Apricot trees growing under natural conditions are mostly round heads before fruiting, and after several years, they gradually become wide circles or semicircles. This kind of crown has many branches in the inner chamber, but it is chaotic, and the main and lateral branches are not obvious. Although it bears fruit earlier, after a large number of fruits, the tree vigor is easy to weaken, the fruiting parts are easy to move out, the lower part of the crown and the inner chamber are easy to be bald, the fruiting area is reduced, and the yield is reduced. Pruned apricot trees have reasonable tree structure, strong skeleton, large load, full acceptance and utilization of light and heat resources, early fruit utilization and high yield. At present, it is widely used in production, mainly including: natural round head shape, evacuation layered open heart shape, open heart natural shape, fan shape and inverted herringbone shape; Nuts are apricot-shaped, but most of them are naturally clustered.
(1) Natural round head shape (Figure 84) This tree shape is slightly modified according to the natural growth habits of apricot trees.
Fig. 84 Apricot natural round head shape
This tree has no obvious central leadership. After the seedlings are planted, the trunk is fixed at 70 ~ 90 cm from the ground, and 5 ~ 6 main branches are scattered on the trunk. Although there is no obvious trunk, there are 1 main branches extending into the crown, and the rest extend to the periphery. On each main branch, select 1 side branch every 50 ~ 60 cm to make it scattered on both sides of the main branch; Various bearing branch groups are planted on the lateral branches. The location and extension direction of the branch group are not strict, mainly on both sides and under the back of the main branch; Branches planted on the back, as long as they do not grow vigorously, will not affect the growth of fruiting branches such as backbone branches and trees, and can be reduced or thinned when affected.
In the process of shaping this tree, the branches extending at the top can be shortened appropriately to promote the production of branchlets in the middle and lower parts, which is conducive to early fruiting.
This kind of tree is formed under the condition of natural growth with a little manual adjustment. Therefore, the pruning amount is small, the total branch amount is large, the crown is formed quickly, the main branches are evenly distributed, and the fruiting branches are more. Generally, it can be formed in 3 ~ 4 years, and it enters the fruiting period earlier and is prolific.
This kind of tree is suitable for upright varieties, but its disadvantage is that it is prone to baldness in the late stage of crown hole, so attention should be paid to selecting and cultivating preparatory branches as soon as possible when pruning.
(2) The evacuation layering tree (Figure 85) is suitable for dry varieties and apricot orchards with deep soil layers and large plant spacing.
Fig. 85 evacuation layered shape of apricot trees
This kind of tree has obvious central leadership; The height of the trunk is slightly lower than the natural round head shape, generally 50 ~ 60 cm. The whole tree * * * has 6-8 main branches, which are planted in layers on the central leadership trunk: 1 layer 3-4; 2 ~ 3 on the second floor; Layer 3: 1 ~ 2. The interlayer distance between 1 and layer 2 is about 100 cm, and the interlayer distance between layer 2 and layer 3 is 60 ~ 70 cm. The central trunk above 3 layers of main branches can be retained or drained when the density is high, and the spacing between main branches in the layer is not less than 20 ~ 30 cm. On each main branch, select 1 lateral branch every 50 ~ 60 cm, and the lateral branch spacing is 40 ~ 50 cm. Various fruiting branches were cultured on the lateral branches, and the crown formed was semicircular or happy.
Evacuated layered tree with tall crown, obvious middle stem, late tree formation and many main branches. The opening angle of the main branches is large, the illumination condition in the crown is good, the inner chamber is not easy to be empty, there are many fruiting parts, the fruiting period is early, the yield is high, and the economic life of the tree is long. However, if pruning is not properly controlled, it is easy to cause strong upper branches and weak lower branches, and the backbone branches are bald early.
(3) Natural happiness trees are suitable for densely planted apricot orchards in mountainous areas with poor soil conditions.
This kind of tree has no central trunk, and its trunk height is about 50 cm. 3 ~ 4 main branches are evenly and randomly planted on the trunk, and the bottom angle of the main branches is 40 ~ 50 degrees. On both sides and under the back of each main branch, there are several side branches, and the distance between the side branches is about 50 cm. On the other hand, different types of fruiting branches are selected and cultivated according to the space size.
Natural happy tree, small tree body, wide main branch angle, good ventilation and light transmission, strong skeleton, but few branches, slightly lower yield per plant.
(4) Fan-shaped trees and inverted herringbone trees are new dense planting trees in recent years. They are first used for apple trees, then for peach trees and apricot trees. However, due to the uneven growth of apricot branches, it needs to be widely tested and popularized.