The tree vigor is weak in the young tree stage, weak before the high grafting tree bears fruit, and moderate and stable after the fruit bearing. If there are many fruits, the tree is obviously weak.
Compared with other citrus varieties, the annual growth of shoots is weak, especially in spring, summer and autumn, but the shoots grow well but have thorns. As a result, the new shoots become slender and the leaves are lanceolate. When no fruit is produced, the leaves are large and wavy, and the wings are obvious; As a result, it becomes thinner and the waves disappear.
In view of the above characteristics, plastic trimming is as follows.
(a) Selected trees
It is advisable to have 3~5 main branches in a happy shape, adopt the pruning technique of big branches, cut off too many main branches, pests and diseases, weak branches, too dense branches and strong and straight branches, try to keep auxiliary branches, keep more spring shoots and summer shoots, and keep the tree compact and ventilated; The aging branches and drooping branches that have been bearing fruit for many years should be retracted in time.
(2) Reasonable load
Because the new shoots become thinner and shorter, the leaves become smaller, the tree becomes weaker, and it is easy to bear fruit in the next year, so we should pay attention to the number of fruits and thin them.
From late May to late June, fruit thinning, fruit thinning, insect-infested fruit thinning, small fruit thinning and wind-scarred fruit thinning will make the leaf-fruit ratio 100 ~ 120: 1.
The second fruit thinning is from late July to early August, and the fruit is kept according to the leaf-fruit ratio of 60~80: 1
Trees with weak tree vigor, especially the first fruiting tree and the first fruiting tree after high replacement, can be completely drained to promote the vegetative growth of plants, or the upper part of the crown can be pruned to keep the middle and lower fruits and prevent the next year's fruits.
(3) Pruning of trees in full fruit period
By strengthening fertilizer and water management, reasonable load and moderate results can be achieved, and the relative balance between nutritional growth and reproductive growth can be maintained as much as possible.
At this time, we should do a good job of pruning: first, cut off dense weak branches, dead branches, branches damaged by pests and diseases, cross branches and so on.
Shrink the generated branches to promote vegetative growth.
Second, if the canopy is closed, it is advisable to cut off the top 3~4-year-old branches and open the skylight to improve the lighting conditions in the canopy.
(d) pruning old trees
According to the aging degree, rotation cutting, bare and main branch regeneration pruning were adopted respectively.