Problems and Countermeasures in the Production of Nanguo Pear

I. planting density

The old orchard of Nanguo pear has the advantages of large plant spacing, small number of plants per unit area, high crown, inconvenient management, high production cost, low yield in the early stage and late peak fruit stage. According to the more advanced management methods and techniques, reasonable close planting is advocated. According to the actual situation of Nanguo pear with Arbor rootstock and dwarfing intermediate rootstock, we think that the suitable planting density of Nanguo pear tree with Arbor rootstock is 340m, row spacing 4m and 3335 trees per mu of orchard. This kind of plant row spacing, through the comprehensive use of various pruning measures, can enter the high yield period ahead of time and control the crown width at 3 to 4 meters. If the condition of water and fertilizer is good, once the crown can not be controlled, the method of removing trees and rows can be used in the later stage to gradually increase the row spacing. However, in the establishment of the garden, it is necessary to determine the permanent and temporary plants, using the large crown tree shape for the permanent plant and the small crown tree shape for the temporary plant with early fruit. with the continuous expansion of the crown of the permanent plant, the crown of the temporary plant is gradually reduced to ensure the tree shape and yield of the permanent plant. The suitable planting density of Nanguo pear tree with dwarfing interstock is 1.5 ~ 2 meters, 3 meters between rows and 111 ~ 148 trees per mu. In the mountains with high terrain and large slope, the soil layer is often thin, the management is inconvenient, and the crown is not large. Under the condition that the operation of the orchard is not affected, the planting density can be denser appropriately. In the land with flat terrain and fertile soil, the crown growth is generally tall, and the planting density can be thinner.

II. The problem of shaping and pruning in different periods

1. If the target tree shape of newly planted young trees is not consistent with the planting density, the suitable target tree shape should be redetermined according to the planting density, and the transformation should be carried out according to the tree conditions. For the fruit trees that grow laissez-faire, due to the neglect of pruning, there is no distinction between masters and subordinates in the crown, and some of them grow side by side with 2 or 3 trunks, which seriously affect the growth and fruit of pear trees. When pruning and transformation, first of all, the appropriate target tree shape is selected according to the planting density. Secondly, according to the tree structure, the central stem and the main and lateral branches are selected, the superfluous strong branches and long branches are removed, and the rest of the branches are flattened and released slowly, and the selected branches with small angles are opened in time. For the fruit trees with 2 or 3 trunks growing side by side, one of them is best retained, the other superfluous stems are removed, and then the main and lateral branches are selected and cultivated year by year.

two。 Although the shaping stage of the pear orchard from the early fruit stage to the early stage of bewitching fruit is about to be completed, the unreasonable tree structure still needs to be reformed to form a reasonable skeleton in order to cultivate plump fruiting branches and lay a good tree foundation for future production. Therefore, it is equally important to transform and perfect the tree shape and to cultivate the fruiting branches. It is planned to remove the low branches of the trees with too low trunk and increase the height of the trunk. After the trunk height is raised, the angle of the main branch can be enlarged, which not only improves the lighting, but also facilitates the work under the tree. For the trees with small angle of the main branch and too long branch axis, the key point of pruning is to enlarge the angle of the main branch, and it is better to open the angle in the growing season. At the same time, the branch force of the retracted part should be equal. By pulling branches and retreating, there is a certain space under the tree and between the rows to facilitate the orchard operation. In pulling branches and retraction, we should pay attention to the amount of pruning within one year should not be too large, controlled at 20% to 30%. When sprouting in spring after winter shearing, excess sprouts should be erased to avoid sprouting a large number of ineffective "strips" to consume tree nutrients and worsen ventilation and light transmission conditions.

3. The aged orchard means that the tree is more than 40 years old, because the foundation of shaping and pruning is poor, the tree potential is weak, the fruiting part moves out, the tip of the branch is drooping, the central trunk is not obvious, the number of main branches is large, the angle of the main branch is small, the crown is closed, and the light is poor. The key point of fruit tree pruning in this period is to renew and rejuvenate the branch group, maintain the tree potential, adjust the relationship between growth and fruit, improve ventilation and light transmission conditions, stabilize yield and prolong economic fruiting years.

As a result, for the trees with outward movement, drooping at the apex and weak tree potential, the outer branches are sufficient to form an "umbrella" crown, the middle should be happy, the outer drooping branches should retract, promote the branches in the inner chamber, and gradually reduce the height of the crown. The number of outer branches is small, and several main branches form a "hedgerow" shape, and the drooping branches at the apex should be retracted properly, and the retraction intensity should be slightly greater, so as to stimulate the germination of new branches in the lower part and reduce the height of the crown. After promoting the development of new branches, we should use the method of interception and release to cultivate the branch group downward to make the crown plump again, form three-dimensional results, keep the branch group younger, and maintain the healthy tree potential of the mean.

The trees with inobvious central trunk, many main branches, small angle and closed crown have insufficient number of fruiting branches and few fruiting parts. The key point of pruning is to remove redundant branches and reduce "sticks" in a planned way. At the same time, the suitable fruiting branch group was cultivated according to the size of the space. By reducing the number of large branches and reasonably arranging the groups of large, small, medium and small branches, the problem of ventilation and light transmission can be solved, and the thickness of the leaf curtain layer should not exceed 2 meters. After winter pruning, the distance between the upper and lower main branches is more than 1 meter.

The key point of pruning is to remove the excess "stripes" and solve the problem of ventilation and light transmission. When cutting in winter, remove the extra long branches and thin branches from the inner chamber, and slowly release the full branches. After sprouting in spring, various summer shearing methods were used to control the re-germination of "stripes". When sprouting, wipe off the extra buds on the central stem and trunk at any time. The branches left over during the winter shearing were flattened and released slowly, and then retracted after blooming and fruiting, and then cultured into a branch group. Never use a single winter shearing to transform the tree.