Pruning of high cluster blueberries: ① Pruning of young trees. In this period, flower buds are mainly removed, with the purpose of expanding the crown, increasing the number of branches and promoting the development of roots. In the spring of the second and third years after planting, the weak branches become thinner, and in the third and fourth years, the crown is still mainly enlarged, but it can bear medium fruit. Generally, the plant yield should be controlled below 1 kg in the third year, with strong branches as the main fruit. ② Pruning of adult trees. At this time, pruning is mainly to control the height of the tree and improve the lighting conditions, mainly to thin branches, and to thin out branches that are too dense, too thin, branches that are damaged by diseases and insect pests and roots. The root activity is stronger than that of open varieties when thinning branches; Vertical varieties go to the center to dry, open the skylight and leave the middle branches. The best fruiting age of big branches is 5 ~ 6 years old, so they should be retracted and updated in time. Weak branches erase flower buds and make them stronger. Adult trees have a lot of flowers, so some buds need to be cut off. Generally, each strong branch leaves 2 ~ 3 flower buds. ③ Regeneration of ancient trees. After planting for about 25 years, the aboveground part of the tree has become old, and the whole tree needs to be updated, that is, all the aboveground parts are sawed off close to the ground and new branches sprout from the base.
Pruning of shrub blueberries: ① fire scissors. That is, during the dormancy period, all the aboveground parts are burned, and new branches germinate again, forming flower buds in the same year and flowering and fruiting in the next year. After that, it will be cut by fire every two years, and it has always maintained vigorous branches. (2) stubble pruning. Before germination in early spring, the aboveground part should be leveled and sawed off from the base of the plant, and the sawed branches should be left in the orchard, which can play a role in covering soil and improving organic matter.
How to prune blueberries
I. Pruning principle
The general principle of pruning is to keep branches strong, buds strong and trees strong, to achieve the best quality rather than the highest yield, and to prevent excessive fruit. Pruning of blueberry often leads to a decline in yield, but the weight of single fruit increases, the quality of fruit improves, the maturity advances and the commodity value increases. When pruning, it is necessary to prevent overweight and ensure a certain yield. The degree of pruning depends on the purpose of the fruit. If it is used for processing, the fruit size can be good, and the pruning should be light to improve the yield. If it is fresh fruit sales, pruning should be heavy to improve the value of goods.
Second, know the flower bud: The flower bud of blueberry is planted in the upper part of the fruiting branch, generally from the top to 3 ~ 10 nodes, and the varieties with strong flower bud forming ability can reach more than 15 nodes.
The main pruning methods of blueberries are leveling stubble, shrinking in, thinning branches, cutting flower buds, thinning flowers and thinning fruits, and different pruning methods have different effects. Which method should be adopted depends on the age of the tree, the number of branches and the number of flower buds. In the process of pruning, all kinds of methods should be used together to achieve the best pruning effect.
Third, prune small trees.
Young trees will have flower buds 1 ~ 2 years after planting, but if they blossom and bear fruit, they will inhibit vegetative growth. The young tree period is the period of constructing tree nutrition area, and the key point of cultivation management is to promote root development, expand crown and increase the number of branches, so the pruning of young trees is mainly to remove flower buds. In the spring of the second and third years after planting, the weak branches should be thinned, and in the third and fourth years, crown expansion is the main method, but moderate results can be achieved. Generally, the plant yield in the third year should be controlled below 1 kg.
65438+ 0 ~ 2 years after planting: thinning all weak branches and drooping branches (thinning from the base), thinning all transverse branches and thinning all old branches, selecting 2 ~ 3 robust annual base branches, and removing all flower buds by cutting short or rolling out.
3 ~ 4 years after planting: all slender branches and drooping branches (sparse from the base), all transverse branches, dead branches and dead branches are sparse, and there should be 3 ~ 5 strong base branches in the parts where branches over three years old shrink to strong branches. The result may be moderate. Based on the results of strong branches, generally, 50 ~ 100 strong flower buds are cut off for 3-year-old trees according to the growth potential of the trees, and the yield is controlled at about 0.5kg. For 4-year-old trees, 100 ~ 150 flower buds are selected and the yield is controlled at about 1kg.
Four, the principles and methods of pruning of adult trees
After entering adulthood, the crown of the plant is relatively high and the cavity is easy to close. At this time, pruning is mainly to control the height of the tree and improve the lighting conditions. Pruning is mainly based on thinning branches, thinning out over-dense branches, oblique branches, weak branches, pests and diseases, and the tillers and old branches produced by the root system shrink and update. When the tree grows wider, the weak branches are removed and the strong branches are left; Vertical varieties, remove the central trunk, open the skylight, and leave the middle branches. Branches over three years old follow the principle of 6 thinning 1, thinning from the base. The best fruiting age of big fruit branches is 5 ~ 6 years, and after this year, it will be recovered and updated. Fragile branches can be pruned with flower buds to make them stronger.
There are mainly two incorrect pruning methods in blueberry tree production. ① Applying the pruning methods of other fruit trees, the annual branches with medium or slightly strong growth were wrongly pruned, and the result of this pruning was to remove most or all of the high-quality flower buds on the medium or strong branches. Many slender buds germinate under the cutting opening, and the branches are arranged in disorder, especially when they are cut short on the same plane, which eventually leads to scattered nutrition supply and poor ventilation and light transmission. (2) Incorrect coring of new shoots, especially for all medium-growing new shoots, leads to the germination of many delicate branches, which not only affects ventilation and light transmission, but also seriously affects the differentiation of flower buds on the branches and affects the quality and yield of fruits.