1. There is generally a special period to be avoided in walnut pruning and shaping, that is, the bleeding period. The reason why walnut pruning is different from other fruit trees is that it is easy to hurt walnut trees because of bleeding;
2. During the period from defoliation to flowering in the following year, when walnut is pruned, rubbed and lacerated, a certain amount of transparent liquid will flow out from the wound, which is called exudation, and this phenomenon is called bleeding;
Walnut has large catheter, large root pressure and large bleeding. Its blood contains a lot of soluble sugar, nitrogen, mineral elements and various amino acids, as well as a small amount of phenols and juglone. Excessive bleeding and loss of nutrients make trees weak and even branches die.
3. Hemorrhage usually begins at the beginning of 165438+ 10, but the amount is very small. By the middle and late of 165438+ 10, with the pouring of frozen water, the amount of bleeding increased sharply and reached a peak. Then the bleeding gradually decreased. From the end of February to the middle of March, there was little bleeding. Then bleeding began to appear again and gradually increased, reaching the second peak from the end of March to April. After that, with the germination and growth, the bleeding gradually decreased;
4. During the walnut ring cutting, avoid the bleeding peak. There are mainly two periods. One is during the winter dormancy period. Although there will be bleeding at this time, the components of bleeding are almost all water and a very small amount of minerals. If we avoid the bleeding peak, it will not have much impact on the tree. Another period is May, which is also a good period for exploitation.
Extended data:
The function of ring cutting of walnut tree;
1, the purpose is to block the transportation of stripped (cut) branches from top to bottom, so as to regulate the growth of branches above the stripped part, promote flower bud differentiation, improve fruit setting rate, prevent organic matter from being transported downwards, and concentrate nutrients on the upper part of the stripped branches; Hinder root growth and inhibit water absorption;
2. The magnitude of these effects depends entirely on the time and width of girdling and the cooperation of other cultivation measures. Therefore, in order to give full play to the role of girdling, it is necessary to decide whether this method is suitable according to the tree species, and also to grasp the width and depth of girdling and the time of girdling. In order to avoid the negative impact of ring cutting, comprehensive treatment should be carried out after ring cutting;
3. After the walnut is circumcised, its reaction is the same as that of other fruit trees. Because girdling cuts off the organic nutrition connection between the upper and lower parts, the inorganic nutrients absorbed by the roots are supplied to the aboveground parts, and the organic nutrients made by the leaves are not transported to the roots, so that the aboveground parts are relatively rich, which is beneficial to flower bud differentiation;
4. The root system can't get the supply of organic nutrients temporarily, so the growth is inhibited, the absorption is reduced, and the inorganic nutrients supplied to the leaves are reduced, which inhibits the growth of branches and leaves. If only some branches are peeled off, the peeled branches are controlled and have little effect on the root system. So generally speaking, the ring cutting of walnuts is to cut big trees, not small trees and twigs.
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