Causes and Prevention of Frozen Damage to Apple Trees

<

In winter, when the temperature suddenly drops, the apple trees are vulnerable to freezing damage. Understanding the causes of apple tree frost damage and the prevention and control measures have become the focus of winter for fruit farmers. To this end, the reporter recently interviewed Zhang Zhicheng, a member of the Expert Advisory Group of the newspaper and the fruit specialist of Northwest Agriculture and Forestry University.

Frost damage

Zhang Zhicheng said that the various parts of the apple tree have different characteristics, so the reasons for their frost damage are also different. The main reason for frost damage of branches is that due to the sudden drop in temperature, the bark rapidly cools and shrinks, causing the trunk to crack from the outside to the inside. The time of frost cracking mostly occurs at night. When the winter temperature falls to -25°C, the branches are prone to frost damage. When the minimum temperature drops to -30°C, the whole tree will freeze. Root and neck freeze injury is due to the root neck into the dormancy period at the latest, and the first to lift the dormant and start activities, sudden cooling, the surface temperature changes violently, so the most vulnerable to freezing. Flower buds are organs with weak cold resistance. The better the differentiation, the worse the frost resistance. In the winter season, the temperature is not stable, and the short-term warming causes the cold resistance of the flower buds to fall. Frequently, the hot and cold temperatures often cause the flower buds to freeze and damage. In early spring, the flower buds are released from dormancy, and the flower buds are most likely to be frozen when they fall. The critical low temperature of frost during flowering, flower bud period is below 3.6°C to minus 2.8°C; flowering period is below 1.6°C to minus 2.2°C.

Frost damage prevention measures

During the various growth stages of fruit trees, the tree vigor must maintain a relatively stable and robust posture. Water should be properly watered during drought, and timely drainage should be carried out in order to eliminate dense branches, leggy shoots, open angles, ventilation, and protect the leaves. Improve the ability of the tree to resist cold. It should also be in the spring and summer seasons trunk coated fruit friends amino acids, Pu De Jin 4 to 6 times, can play a certain role in antifreeze. Reasonable fertilization ensures healthy growth of fruit trees. In summer and autumn, more phosphorus and potassium fertilizers are applied. In the autumn, basic fertilizers such as Dimijia and Wotianjia are applied. In the late autumn and early winter, the main trunk and large branches are painted white, which can reflect direct sunlight to prevent sunburn, and can also kill pests, eggs and spores, reducing the occurrence of pests and diseases.

After freezing injury, the frozen damaged shoots shall be trimmed in time. For the main branch and the main frozen apple tree, the shoots sprouted from the branches and stem bases shall be cut short at the full shoots to promote their branching. Then each level of bone branches can be cultivated separately, and the length should be shortened within 2 to 3 years to control the results so as to facilitate the rapid increase of the number of shoots. For fruit trees with less freezing damage, the main, lateral branches and permanent auxiliary branches should all be cut short at full shoots to promote tree development. In addition, some flower buds must be cut out to make it less fruitful so as to restore the tree vigor. In the case of frozen apple trees lacking shoots, they should use space to make up for space, cut lightly in 1 to 2 years, retain the amount of shoot buds, and promote their sprouting more branches. Within 3 to 4 years, each branch should be cut, and after the result, it should be appropriately retracted according to the crown space, and cultivated into a permanent auxiliary branch or result branch group. This will restore the canopy after 4 to 5 years of cultivation.

After frost damage at flowering stage, the flowers will be preserved, artificial pollination will be enhanced, and the fruit set rate will be increased. When the fruit set is too few, it is necessary to prevent the hair tips from becoming too prosperous.

Spine Board

Xray Spine Board,Detached Spine Board,Carbon Fiber Spine Board,Ambulance Transfer Spine Board

jiangyin chenyi medical technology co.,ltd , https://www.chenyimed.com