Winter pruning techniques of pear trees in southern scaffolding

Winter pruning techniques of pear trees in southern scaffolding

Pear tree scaffolding cultivation is a kind of pear tree cultivation method supported by flat shed surface made of cement column (or steel pipe), steel wire and other materials. Since this cultivation method was introduced into China from Japan in the 1990s, it has been popularized and applied in both north and south pear producing areas in China [1-3]. The original intention of pear tree scaffolding cultivation is Fangfeng [4], but the research shows that the scaffolding cultivation has obvious advantages in improving fruit quality [Jishan Huayao]. The climate of pear producing areas in southern China is high temperature and humidity, scaffolding cultivation is beneficial to improve the ventilation and light transmission conditions of trees, good fruit quality and convenient for sightseeing picking, which has become a new bright spot of pear industry technology in China [8].

1 Tree shape and growth and fruiting characteristics of scaffolding pear

The tree shape characteristics of scaffolding pear are as follows: no central trunk, happy shape, trunk height 110-120 cm, generally 2-3 main branches. at present, most of the scaffolding pear orchards built are short trunk and three main branches, but the tree structure of two main branches and high trunk is simplified and easy to operate, which is the development trend of scaffolding tree in our country in the future. The growth and fruiting characteristics of pear trees in scaffolding are as follows: (1) the main branches and fruit branches are horizontal after they are put on the shelf, and the top dominance of the main branches is weakened, and the base is easy to grow branches; (2) the branches can be freely induced to fill the space and have higher early yield; (3) they also have better branching ability without "sprouting buds" or smearing "branching agents", and the fruiting branches are easy to renew after aging. (4) the pear trees in the scaffolding are ventilated and transparent, the fruit is naturally drooping, neatly consistent, and the rate of high quality fruit is high; (5) the branches are tied to the shelf surface, and the "wind damage" fruit drop before harvest is light.

2 main techniques for winter shaping and pruning of scaffolding pear trees

2.1 Winter shaping of young scaffolding pear trees

The pruning of pear trees in the scaffolding is simpler than that of the traditional evacuation layering, the fixed stem height of the seedlings is 1-1.2 m, and there are at least 4-5 full buds under the cut. In the first winter, 2 or 3 strong branches were selected from the cutting buds as the main branches, truncated at the lateral buds at the apex, and properly induced upward when the extended branches were sagging. In the following winter, the competitive branches at the apex of the main branches, the upper dorsal branches and the branches growing on the trunk were all removed, and the extended branches of the main branches kept growing upward. In the third winter, the main branches exceeding the shelf surface were horizontally tied to the flat shelf surface, and the apex was induced to grow upward; the upper dorsal branch on the main branch was removed, and the fruiting branch group was directly selected on the main branch, and the branches forming flower buds or short fruit branches were flattened and tied to the shelf surface. By the winter of the third year, the scaffolding pear trees basically took shape.

2.2 Winter pruning of adult scaffolding pear trees

It mainly includes extending the main branch, the upper dorsal branch, the fruiting branch group, pruning the auxiliary branches and binding the branches to the shelf.

The main results are as follows: (1) pruning of main branches: under the condition of high temperature and heavy rain in the south, pear branches grow for a long time, shoot many times, and the apex is not full, so it should be cut at least to the full part when it is cut short. The interception length depends on the growth of the branch, the short cut degree of the extended branch is slightly lighter when the growth is prosperous, the growth potential should be properly heavy, but the short cut degree should not be too heavy, and the interception length should not be less than 30 cm, otherwise the branch will be difficult to flatten out when it is on the shelf. If the growth of the extended branch is too weak, you can choose the strong branch at the back to "change the head". It is appropriate to select lateral buds so that the branches can be flattened and put on the shelf. The elongated branches of 1-year-old main branches should be induced upward in oblique shape, and should not be flattened when pruning in winter of that year.

(2) pruning of the upper branch on the back of the main branch: the thinning of the upper branch on the back of the main branch should depend on the number of branches near the branch. When there are many nearby branches and there is no extension space, when the upper branch of the main branch is removed, the saw blade should be close to the main branch, enlarge the sawing surface, thoroughly remove the hidden buds at the base of the overgrown branches on the back, and reduce the artificial wiping of hidden buds in summer after the emergence of hidden buds; when there is room for extension of branches nearby, the outer hidden buds can be kept for pruning.

(3) selection of auxiliary branches and cultivation of fruiting branches: when the growth of branches on the shelf is small, 2 or 3 weak branches should be properly retained as auxiliary branches, which is very important for the shaping and pruning of young scaffolding pear trees. When there is a large amount of branches and leaves on the shelf surface, no branches will be left under the shelf. Results the culture method of the branch group was relatively simple. Generally, the branch from the lower part of the cross section of the main branch was selected as the uniaxial fruiting branch group, and the strong new shoots were pulled into an angle of 45 °after stopping growing in the same year, in order to form axillary flower buds and flatten the fruit in the winter of the same year. The branches with weak growth potential were cut heavy and short in winter, and then let them blossom and flatten out on the shelf after taking out the longer branches.

(4) pruning of the fruiting branch group: remove all branches on the fruiting branch group during winter pruning, avoid using weaker branch results, and maintain the uniaxial extension of the fruiting branch group; the stronger branches at the top of the fruiting branch group are selected for shortening, so that the fruiting branch group extends slowly at the same time of fruiting; the fruiting branch group is generally not retracted and pruned from the base when the number of flower buds is small and bald appears, and the general fruiting life is about 4 years. Results the prepared branches were cultured from 1 to 2 years before senescence in the branch group, and the prepared branches were thinned from the base when they could fill the shelf space. In the larger part of the space, when the growth of the preparatory branch is weak, it should be re-cut to promote its strong branch, and then slowly put into flowers the next year, so that it can occupy a larger shelf space after leveling.

(5) binding of branches to the shelf: southern sand pear varieties are easy to form flowers, and branches with long fruit branches (with axillary flower buds) are formed in that year, which can be tied to the shelf surface in the winter of the same year; branches that are not flowering or with a small number of flowers in that year are slowly released or lightly cut, they are induced to the shelf surface at about 45 °, and the short fruit branches are formed in the coming year and then pulled flat on the shelf. The bound branches are in the shape of "8" and should not be too tight, so as to avoid "constriction" with the thickening of the branches.

3 matching technology

1. If the diameter of the wound is more than 2 cm after pruning in winter, the wound protective agent should be applied.

2. In spring, the sprouting on the back and the sprouting on the shearing mouth of the main branch should be wiped out in time. The upper part of the back about 20 cm from the branching point of the main branch is easy to grow branches, so attention should be paid to erase it. The upper dorsal branches other than the length of the main branch 1 beat 2 can be retained properly when the growth of the extended branch is not affected.

3. The degree of elongated branch pruning is different in different pear varieties. Varieties with weak growth potential, such as Huali No.2, should be re-cut properly, while varieties with strong growth potential, such as Cuiguan, should be cut lightly.

4. Scaffolding pear trees have higher requirements for fertilizer and water, so fertilizer and water management should be strengthened. During the establishment of the garden, heavy application of organic fertilizer is required, and the application of organic fertilizer is more than 2 tons in 667 m2. The available nitrogen fertilizer was applied once a month in the peak growing season of young trees (April to July). Adult trees should be re-applied organic fertilizer in autumn to achieve "jin fruit jin fertilizer", before sprouting and after flowering appropriate topdressing according to the situation of the tree.