In the young tree stage, due to the need of plastic surgery, buds should be carved where long branches are needed to cultivate the main branches. Pay attention to the following three points: first, the time of bud carving should be early (March 1 to March10); Second, the distance from the incision to the bud should be less than1cm; Third, the incision should reach the xylem. In order to ensure that the hair grows long branches, in the budding period from early March to early April, a small bamboo stick can be used to pick out the hair branch paste with the size of a small grain of rice and apply it to the bud end, and each gram of medicine can be applied to 10 ~ 15 buds.
(2) Delayed pruning
Young flourishing trees with difficulty in flowering, low germination rate and low branching rate can be pruned later. In order to alleviate the growth potential, improve the germination rate and promote the formation of short branches and flower buds, pruning can be postponed until after germination and before flowering without pruning in winter. The method of post-cutting is exactly the same as that of conventional winter cutting.
(3) Opening angle of spring
When the sap begins to flow and the branches become soft, the opening angle can be opened. It is worth noting that the opening angle should control the germination of back buds. After opening the corner, knock on the back of the branch with scissors first. Leave 1 bud every 20 ~ 30 cm after germination, and smooth the rest.
(4) cutting again before flowering.
It is carried out at the beginning of April before flowering, and the main task of re-cutting is to adjust the flower bud retention. According to the ratio of 4 ~ 5 ∶ 1 (leaf bud ∶ flower bud), flower buds are left in the early fruit stage, and the flower buds in the full fruit stage can account for 25%. When cutting again, we should first remove the weak flower buds with poor top development, and then remove some short branch flower buds. When cutting again, we should follow the principle of "Eucalyptus fixed production and branch burden" and master the principle of keeping more strong branches and more big branches.
(5) Bud smearing
Before sprouting in spring, the extra buds are wiped from the base. Mainly erase excessive buds on the back of cutting, sawing and pulling branches. Choose a bud on the back every 20 ~ 30cm, and wipe off the rest as soon as possible. For the extension head of the main branch and the central trunk, choose a bud with strong growth and good orientation as the extension head, and erase other competitive buds in time, which can save nutrition and adjust the growth force. For sawn timber and shears, paclobutrazol can also be applied 20 times to prevent them from producing clumped branches.
(6) Pick the core and cut the tip
In the middle and late May, removing the growth point of new flourishing branches or leaving about 15 cm is beneficial to promoting branches and cultivating branches, and at the same time can slow down the growth potential of original flourishing branches. Another function of coring and pruning is to ensure that the main branches cultivated in that year are short on the top and long on the bottom, and to core the main branches with vigorous growth at the top, so as to achieve the purpose of restraining the top and promoting the bottom.
(7) girdling (cutting) and winding
The main purpose is to promote flower bud differentiation, so as to bear fruit and yield early. In addition, it also has the functions of inhibiting vigorous growth, improving fruit setting rate and cultivating regenerated branches. Different uses, different periods of use. Trunk girdling should be carried out at a place 20 cm above the ground, and the girdling width is110 ~1/8 of the trunk diameter. It should be sunny when girdling, and it is best to wrap it with plastic film lined with opaque paper after girdling to facilitate healing and prevent infection. The girdling of the main branch or the auxiliary branch is carried out at a smooth place about 5 cm away from the main branch, and its width is also110 ~1/8 of its diameter. After girdling, 0.3% ~ 0.5% urea should be sprayed in time to avoid yellowing or fading of leaves.
Because girdling has a great influence on trees, girdling of main branches should be advocated. Varieties sensitive to girdling reaction can only be girdled or twisted. Ring cutting is the first ring cutting on the main branch 5 cm away from the main branch, and the second and third ring cutting every 10 ~ 15 days. A distance of about 10 cm is maintained between two adjacent annular incisions. The number of girdling cycles depends on the growth of the tree. If you can control the length and promote flowers 1 time, you don't need a second girdling, otherwise you need a second girdling, but at most three girdling. After girdling, 20 times of paclobutrazol can be applied to the cutting mouth, which will inhibit the flourishing growth and promote flowering better.
(8) Sparse branches
Through slow release, bud carving, girdling (cutting) and other measures, a large number of new shoots are cultivated, which often leads to canopy. Therefore, some dense branches, erect branches, overlapping branches, cross branches and competitive branches with elongated main branches should be pruned in summer and thinned in time from mid-June.
(9) Opening angle of autumn
The opening angle of main branch and auxiliary branch is one of the important indexes of high quality and high yield trees. Opening angle can enlarge crown, slow down growth, improve lighting conditions, facilitate nutrient accumulation, promote short branch development, promote flower bud differentiation and increase early yield.
It is better to open the angle sooner than later, because the earlier the angle is opened, the softer the branches are and the easier it is to operate. Therefore, from the second autumn after planting, it is necessary to use methods such as pulling branches to open corners. When opening the angle, it is required that the angled branches reach a certain length. Generally, the length of the lower branch is about 1 m, and the upper branch is about 70 ~ 80 cm. The best time for opening angle is autumn. At this time, the buds are full and full, and there are no leafy stripes on the back. However, it is easy to run back in the open corner in spring, and summer management measures such as bud wiping, twisting branches and bare branches must be supplemented, otherwise new shoots will flourish on the back, and it is difficult to achieve the purpose of delaying growth and promoting short branches.
The angle varies with varieties, rootstocks, trees, branches, growth intensity and site conditions. Generally, the crown is sparse, the base angle of the main branch is 70 ~ 80, and the waist angle and sharp angle gradually rise. The spindle-shaped main branch has a base angle of 80 ~ 90, which is naturally horizontal. The angle between the side branch and the auxiliary branch is greater than that of the main branch. In order to keep the crown balance, the branch bottom angle with large growth should be larger than that with small growth. The angle of plain land with fertile soil and rich water resources is larger, and that of hilly land is smaller.
Opening angle methods include pulling branches, falling branches, supporting branches and so on. Opening angle is the key technology of high quality and high yield. When operating, it must be "no drilling, no burying, no bending, no turning, and a straight line before and after". Before the formation of young trees, we should insist on opening the angle every year to balance the growth of trees up and down, inside and outside. Only the lower branch is inclined, and the upper branch is not inclined, which is easy to cause the upper branch to be big and the lower branch to be small, and the upper branch to be strong and the lower branch to be weak, which is not conducive to high and stable yield.
(10) winter pruning
After defoliation, the tree will sprout or bloom in the next year, which is the continuation of annual pruning, accounting for more than 60% of the annual pruning. Pruning methods mainly include short cutting, retraction, dewatering and slow release.
Because the nutrients in the tree body, leaves and branches before defoliation flow back to the trunk branches and roots of the tree body, the tree body stores enough nutrients, and after the aboveground part is pruned, the amount of branches and buds of the tree body decreases, which can ensure the nutrient supply of the branches and buds retained by the tree body, thus promoting the growth of new shoots of the tree body. The greater the amount of tree pruning in winter, the more obvious this promotion effect is. Pruning in winter can cut off some flower buds, thus adjusting the yield of trees. In addition, it can also adjust the structure of trees and improve the lighting conditions and fruit quality in the growing season of trees.