cultivation techniques
Carry out soil preparation
The row spacing of thin-skinned walnut plants is 4m×5m ~ 4m×6m, and the planting holes are 80 cm long, 80 cm wide and 100 cm deep, which is practical and backfilled with topsoil. If possible, 20 ~ 50 kilograms of decomposed organic fertilizer can be applied to each hole, but attention should be paid to mixing the fertilizer with the soil before backfilling to avoid burning the roots. Fill the pit with water after backfilling, and fill the pit with topsoil after 2 ~ 3 d.
plant
Before planting, seedlings should be screened, and high-quality strong seedlings with complete roots, rich tissues, full terminal buds and no diseases and injuries should be selected. It is required to arrange in rows when planting. The planting depth of the seedlings is equal to the original soil footprint of the seedlings. First, dig a 30 cm square hole in the center of the planting hole, put the seedlings in the middle, spread the roots evenly when planting, fill the soil and step on it, gently lift the seedlings to prevent the roots from turning up, so that the roots are closely connected with the soil, fill the soil and step on it to make a tree tray, fill it with water, and cultivate the soil after water seepage. In areas with poor water conservancy conditions, the mud method can be used for planting, that is, dig a 30 cm square hole in the center of the planting hole, pour a bucket of water into the hole, fill it with mud, and stir it evenly (it is advisable that the mud is thin and thick after transplanting). After transplanting, the seedlings are gently lifted upwards, the roots are elongated, the planting depth is the same as above, and the soil is practical.
Anti-cold and anti-drop
Young walnut trees (especially those born that year) are prone to freezing injury in winter and bolting in early spring (physiological drought) because of their large pith, high water content and low cold resistance. Main preventive measures:
In winter, in principle, the ground part of seedlings should be buried tightly.
If the seedlings are large and it is difficult to bury them tightly with mounds, then the exposed part above mounds should be wrapped with paper (preferably toilet paper) first, and then wrapped tightly with plastic film outside.
Coat branches with vaseline or animal oil.
Early spring irrigation
Before the walnut germinates in the next spring (usually before Tomb-Sweeping Day), the cold-proof soil and branches are removed, the edge of the tree (1.5 m wide) or the tree disk is punched, and the green water is poured in time, and then the water is poured in time according to the water content. If possible, cover the tree tray with 1 m2 plastic film after watering to keep moisture and raise ground temperature.
Dinggan
If the height of the seedlings is above 1 m, the seedlings should be fixed in the full bud zone of 0.8 ~ 1 m before germination in spring; If the seedling size fails to reach the fixed stem height, only the terminal bud is left after germination, and other parts are erased to concentrate nutrition and promote the growth of the terminal bud to reach the fixed stem height as soon as possible.
Eliminate pests and diseases
The main pest that harms young walnut trees in spring is black velvet beetle, which can be killed artificially in the evening or early morning or protected by insect nets on branches by using its suspended animation in adult stage. Chemical control can choose levoben, cypermethrin, Uranus and other drugs.
Seedling raising technology
Grafting technology of walnut seedlings
Rootstock adopts seedlings (seedlings propagated by seeds) with the first true leaf unexpanded and hypocotyl thickness above 0.6cm, and scions are collected from one-year mature branches of excellent varieties. March is the best time for scion wound healing, and it is also a favorable opportunity for seedling grafting. Therefore, it is necessary to use the greenhouse to sow early so that the walnut seedlings can meet the grafting requirements, develop into seedlings in March and move to the field in April.
Simple shed construction (1) electric hotbed: cement structure, glass ceiling with iron frame, pool depth of 80cm, stone below 20cm, water outlet. Then mat 5- 10cm of fine sand, install the heating wire on the wooden strips fixed at both sides, and then spread 25-30cm of humus soil. (2) Earth shed: Huilong fire kang is used for heating, and coal is used as fuel. Generally, it is semi-underground and covered with double-layer plastic film.
The harvesting period of walnut seeds and preserved walnuts is early September, and the harvesting of walnuts for seedling grafting can be appropriately postponed to the middle and late September. Peel after harvesting, then dry in a ventilated place, put in sacks and store in a ventilated and dry place.
65438 planted and managed walnuts in the greenhouse in late February. Soak the seeds in warm water for 3-5 days before sowing. When sowing, leave a gap in the middle of the seed and fill it with fine soil, so that the suture line is vertical to the ground and the tip of the seed is slightly inclined. Cover the seeds with soil for 4-6 cm. The soil water content is kept at 10%- 12%. Cracking begins in 20-30 days after sowing, and grafting can be carried out in 40-60 days.
Collection and storage of scions The collection time of walnut scions should be from late February to early March. Scions should be annual mature branches with strong, small pith, short internodes and full buds. Generally, the grafting survival rate is high at the junction of spring and autumn and branches with terminal buds. Put the collected scions into plastic bags, fill them with wet sawdust, and store them in a refrigerator at 3-5℃, or wrap them in plastic film in a cool place indoors and bury them in sand.
Grafting technology of walnut seedlings When the first pair of true leaves of walnut buds are about to unfold, the rootstock buds are cut off, and the straight petioles on cotyledons are cut off along the center of hypocotyl, and scions with the same thickness as the rootstock are selected, inserted by split grafting and bound with plastic strips. When grafting, try to choose walnut seedlings with thick and upright epicotyl.
The suitable healing temperature of grafting room is 23-25℃, the water content of substrate is 10%- 12%, the indoor air humidity can be controlled above 80%, and proper ventilation is required. After recovery, it is necessary to transmit more light, strengthen pest control, mold infection and insect and fly harm, and spray plants with 0.5% potassium permanganate and 0. 15% formaldehyde solution in time.
2, when the nursery technology
When the grafted walnut seedlings grow 2-3 leaves (early April), the seedlings are tempered indoors. Harvesting nursery needs deep soil layer, fertile soil and irrigation conditions. Dig holes at fixed points according to the row spacing of 2m×3m, with the length, width and depth of 80cm×80cm×60cm, and apply half a basket of ring fertilizer and a spoonful of soil to each pit. When the daily average outdoor temperature rises to 10- 15℃, the seedlings will be transplanted into cuttings. Water before emergence, dip mud roots after emergence, shade with branches after planting, water in time and sprinkle water on leaves. Management should be strengthened after grafted walnut seedlings are transplanted into the field. Before the rainy season (late June), 25g urea or compound fertilizer was applied to each plant to promote its rapid growth. In order to ensure the safe overwintering and rapid growth of walnut seedlings in scion garden, 7.5 kg of ring fertilizer was applied to each plant before cold, and cold-proof measures such as soil cultivation and irrigation were taken.
High yield technology
If you want to grow high-quality thin-skinned walnuts, you must first choose high-quality seeds. Full symmetry is a necessary condition for good seeds. First, put the thin-skinned walnuts into the pot and inject water. Press the thin-skinned walnuts by hand to make them fully soaked. After washing and soaking, take it out and dry it properly. Then turn the sand pile deep and check whether the dry humidity of the sand is appropriate. Finally, pour the soaked thin-skinned walnuts, cover them with soil, and pay attention to the uniform compaction of the soil layer after covering. After germination, you can sow.
In the past, people often used to describe the habit of thin-skinned walnut trees to bear fruit late. Now this problem can be solved. Its secret lies in the grafting technology of thin-skinned walnut. By grafting thin-skinned walnuts, young trees can bear fruit early, and old trees can rejuvenate and prolong their fruiting life. Cut off the trunk from 1.2~ 1.5 meters above the ground, and flatten the section with a knife. For larger trees, multi-head grafting can be carried out. The scion has no germination, water loss and mildew. The width of the scion is 0.8 ~ 65438 0 cm and the length is 3 ~ 5 cm.
The first step of grafting technology is to scion from the tree. After taking off the branches of the year, cut a square with square buds 20 to 25 cm from the ground, then stick the buds on it, wrap them with special film and tie them tightly, and then leave three or four auxiliary leaves on it. Due to the unfavorable factors such as large bleeding, crooked scion and large pith, the survival rate will be improved only if the tools are sharp, the operation is accurate and standardized. Generally, you can tell whether the grafted seedlings are alive or not after seven days. 10 to 15 days, which can be cut. When the new buds grow to seven or eight centimeters, you can take off the plastic sheet, cut the hole from the back with scissors and untie the plastic sheet to make the seedlings grow healthily.
Improving the survival rate of afforestation is an important link in the construction of thin-skinned walnut orchard, and it is also the basic work to achieve strong trees, early eating and high yield. Only by ensuring the planting quality can young trees grow healthily, pass the development stage smoothly and lay a good foundation for increasing production. Only high-quality seedlings can effectively use the cultivation conditions and achieve the goal of more fruits. It is required that the varieties of seedlings are pure, the taproots and lateral roots are complete, there are no pests and diseases, and the resistance is strong. It is best to be a strong seedling of 2-3 years old, with a height of more than one meter, a trunk diameter of not less than one centimeter, and more fibrous roots to ensure survival and robust growth. Generally, the diameter and depth of planting holes are not less than 0.8- 1 m. After the planting hole is dug, the topsoil and soil manure are mixed and filled at the bottom of the hole, and then the seedlings are put in, with the joints facing north, mainly to prevent the wind from blowing, and then the roots are stretched and filled from all sides to the center. Fill the soil in layers steadily, so that the roots are evenly distributed and the soil is flush with the ground. After all-round, steady and steady, make a tree tray, fully irrigate it, and then hang the seedlings when the irrigation is almost complete. The purpose of this is to make the roots look smooth and seal them with soil after water permeates. Seedling planting depth can be slightly greater than the original seedling depth of 5 cm, and then irrigation after seven days of planting.
After filling in the soil, cover the tree pit tightly, generally 80cm square, poke a hole in the middle, then cover it from above, cover it tightly with soil around, and cover the gap in the middle with soil. 15 days later, uncover the plastic film and water it, and then water it every half month to help the seedlings survive. The function of covering plastic film is to raise the ground temperature and protect the injury.
Winter management technology
1. Pruning thin-skinned walnuts in winter is better than pruning in spring. Walnut trees are very strict about pruning time. The best time is to prune after the fruit is harvested and before the leaves turn yellow, and the pruning amount should not be too heavy. The tree shape of thin-skinned walnut is mainly evacuated layered and spindle-shaped. Young trees and trees in the early fruit stage are mainly sparse branches, cross branches and overlapping branches. Control and use the secondary branches, short branches and long branches, and cut off the lower branches, drooping branches and pest branches until the branches in the crown can be evenly distributed, and the pruning principle is that they do not affect each other. The key point of pruning mature fruit trees is to adjust the relationship between growth and fruit. Pruning or thinning the secondary branches that grow vigorously outside the crown, and removing over-dense, cross branches, overlapping branches, sparse branches and pests and diseases; When pruning late-bearing thin-skinned walnuts, we should pay attention to thinning out the thin and weak branches with dense cavities, and if necessary, thinning out some large branches that are too dense, and cultivating fruiting branches in a planned way to maintain high-yield trees. The auxiliary branches are treated according to the principle of being beneficial to the growth of the main lateral branches, and the low branches with vigorous growth are removed.
Second, the trunk is painted white. It is very important to draw the trunk of a small tree. Painting white can prevent longicorn beetles, rot, dry rot, sunburn, frostbite and livestock bites. The formula of plastering is: water 18, salt 1, lime 6, oil 0.3, and sulfur mixture 1.
Third, water and fertilizer management Generally, there are three key periods for watering high-quality thin-skinned walnuts, before freezing, before germination and before fruit expansion. It is especially important to water before freezing. First, watering the fruit after picking can effectively promote the decomposition of base fertilizer, increase the nutrient reserves of trees before wintering, improve the wintering ability, and be conducive to germination and flowering in the next year. Second, it should be carried out after defoliation and before soil freezing to prevent freezing and drought in early spring. The third is to reduce the population base.
The key period of fertilization for thin-skinned walnuts is to apply base fertilizer after autumn, which is generally dominated by farmyard manure or decomposed organic fertilizers such as firewood and straw, which is not lower than the standard of fertilizer per catty 10 catty, so ring or furrow fertilization should be adopted. Topdressing before germination, 0.2~0.5 kg of urea, diammonium phosphate or special fertilizer for fruit trees should be applied to each young tree, and 0.5~ 1.5 kg of fertilizer should be applied to each fruit tree, so the hole fertilization method should be adopted. Appropriate topdressing should also be done during the fruit expansion period.
Problems in cultivation and production
1, the orchard covers an area of poor conditions. The thickness of soil is thin, which can not meet the needs of walnut development; The terrain is too low and the soil moisture is too high in the later stage, which is not conducive to the timely stop of new shoots; Low-lying and leeward, vulnerable to freezing injury.
2. Some orchards lack seedlings and have a large number of mixed seedlings.
3. The varieties are out of order, the growth is uneven, the fruits are uneven, and the differences between plants are too great.
4. Some tree trunks below the surface are frozen or mechanically damaged, resulting in many strip scars, which lead to tree weakness, premature yellowing of leaves and even death of the whole plant.
5. Improper pruning time and methods are not conducive to the growth, development, flowering and fruiting of walnuts.
6. Pest control is unfavorable. The prevention and control of walnut black spot, thorn moth, longicorn beetle, gray leaf spot, dry rot and canker are not timely, which seriously affects the development and fruit of trees.
7. Some walnut orchards are in danger of being eliminated because of replanting and neglect of management.
Specific methods to solve the problem
1. Grafting: The seedlings and inferior varieties in the garden can be grafted again, and the grafting method is close to the teeth. This method is simple and easy. It should be noted that the grafting site is 1 annual robust branch; Scions are used to collect the branches around the crown of high-yield trees, and the harvesting time is in mid-March. After harvesting, it is stored in ditch sand, and grafting can be carried out from late April to early May. This method is fast and the survival rate can reach over 95%. When the bud length is 15 ~ 20 cm, the plastic strip can be untied and taken down, and the live shoots can be tied with columns to avoid wind folding.
2. Soil improvement: For the garden with poor site conditions, fertilizer leakage, water leakage and poor soil, foreign soil and more organic fertilizer can be used to improve the soil to maintain the normal growth and fruit of trees.
3. Prevention of freezing injury: Before winter comes, adobe walls or temporary straw walls can be built in the windward of the west and north of the walnut orchard to keep out the wind. Clear the snow around the root neck and trees in time after snowing to avoid freezing injury.
4. Timely pruning: Walnut trees are very strict about pruning time, and pruning is mainly carried out at the autumnal equinox of the year, and the amount of pruning at a time should not be too heavy, especially for young trees, as long as the branches in the crown can be evenly distributed, and the principle of pruning is not to affect each other. The tree can be divided into two types: scattered layered and free spindle, and the dry height is required to be1~1.2 m. Every year in the middle of September, the overgrown new buds are cut off from the old leaves. Weak branches, dead branches, pests and diseases can also be removed after germination in spring, but the scars on the trunk should be minimized. When trimming, the large incision should be protected by painting immediately.
5. Whitening the trunk: It is very important to whiten the trunk of young trees. Whitening can prevent longicorn beetles, rot, dry rot, sunburn, frostbite and livestock bites. The formula of plastering is: water 18, salt 1, lime 6, oil 0.3, and sulfur mixture 1.
6. Pest control: Before germination in early spring, the whole tree was sprayed with 1 5 Baume sulfur mixture, and from late May to early June, 1 cypermethrin+thiophanate methyl were sprayed respectively. Spray pesticides twice in July and August to prevent moth pests, and pay attention to dry pests in early spring and August. Once found, inject 50 times 1605 into the wormhole with a syringe.