2. Prune young trees before fruiting. Young trees generally grow vigorously. In addition to extending branches, they should be pruned as lightly as possible to increase the density of branches, slow down growth and bear fruit early. Generally, only upright branchlets and diseases and insect pests that disturb the tree shape are thinned, and dense branchlets are appropriately thinned. (1) It is very important for young trees to pick the summer and autumn shoots. If the summer and autumn shoots are too long, leaving 8 ~ 10 leaves after self-cutting will promote the second summer and autumn shoots. It has a remarkable effect on varieties with easy growth of summer bamboo shoots such as satsuma, ponkan and lemon. But autumn shoots can't be picked one year before fruiting, otherwise they will. (2) Wipe the buds and put them out. One year before the results, when the buds at the summer and autumn tips are polished, the germination of the lateral buds will be stimulated. Then, after 2-4 days, the newly germinated buds will be removed and germinated, so that the more buds are wiped out, the more buds will be put out. Until the time we require, the buds will be stopped and let out. This is called bud release. The time of filming is very important. Citrus in Guangdong and other places generally put summer shoots and autumn shoots, summer shoots from late May to early June, autumn shoots in late August, summer shoots in early July, autumn shoots from late August to early September and autumn shoots from late July to early August for sweet oranges in Fujian and other places. It is appropriate to choose cloudy days for bamboo shoots, and apply sufficient decomposed organic liquid fertilizer 7 ~ 15 days before bamboo shoots are released. (3) Putting summer shoots to promote autumn shoots. Kumquat in Chongqing grew too vigorously 7-8 years ago, with much stronger summer shoots, fewer autumn shoots and fewer flower buds. One is to erase sporadic summer buds. No fruit trees are released in the summer shoots in late June, but some fruit trees are released in the summer shoots in early July. Then, from the end of July to the beginning of August, the summer shoots were shortened by 65,438+0/3 ~ 65,438+0/2 (20 ~ 25 cm), and each shortened summer shoot could produce 3 ~ 4 autumn shoots in late June, becoming fruiting mother branches. (4) Sparse buds, such as banana orange, ponkan, early-maturing satsuma mandarin, navel orange, etc. Before putting into production, the buds should be thinned, and the vegetative branches should be avoided as much as possible, and the leaves with flowering branches should be reserved. You can also spray gibberellin three times every half month in the first ten days of11~100 ~ 200mg/L, and the flowers will not bloom basically in the second year, so there is no need for artificial thinning.
3. Pruning technology of main varieties: mandarin orange: short crown, sparse branches, thick and long, open, easy to droop, densely clustered branchlets, fruits mostly in the periphery of the crown, and spring shoots, summer shoots and autumn shoots can form fruiting mother branches; But the new shoots are mainly in spring and summer, and the branches are short, generally 10 ~ 20 cm long. June 5438+01~ June 5438+2 for light cutting, take back the long branchlets. For the peripheral clustered branches, the density should be kept sparse, and the weak branches should be kept vigorous. The annual drooping branch is a good fruiting mother branch, and the branches on its back should be retracted and updated 40 cm from the ground after fruiting. After harvesting, the upright branches that affect ventilation and light transmission and are not easy to bear fruit can be thinned out, and the overlapping branches, cross branches, perennial fruiting twigs, shady branches and the like can be thinned out or partially retracted. For mother branches with strong fruiting after fruiting, they should be cut short where new shoots occur, and those with poor growth can be thinned out. Results The branch length is 2.5 cm, and more than 3 leaves can be retained. Bare branches should be thinned.
Ponkan: This variety has erect branches and clusters of new buds, which are easy to form local dense and clustered branches. Spring shoots occur more often, and the mother branches grow well, about 3 ~ 10 cm long. The growth of the main branches is weak, and the bottom angle of the main branches is 40 ~ 50, so the young trees should pull out the branches and open the corners. The summer shoots at the upper part of the crown should be smoothed, and the middle and lower summer shoots should be put on again to prevent the upper summer shoots from being too vigorous. Long branches are not easy to form flower buds, so they should be completely drained except the backbone branches are properly chopped. Dense branches should be weakened and preserved. Young trees begin to bear fruit from the lower branches, and try to keep the lower branches. With the increase of tree age, they gradually turn to the middle and upper branches to bear fruit, and the tree posture is also open, and the fruit on the periphery of the crown is excellent. Adult trees are mainly thinned, and the weak branches and weak fruit mother branches are properly thinned, especially the dense branches in the crown cavity, combined with retraction and regeneration, so that the crown surface forms a large concave and convex shape.
Navel orange: The tree has medium potential, spreading branches, many branches, parthenocarpy, and can bear fruit both inside and outside the crown, with spring shoots and early autumn shoots as the main bearing branches. Results the mother branch is short, and the middle branch with a length of about 5 ~ 10 cm is better. The fruit setting rate of single flower branch with leaves is high. Pruning is mainly thinning. According to the types of new shoots, two measures are taken to promote spring shoots, early autumn shoots and late autumn shoots. Before the leaves of summer shoots turn green, erase the summer shoots or leave 4 ~ 8 leaves for coring to prevent the contradiction between branches and fruits from causing fruit drop. Erase the late autumn buds that are not easy to form flower buds after mid-September. According to the branch and planting position, weaken and retain the clump branches, and remove 1 every 3 days and 2/every 5 days; After drooping, the upright branches retract about 30 ~ 40 cm from the ground. Keep the inner branches well, sparse the upright branches and overlapping branches, cross branches, disease and insect branches on the main branches, especially the branches and leaves with canker disease, and sparse the weak mother branches that bore fruit last year. According to the different tree vigor, flourishing trees should have sparse branches or 4-5 leaves with short nodes, medium branches or weak branches to bear fruit. Therefore, trees should have more weak branches and use moderate branches and strong branches to bear fruit. For the tree of the golden mean, we should appropriately delete the weak branches and the strong branches, and use the golden mean to bear fruit. For weak flourishing trees or strong flourishing branches and few fruits, it is helpful to improve the fruit setting rate by girdling, girdling or twisting branches in late autumn and early winter after flowering. There are too many navel oranges, especially weak trees that bloom early, so we should reduce the amount of flowers. Gibberellin with a concentration of 50 mg/L can be sprayed once in early and late June of 65438+February to reduce flower bud differentiation, and then some leafless flowers and weak branches can be thinned in bud stage to avoid excessive flowering, consumption of nutrients and weakening of tree vigor.
Four Seasons Orange: Each branch can blossom and bear fruit in the same year. When pruning, it is necessary to promote the growth of neat and consistent fruiting mother branches and form a consistent flowering period and maturity period. In order to enjoy the fruits during the Spring Festival in Guangdong, it is advisable to shoot summer shoots and form flower buds from late May to early June, so it is necessary to prune them three times. For the first time, before the spring shoots germinate, cuttings can be carried out on the 2 ~ 3 grade main branches, and the weak trees can reach 1 grade branches, generally leaving 10 ~ 20 cm, which promotes the development of new shoots. Cut off 15 ~ 20 cm when the spring shoots are basically mature for the second time to promote secondary branching; For the third time, the top of the secondary branch is slightly cut to promote flowering and tidy the crown. Make preparations for flower promotion, and the time is roughly from late May to late June, that is, 50 days after the occurrence of secondary branches.