Detailed Explanation of High-Light-Efficiency Tree Shape Renovation Techniques for Kernel Apricot

In regions where kernel apricots are cultivated, we found that due to the influence of traditional habits, most fruit growers either do not prune or prune unreasonably. Each tree has an average of 8 to 10 large branches, the tree shape is chaotic, the proportion of complete flowers is low, the fruiting zone moves outward, the canopy is closed and shaded, and the small fruit-bearing branches in the lower part die prematurely due to shading, resulting in late fruiting, low yield and poor quality of kernel apricots. Therefore, high-light-efficiency tree shape renovation must be carried out to improve quality and efficiency.

High-Light-Efficiency Tree Structure for Kernel Apricot

After several years of exploration and practice, we believe that the high-light-efficiency tree shape for apricot should be the natural open-center form. Its structure and characteristics are as follows: no central leader, trunk height 60 to 80 cm, 4 to 6 main branches growing on the trunk, base angle of main branches 45 to 50 degrees, and fruit-bearing branch groups arranged directly on the main branches. This tree shape has good ventilation and light penetration, high and stable yield, and three-dimensional fruiting.

Key Technical Points for High-Light-Efficiency Tree Shape Renovation

I. Winter Pruning

1. Thinning branches. First, remove the central branch and crossing branches in the inner canopy; second, remove shaded branches, overlapping branches, diseased and pest-infested branches, upright branches on the upper side of branches, and surplus large branches. When removing large branches, do it year by year and in stages, removing 1 to 2 per year, to avoid causing too many wounds in one year and affecting tree vigor. Transform the tree into a natural open-center form over 2 to 3 years. When removing large branches, leave a protective stub, make the pruning and saw cuts flat and smooth, and then apply wound healing agent. In addition, remove dead branches, weak branches and peripheral branches that affect ventilation and light penetration, and thin out branch groups on the upper and lower sides of peripheral branches and inner canopy branches, so that fruit-bearing branch groups are reasonably and evenly distributed on both sides of the main branches.

2. Make full use of water sprouts. As far as possible, retain and utilize the water sprouts and new shoots that emerge from the inner canopy. During the growing season, through continuous pinching or cutting back, allow them to branch and then leave them unpruned to form string-like fruit branches or train them into fruit-bearing branch groups to fill the inner canopy. They can also be shortened year after year to train new main and secondary branches for renewal.

3. Renew and retract fruit-bearing branch groups. In the full bearing period, the degree of shortening should be increased so that all types of branches are continuously rejuvenated, promoting growth and the formation of new branches. After bearing fruit for several years, the trained fruit-bearing branch groups weaken in vigor and the fruiting zone moves outward, so they should be retracted to a vigorous branching point to rejuvenate the branch group and strengthen branch vigor, or retracted to the base for renewal to stimulate new shoots, retrain fruit-bearing branch groups, and maintain a long vigorous fruiting life.

4. Renew string-like fruit branches. After bearing fruit continuously for six or seven years, string-like fruit branches weaken, the short branches decline and fruit production decreases. Light retraction can no longer rejuvenate branch vigor, so they can be retracted again to about 10 cm from the base to stimulate latent buds to sprout long shoots and retrain string-like fruit branches.

II. Summer Pruning

1. Remove sprouts and suckers. After removing large branches, promptly remove the sprouts emerging at the pruning and saw cuts that are in unsuitable positions or too numerous, so as to reduce nutrient consumption and improve ventilation and light penetration in the tree; water sprouts in suitable positions should be trained and fully utilized after renovation.

2. Pinching and shoot tipping. During the growing season, pinch or tip the water sprouts in suitable positions in the inner canopy and the upright moderate-vigor branches on the upper side of branches to stimulate new shoots and train new branch groups. Pinching long fruit branches can control growth, promote nutrient accumulation in the branches, improve flower bud plumpness, increase the proportion of complete flowers, and delay the outward movement of the fruiting zone.

3. Branch bending and thinning. After mid to late May, bend the long shoots other than the extension shoots of the main and secondary branches, especially the long shoots on the upper side of the inner canopy. This can control extension growth and promote flower bud formation in the lower part of the branches. When there is no space, timely thin out water sprouts and overly dense branches.

In addition, high-light-efficiency renovation of kernel apricots must be combined with measures such as strengthening fertilizer and water management and carrying out good disease and pest control, so as to maintain strong vigor and a high-quality, stable-yielding tree.