-fruiting thin-skinned walnuts, pay attention to thinning out densely packed branches inside. , if necessary, thin out some overly dense branches, cultivate fruiting branch groups in a planned way, and maintain the high-yielding tree vigor. The auxiliary branches should be treated based on the principle of facilitating the growth of the main side branches, and the back and lower branches with strong growth should be removed.
2. Whitening the trunks of young trees It is very important to whiten the trunks of young trees. Whitening can prevent longhorned beetles, rot, dry rot, sunburn, frostbite, livestock gnawing, etc. The whitening formula is: 18 parts of water, 1 part of salt, 6 parts of lime, 0.3 parts of oil, and 1 part of lime sulfur mixture.
3. Water and fertilizer management Generally, there are three critical periods for watering high-quality thin-skinned walnuts: before freezing, before germination, and during the fruit expansion period. Watering before freezing is particularly important. First, watering after picking fruits can effectively promote the decomposition of base fertilizer, increase the nutrient reserves of the tree before winter, improve the ability to survive the winter, and is conducive to germination and flowering in the following year. 2. Carry out after the leaves fall and before the soil freezes to prevent freezing and drought in early spring. The third is to play the role of reducing the insect population base.
The key period for fertilizing thin-skinned walnuts is to apply base fertilizer after autumn. It is generally based on farmyard manure or decomposed organic fertilizers such as firewood and straw. It should not be lower than the standard of ten pounds of fertilizer for one pound of fruit. It is appropriate to use ring or Furrow fertilization method. For top dressing before germination, apply 0.2 to 0.5 kilograms of urea, diammonium phosphate or special fertilizer for fruit trees to each sapling, and 0.5 to 1.5 kilograms to each fruiting tree. Hole fertilization should be used. Appropriate top dressing is also required during the fruit expansion period.
Problems in cultivation and production
1. The orchard occupies poor conditions. The soil thickness is thin and cannot meet the needs of walnut development; the terrain is too low and the soil moisture is high in the later season, which is not conducive to the timely stop of the growth of new shoots; the low-lying terrain is not leeward and prone to frost damage.
2. There is a lack of seedlings in some gardens, and there are a large number of live walnuts mixed in.
3. The varieties are messy, the growth is uneven, the fruit bearing is uneven, and the differences between the plants are too great.
4. Some of the main trunks below the surface have suffered from freezing damage or mechanical damage, forming many strip-shaped scars, resulting in tree weakness, premature yellowing of leaves, and even the death of the entire tree.
5. Improper pruning time and improper pruning methods are not conducive to the growth, development and flowering of walnuts.
6. Inadequate pest and disease control. Walnut black, thorn moth, beetle, gray spot, dry rot, canker, etc. are not prevented and controlled in time, which seriously affects the development and fruiting of the tree.
7. With heavy planting and neglect of management and laissez-faire management, some walnut orchards are in danger of being eliminated.
Specific methods to solve the problem
1. Grafting: Both seedlings and inferior varieties in the garden can be re-grafted. The grafting method is tooth-to-tooth grafting, which is simple and easy to do. , it should be noted that: the grafting part should be selected from one-year-old strong branches; the scion should be collected from the strong developing branches on the periphery of the crown of the high-yielding tree, and the picking time should be in mid-March. Grafting can be carried out in the first ten days of the month. This method is fast and the survival rate can reach more than 95%. When the grafted buds grow to 15 ~ 20 cm, the plastic strips can be untied and removed, and pillars must be erected to tie the grafted twigs to prevent them from being broken by the wind.
2. Improve the soil: For gardens with poor site conditions, leaking fertilizers, water leaks, and poor soil, methods of removing soil and applying more organic fertilizers can be used to improve the soil to maintain the normal growth and fruiting of the tree. .
3. Prevent freezing damage: Before winter comes, you can build an adobe wall or a temporary straw wall to block the wind in the west and north of the walnut orchard. After snowfall, clear the snow around the root neck and on the tree promptly to protect it from freezing damage.
4. Timely pruning: Walnut trees have strict requirements on pruning time. Pruning is mainly done at the autumnal equinox in a year, and the pruning amount should not be too heavy at one time. Especially for young trees, the branches in the crown can It can be evenly distributed, and the pruning principle is to not affect each other. The tree shape can be evacuated layered shape or free spindle shape, and the stem height is required to be 1 ~ 1.2 m. In mid-September every year, the leggy new shoots are cut off from the old leaves. Thin branches, dry branches, and diseased and insect-infested branches can also be removed after budding in spring, but as little scars are made on the main trunk as possible. Large saw cuts during pruning should be painted immediately to protect them.
5. Whitening the trunks of young trees: It is very important to whiten the trunks of young trees. Whitening can prevent longhorned beetles, rot, dry rot, sunburn, frostbite, livestock gnawing, etc. The whitening formula is: 18 parts of water, 1 part of salt, 6 parts of lime, 0.3 parts of oil, and 1 part of lime sulfur mixture.
6. Prevention and control of pests and diseases: Before germination in early spring, spray the whole tree once with 5 Baumé lime sulfur mixture, and once in late May to early June to control walnut black (leg-lifting moth). : Cypermethrin thiophanate methyl. Spray insecticides twice from July to August to prevent thorn moth pests. Pay attention to the stem borer pests in early spring and August. Once found, use a syringe to inject 50 times 1605 into the insect hole.
Walnut planting technology to China Organic Agriculture Network!