(1) Controls the height of the tree.
(1) adopting a new tree shape, such as folding fan pruning, weakens the top advantage of the central trunk by bending and folding the main branches of each layer, thus reducing the crown height; Another example is oblique herringbone pruning, which reduces the crown width by reducing the number of main branches and bending the main branches. This tree has only two main branches, one bends to the southeast and the other to the northwest. Branchlets are mainly planted on the main branches, which greatly reduces the height of trees. The above two tree shapes obviously reduce the crown, and the height of the tree can be controlled at 2.5 ~ 3 meters.
(2) Slow cutting leads to excessive short cutting, which leads to vigorous growth of branches and enhanced polarity. However, light cutting and slow release, combined with branch pulling, can also play a role in reducing tree height.
(3) Turn the main valve stem and replace the head. In order to weaken the top advantage of the central trunk, the method of changing the head of the trunk can be adopted to make the central trunk form a small bend and control the height of the tree.
(4) shaping and trimming the shape of the sparse layer of the upper early fruiting crown, changing the upper central trunk into the main head, taking the second and third branches as the leading branches, and bending the original leading branches by one level. In early June, girdling was carried out at the base of the inverted branches, and girdling was carried out again 10 day after the first girdling, which promoted the formation of flower buds and produced a large number of fruits, thus weakening the growth ability of the central trunk and indirectly controlling the height of trees.
(5) timely lowering the head according to the number of main branches or branches required for close planting and shaping, timely lowering the head of the middle trunk not only controls the crown height, but also increases the top light.
(2) Limit the width of hedging
Because of the small spacing between plants, the close-planted orchards with trees and rootstocks often form hedges, which are mostly planted on the north and south sides. Its light source mainly depends on east and west light. If the hedge is too dense, it will inevitably affect the sunlight entering the crown, hinder the photosynthesis of internal leaves, and directly affect the yield and quality of pear trees. The methods to limit the hedging width are:
(1) The tree can be made into a flat crown by using flat pruning methods, such as folding, oblique herringbone pruning and zigzag pruning.
(2) Slow down the peripheral buds. When the crown is formed, the new branches on the periphery should be thinned and not cut short, so that the tree can have good light.
(3) Scaling according to the specified hedging width. When the crown of the tree exceeds the specified hedge width, the super-long branches released slowly for many years will be retracted in the years with many buds, and scaled within the specified range, with a certain width between rows to ensure sufficient illumination on both sides.
(3) adjusting the density of branches
If the technical measures can't keep up, pear orchards planted with tree rootstocks will easily cause branches to grow vigorously, the whole orchard will be closed, the branches at the lower or inner part of the crown will wither, the buds will die, and the fruiting parts will move out. The solution to this problem is not only to limit tree height and hedge width, but also to adjust branch density. The method for adjusting the density of branches is as follows:
① Less main branches are the main skeleton of trees, which can reduce the thickness of leaf curtain layer and easily adjust the density of internal branches.
(2) Reduce the order of backbone branches. Different planting densities have different tree shapes, so the order of backbone branches should be reduced. Some branches have a central trunk, and the main branch has no side branches, which directly bear branches; Some have a central trunk, and the fruiting branches are directly planted on it; Some have no central trunk, and the resulting branches are directly connected to the main branches. With the decrease of the number of main branches, the branch density becomes smaller.
(3) Timely control of erect branches, competitive branches, and competitive branches with strong growth potential and a large number of growing branches are the main harmful branches that disturb the tree shape and close the crown. Buds that are about to develop into competitive branches and back branches should be erased in the spring bud stage. When cutting in summer, some competitive branches and upright branches will be thinned out.
(4) Remove all kinds of bad branches in time. When the crown is too dense, remove too many temporary transition branches and increase oblique illumination. Retract and remove the skirt branches, overlapping branches and drooping floor branches that have been weakened for many years in time to increase the reflected light on the ground.