Pruning Jujube Trees in Three Stages Helps Increase Yield

I. Trees in the early fruiting stage. The canopy of the jujube tree has not yet formed, and vegetative growth still predominates, but the yield increases year by year. Pruning at this stage should focus mainly on thinning, renewal pruning, heading back, and training, carried out according to the principle of “four keep, five do not keep.” The “four keep” means: keep the outer jujube heads; keep the jujube heads on the scaffold branches; keep the vigorous, well-filled jujube heads with development potential; and keep the jujube heads that have large numbers of secondary branches and jujube spurs and strong fruiting capacity, so as to achieve the goal of continuously expanding the canopy and increasing yield year by year. The “five do not keep” means: do not keep drooping branches and weak branches, do not keep slender weak oblique branches and overlapping branches, do not keep diseased, pest-infested and dead branches, do not keep improperly positioned and poorly filled water sprouts, and do not keep whorled branches, crossing branches, twin branches and water sprouts. Head back jujube heads that are more than 3 years old and are not serving as extension leaders of main branches, as well as main-branch jujube heads that are no longer being extended. For bare scaffold branches, gradually carry out renewal pruning by cutting back.

II. Jujube trees in the full fruiting stage. The canopy has already formed, growth vigor has weakened, the canopy is basically stable, and fruiting capacity is strong. In the later period, the tips of the scaffold branches gradually bend downward and cross one another, the inner canopy gradually dies off, and the fruiting zone shifts outward. Therefore, pruning should adopt a combination of thinning and cutting back, open up the light path, lead light into the inner canopy, and train inner-canopy branches. Pay attention to the training and renewal of fruiting branch groups to prevent inner branches from dying off and the fruiting zone from shifting outward.

III. Jujube trees in the aging stage. For renewal pruning of aging jujube trees, the pruning method should be determined according to the degree of decline in tree vigor. For trees whose fruiting branch groups have just begun to decline, all aging branch groups can be cut back and thinned during winter pruning. Branch groups that are already incomplete and have very few fruiting base branches should be removed from the base. Other aging branch groups should be cut back by 1/3 to l/2 to concentrate nutrients and stimulate new branch growth. Jujube tree branches and trunks are soft and tend to droop. Drooping scaffold branches can be cut back to raise the branch tip angle and enhance growth vigor. The degree of cutting back is 1/3 or 2/5 of the length of the scaffold branch. For 1- to 3-year-old developing branches sprouting within the canopy, according to the amount of space available, leave several secondary branches and head back to train small and medium-sized branch groups. For aging trees in which most fruiting branch groups have died and the tips of the scaffold branches have begun to die, in addition to heavily thinning out aging, dead and incomplete fruiting branch groups, the degree of cutting back of the entire scaffold branch system (including the central leader) should also be increased. Generally, they should be cut back to 1/3 to 1/2 of the original scaffold branch length, but care should be taken to control the diameter of the saw cut at the cutback site so that it does not exceed 5 cm. For old trees that have undergone renewal pruning, stop bark girdling, reduce fruiting, and strengthen fertilizer and water management to promote vegetative growth of the tree so as to restore tree vigor as quickly as possible. To ensure good results from renewal pruning, aging trees should mostly be renewed all at once. Local renewal carried out alternately by branch system is often unsatisfactory.