After pruning young fruit trees, because the total number of branches and buds has decreased, the leaves left behind can get more storage nutrition; Pruning reduces the amount of branches and leaves on the ground, temporarily changes the natural balance between the ground and underground, and temporarily improves water and mineral nutrition; Pruning improves the ventilation and light transmission conditions inside and outside the crown, improves the photosynthetic efficiency of leaves and improves the nutritional level of local branches and buds, thus enhancing the growth of local branches and buds. These are the partial promotion of pruning to fruit trees. However, this promotion will weaken with the increase of tree age and the weakening of overall growth, and the growth of trees can also be weakened if the comprehensive pruning technology is not used properly.
At the same time, pruning reduces the number of branches and leaves, reduces the total leaf area of the whole tree, and temporarily reduces the total photosynthetic products. Therefore, the growth of aboveground and underground parts is temporarily inhibited, and the total growth of trees is weakened, which is the overall inhibition of pruning. If all the branches are cut short year after year, it will not only reduce the total number of branches and leaves of the whole tree, but also stimulate the growth of local new shoots, make nutrient growth too vigorous, consume too much nutrients and reduce accumulation, which is not conducive to reproductive growth, thus affecting the formation of flower buds and delaying the fruiting period. Therefore, young trees should not be re-cut, and appropriate light cutting is an effective measure to bear fruit and yield early.
The promoting effect of pruning on bud cutting of mature fruit trees decreases with the increase of tree age. However, because the amount of flower buds is reduced during pruning, the nutrition of the tree is preserved, so it can promote the vegetative growth of the tree. If the pruning degree is appropriate, the relationship between growth and fruit can be gradually balanced, thus promoting the growth and development of trees.
When the fruit tree enters the aging stage, some aging branches and redundant flower buds are removed by updating and pruning to reduce consumption, improve the nutritional status of the tree, reduce centrifugal growth, rejuvenate the tree and delay aging. If we can cooperate with fertilizer and water management and comprehensive disease prevention and insect prevention, the effect of renewal and rejuvenation will be more obvious.
In different age stages of fruit trees, pruning has different effects on local promotion and overall inhibition. In the annual cycle, different pruning periods have different reactions after pruning. Pruning in growth period has no obvious promotion effect on local parts, but it has great inhibition effect on the whole; Pruning in dormant period can obviously promote the local area, but the overall inhibition is small; Pruning in the early growth stage, such as pruning before flowering, has a greater inhibitory effect than pruning in the late growth stage. Therefore, in production, only trees with excessive nutrient growth, few flowers and many fruits will be felled before flowering, and they are not suitable for perennial.
Thinning can improve ventilation and light transmission conditions, make fruits well colored, and promote the growth of branches below thinning; However, it has obvious inhibitory effect on the branches above thinning, and more nutrients are taken away by the thinning branches. According to the analysis, after pruning in winter, the amount of nitrogen, phosphorus and potassium taken away from the branches of 20-year-old Yali pear trees per hectare is 45.0 kg, 65,438+03.05 kg and 37.5 kg respectively. When pruning in winter, the wounds caused by the loosening of large branches not only weaken the growth of trees, but also easily lead to pests and diseases or rot. Therefore, useless branches should be erased in time when they just germinate, or thinned in summer to reduce nutrient consumption.
Shrinkage can enhance the growth potential of pruning itself and increase the opening angle of pruning, but it also weakens the total growth of pruning. If the growth is too strong, it will also affect flowering. Due to the size of the incision, the thickness of the branch and the distance between the incision and the contracted branch, the strength of this dual function is usually different. When the incision is small, the branches are thick, and the incision is far from the cutting bud, the effect of strengthening cutting branches is stronger, and vice versa.
The same is true of girdling and girdling, which can obviously weaken the growth and promote the flowering of girdling or above branches; For the branches below girdling or girdling, it can promote the growth and branches.
Proper pruning degree can ensure the formation of a certain size crown, which is convenient for management and beneficial to increase production; However, if the pruning is too heavy, the tree body is short and the crown is small, which is easy to manage, but it is not conducive to increasing production. At the same time, excessive pruning also has some adverse effects, such as delaying the fruiting period and shortening the life of fruit trees.