Weather forecast in Dingzhou City, Hebei Province

Walnut has always been one of people's favorite nuts, and it is also the main export fruit in China. At present, as an ecological and economic dual-purpose tree species, walnut trees are widely used in returning farmland to forests in hills, mountains and plains. However, due to the immature grafting technology, the grafting survival rate is low and the cost of grafted seedlings is high. Below I briefly introduce walnut grafting technology, and friends in need can refer to it!

Grafting technology of walnut tree: 1. Common grafting methods:

1, Splitting method: Split a bite on the rootstock and insert a scion, so it is called Splitting method. Splitting is the main method of branch grafting in spring.

1) rootstock cutting. Saw off the rootstock where the bark is straight and scar-free, smooth the wound with a knife, and then split 1 4-5 cm deep vertical seam in the middle of the rootstock.

2) Cutting the scion. Leave 2-3 buds on the scion, and cut 1 knife on the left and right of the lower part to form a wedge shape. The wedge-shaped outer side of the lower part of the scion is connected with the rootstock cambium. There is no internal connection. The cutting length of the scion is 4-5cm. The cutting surface should be smooth and the angle should be appropriate, so that the rootstock and scion at the interface can be butted from top to bottom.

3) Join. The key is to align the cambium on both sides, and it is best to make the cambium on both sides of the scion face each other. If the two sides cannot be aligned, keep one side of the forming layer aligned. Be careful not to insert all the wounds of the scion into the incision, exposing more than 0.5 cm to facilitate wound healing.

4) dress. For medium or thin rootstocks, insert the scion of 1 into the split (preferably sealed with wax), and then tie the joint with a plastic strip 4 cm wide and 30-40 cm long. When dressing, all cracks, wounds and exposed parts should be bandaged and tied tightly.

2. Double-door budding and single-door budding: When grafting, pry open the bark on both sides of the rootstock incision, just like opening two doors, so it is called double-door budding; Single-door budding is just to pry open the bark on one side of the incision. Other grafting methods are the same. Suitable for grafting varieties that are difficult to survive. After the grafting survives, it can germinate that year.

1) rootstock cutting. Make the length of the bud piece equal to the length of the rootstock incision. Cut the rootstock up and down at the smooth bark with an L-knife, so that the width exceeds the width of the bud appropriately. Then cut the L knife longitudinally in the center to make the incision H-shaped. If it is a single door, cut 1 knife longitudinally on one side of the xylem. Then pry open the bark to form a double door or a single door.

2) Cutting the scion. Carve an L knife around the scion bud and take out the square bud.

3) Join. Put the scion into the incision of the rootstock, and perform double-door budding, that is, cover the left and right sides of the scion bud sheet; Single-door bud, that is, pry open the rootstock skin to cover the scion bud, and the bud should be close to the pried side.

4) dress. Bind the buds with plastic strips with a width of1-1.5cm and a length of 30-40cm to expose the buds and petioles.

3. Square grafting: The buds taken during grafting are square, and a square bark is taken from the rootstock accordingly, so it is called square bud grafting. Square budding contact surface is large, which is suitable for walnuts that are not easy to germinate and germinate easily after grafting.

1) rootstock cutting. When grafting, compare the length of the incision between the rootstock and the scion, and carve the mark with a knife. Then cut a knife against the xylem, up and down, left and right, and then pick out and remove the root bark with the tip of the knife.

2) Join. Put the bud into the rootstock incision so that it is just closed with the rootstock incision. If the scion bud is smaller, it doesn't matter: if the scion bud is too big to insert, it must be cut to make it the right size.

3) dress. Tie the joint tightly with a plastic strip with a width of1-1.5cm and a length of 30-40cm to expose the bud and petiole.

Second, the technical points of grafting for big branches:

1. The quality of scion collection is directly related to the survival rate of grafting. Developed branches or long branches with vigorous growth, full development, small pith, no pests and diseases, and thickness of 1.0- 1.5 cm should be selected. The scion collection time can be from the time when the walnut leaves fall to the time when the sap flows out. The storage of scions depends on the grafting period.

2. The storage period of scions in the middle and late April is long, and the buds are easy to mildew or germinate, so the storage of scions is very important. The optimum storage temperature of walnut scion is -5℃, and the highest storage temperature is not more than 8℃.

3. The temperature of wax-sealed walnut scion is higher than that of other tree species, and the wax-sealed scion should be controlled at 10- 15℃, so that the wax skin of wax-sealed scion is not easy to fall off during grafting.

4. The rootstock should be less than 20 years old, the tree body should be strong, the grafted part should be smooth, and the thickness of the grafted part should be 3- 10 cm.

5. The best grafting period is the time from rootstock germination to the appearance of the first leaf.

6. 2-3 days before rootstock treatment, it is required to drain water from rootstock damage to reduce the impact of bleeding on survival rate.

7. The best grafting method is tongue grafting.

8, two weeks after water control, check whether there is water in the joint, and if there is water, it should be hurt in time.

9. In addition to germination after grafting, the sprouted tillers should be erased in time to prevent nutrient consumption, which is beneficial to the healing of the grafted parts.

Three, the technical points of seedling germination:

1. Grafting time: The best time for budding walnut in Dingzhou is from May 20th to June 20th.

2. scion collection: select the developing branches, cut off the scion and then cut off the leaves from the base of 1.5-2.0 cm. When collecting scions in large quantities, sacks should be prepared, and the harvested scions should be covered with wet sacks at any time to prevent them from losing water.

3. scion storage: it is required to be used now, and the scion should be stored for 3-4 days at most after collection. Storage method: the scion should be tied and placed vertically in a container filled with clear water, and the immersion depth is about 10 cm. Cover the upper part with a wet sack and put it in a cool place. If it is stored for a long time, you must change the water 2-3 times a day. 4. Bud cutting: In the upper part of the scion and the lower part of the petiole, the width is-1, and one knife reaches the xylem, so it is required to cut the phloem, and then cut one knife longitudinally on both sides of the petiole, so that the bud cutting can be easily removed.

5. Open the door of the rootstock: cut a knife horizontally at the top and bottom of the rootstock, the length is the same as the length of the bud, and then cut a knife longitudinally at the outside, and the depth of the knife edge should be cut to the phloem, so as not to hurt the xylem. Then peel the rhizome from the opening with a water knife, and peel off the skin with a width of 0.6-0.8 cm after peeling.

6. Bud insertion: remove the cut bud from the scion and insert it into the opening of the rootstock. Be careful not to rub the buds back and forth on the rhizome to avoid damaging the cambium.

7, binding to bottom-up, binding closely, moderate force.

8. After connecting the cutting anvils, leave two cutting anvils on the bud.

9. After the second anvil shearing for about 10 days, the petiole can fall off. When a few grafted buds germinate, the anvil is cut at 1.5-2 cm.

10, when the binding bud grows to 10 cm, remove the plastic strip. There are many external conditions and internal factors that affect the survival of walnut grafting. When referring to this technical point, we must combine the local site conditions and climate conditions to improve the grafting survival rate.

Four, the matters needing attention when grafting:

1, green branch scions are used for walnut field grafting. It is best to pick the scions nearby and pick them at the same time. If you need to transport or store the scion for a short time, you must do a good job of moisturizing.

2. The grafting site should be selected on the branches below 3 years old. The grafting site is too thick and the cortex is too thick, which affects the survival rate.

3. Grafting larger rootstocks should be reshaped before grafting. Moreover, the buds should be connected on both sides of the branches to facilitate opening, ventilation and light transmission.

4. Choose whole leaf buds or mixed buds for bud connection, and male flower buds cannot be used as scions. Generally, withered buds are used as scions, which cannot germinate that year.

5. The grafting operation should be rapid and the dressing should be strict.

6, pay attention to listen to the weather forecast, try to avoid rain, so as not to affect the survival.

Verb (abbreviation for verb) management after grafting:

1, after grafting: 10 days or so, check the survival situation, the sign of survival is petiole shedding or bud germination, and replant in time if it is not alive.

2. De-bud: De-bud the rootstock to promote germination. Generally, it takes about 1 time to germinate 10 days.

3. Rootstock cutting: After the grafted bud survives, the rootstock can be cut off about 2cm above the grafted bud to stimulate the growth of the grafted bud.

4. Unbinding: When the grafted bud grows to more than 5 cm, it can be unbinding. Unbinding too early or too late will affect growth.

5. Picking: When the grafted buds grow to about 30 cm, pick the heart to ensure safe overwintering.

6. Pest control: such as inchworm, moth and other pests. 2,000 times of prochloraz can be used for pest control.

7. Cold-proof: Walnuts need to be wintered and cold-proof in the year of field grafting. Before the soil freezes, they can be buried underground to prevent cold. If it can't be buried underground, it can be wrapped in plastic film and unearthed or unpacked at the right time in the next spring germination period.