On the basis of different stages of natural growth and development, according to the needs of cultivation techniques and economic benefits, Xiaoguan pear tree is divided into four stages, namely, the stage of promoting growth and shaping (1 ~ 3-year-old tree), the stage of promoting fruit and pressing crown (4 ~ 6-year-old tree), the stage of high quality and high yield and the stage of regeneration and rejuvenation. Different pruning techniques were used at different ages, which achieved the economic effect of high and stable yield.
1 promoting growth and formation period
Growth-promoting period refers to pear trees that are 1 ~ 3 years old. The growth characteristics of this period are vigorous growth, long branches, small vertical angle, less early branches and less long branches. The principle of pruning is to promote, increase branches and crown, and open the angle. The task of pruning is to fix the stem, reshape, select and cultivate the backbone branches, and increase the number of branches by short cutting and eye injury, which lays a good foundation for promoting fruit and crown.
Cut at 80 ~ 100 cm from the ground. Choose to cut off 6 ~ 8 full buds; Where there is wind, the incision should be left on the windward side to reduce the wind damage. For varieties with strong branching ability and small branching angle, such as Xuehuali, secondary drying method can be used.
When pruning 1 annual trees, 4 ~ 6 full buds will be left for 1 annual branches above 30cm, only the terminal buds will be cut for branches below 15~30cm, and branches below 15 ~ 30cm will not be cut. The pruning of 2-year-old young trees is still mainly short-cut. When the extension branch of the central trunk is more than 50cm, 4 ~ 6 full buds will be cut off, and 3 ~ 6 buds will be injured; Only the terminal buds of 30 ~ 50 cm are cut off; No splicing below 30cm. Other 1 annual branches over 50cm are cut off, leaving 3 ~ 5 full buds; Cut off 2-3 complete buds of 30-50 cm leaves; Do not cut those below 30cm, make full use of the growth advantages of terminal buds to promote the growth of strong branches.
When pruning 3-year-old young trees, they should be shortened according to the number of new branches and the growth intensity. The cutting method of the extension branch of the central trunk is the same as that of the 2-year-old young tree, but at this time, the central trunk has reached the predetermined height, and the 1 ~ 2 buds under the cutting mouth can be left in the inter-row direction in a short time, making full use of the space and light conditions. At this time, the diameter of the middle part of the whole tree is greater than 1cm, and the number of branches with a length greater than 100cm should reach the square meter of the nutrient area occupied by the tree. This requirement is the basic condition for pear trees to switch to crown pressing stage with fruit under different densities. If the number of plants per square meter of nutrient area is more than 0.5, it can be cut and put according to 1: 1, that is, one plant is cut short and one plant is put long. If the number of such branches per square meter of nutrient area is less than 0.5, it can be cut and released at the ratio of 2: 1, that is, two branches are cut short and one branch is extended 1. Other branches 1 year less than 1m, all of which are extended and not cut. After three years of pruning, the skeleton of the tree was basically formed, and the long branches were initially equipped, so that the growing, flowering and fruiting branches were evenly distributed in the crown, which laid the foundation for promoting fruit and pressing the crown.
Because the overall growth rate of young trees of Xuehuali pear is slower than that of Yali pear, it is more difficult to bloom. Generally speaking, the formation of Yali pear is 1 ~ 2 years later, so some flowering measures are often needed. The branch angle of Xuehuali pear is small, which can be adjusted by anti-bow bending to prevent splitting.
2. The period of promoting fruit and pressing crown
The age of the tree in this period is 4 ~ 6 years, the crown is not open, the tree is thick and leafy; In the later period, the tree softened and began to bear many fruits. The principle of pruning in this issue is to give priority to enlargement, combining enlargement with reduction. The task of pruning is to promote flowering and fruiting, slow down the crown, fix the branch group, and lay the foundation for high quality and high yield.
The pruning of the robust branch group is mainly 1 annual branches above 1m, and the vertical angle is small, generally within 30, so the angle is not easy to be pressed open after the result. When such branches grow into flowers, they can be cut off and pressed on the wheel marks, leaving 2-3 short branches and shrinking again. This pruning measure can inhibit the thickening growth of branches, and the cut short branches can promote the long branches. If the long flowers still don't open after blooming, they can shrink again, forming a situation of single branch renewal combined with scraping.
Pruning of stronger branches This kind of branches grow stronger and have a certain inclination angle, and the fruit is easy to be pressed open after bearing. Generally, it takes 2 years to cut off the top, so that the upper and lower parts of a branch member can rotate to produce results, so as to open the angle.
Pruning of general branches This kind of branches are mostly composed of 1 annual branches, about 50cm long, with a vertical angle of 45 ~ 60, and medium growth. After 1 year, such branches can be elongated at the tip to cut wheel marks, stabilize the length of branches, and make a single branch bear fruit every other year, and then bear fruit every year with the formation of bearing branches.
The pruning branches in the weak branch group are weak, and the vertical angle is greater than 60. When pruning, the stronger branches can be cut off and pressed on the wheel marks, and the weaker branches will be raised and shrunk, that is, the long branches will be pulled out and put into the long branches, and the drooping branches will be shrunk first, then shrunk and put in, so as to cultivate a stronger branch group.
1 annual branches are pruned, except for the extension branches of each main branch, the other 1 annual branches are not pruned when they are long, and they are too dense and sparse. Small angles should be tied into a reverse bow and bent to the main shaft to reduce the tree potential and increase the load. In addition, for the branches with small bottom angle and waist angle and weak crown, the angle should be increased by supporting, pulling or opening the back branches.
For varieties that are not easy to bloom, such as Sydney, it usually takes two years to see the flowers after putting long branches, so as not to shrink without flowering. Strong 1 annual flowering branches generally need to be girdled or girdled at the base of the branch axis to improve the flowering rate.
3 High quality and high yield period
At this stage, the tree body has been controlled within a certain range, and the large and medium-sized long-axis branches have been basically fixed, with the number ranging from 10 to 12. The principle of pruning is based on shrinkage, combined with scaling, maintaining tree potential and replacing results. The task of pruning is to remove or retract the overlord branch group, renew and rejuvenate the weak branch group, finely prune the branch group, maintain the flower position and appropriate amount, improve the fruit quality and prolong the high-quality and high-yield period.
The pruning of large and medium-sized long-axis branches is mainly to adjust the branch potential and control the length. The more backward it is, the stronger it is, leaving weak buds and weak branches as the head control top advantage. The weak should remain strong and strengthen their own advantages. The side branch with large branch spread should be retracted in time to maintain the uniaxial advantage. The overlord plants with small angle and strong growth should be thinned or reduced again to improve the illumination.
Generally speaking, the pruning measures of weak branches are to put them first, then shrink them, and then sparse them, so as to enhance the branch potential and sparse them. Fruit branches should be carefully pruned in line with the principle of staying far and near, weakening and staying strong, and leaving edges on the top. Pay attention to the use of long branches, which can generally be released slowly in situ, or slowly in turn, or cut first and then released, in order to cultivate into fruiting branches.
The fruiting platform of Xuehua pear has poor branching ability, and it is easy to extend a single fruiting platform or appear fruitless platform phenomenon. When pruning, pay attention to cutting or retracting the branches of the fruit table, promote branching, and prevent the back from being too thin and too thick and bald.
4 Renewal and revival period
After entering the regeneration and rejuvenation period, the tree vigor is weakened year by year, with low yield and poor quality. Pruning is mainly based on complex shrinkage, combining cutting and putting. According to the principle that strong trees are light, weak trees are light, big branches are light, and small branches are light, the branch axis of strong branch group is reduced by about 1/3, that of weak branch group is reduced by about 1/2, and the components of big and middle branches shrink in two years. After rejuvenation, release all the annual branches of/kloc-0, and make full use of the long branches. If the trees can be restored to their original appearance, they can be pruned according to the high quality and high yield period. Of course, different varieties, different climates, different soils and different density methods are also different.