How to deal with the freezing injury of apple trees?

In the process of winter cultivation, apples are easily affected by the sudden drop of temperature, which leads to freezing injury. Therefore, it is necessary to take preventive measures in the early stage of freezing injury. School Easy Search provides some precautions for your reference. Pouring frozen water in time: Pouring frozen water is an important cold-proof measure. Generally, it should be completed before the soil freezes. Not only should the frozen water be thoroughly irrigated, but also the water in the low-lying areas of the orchard should be avoided. After the soil is frozen, the frozen water will have a serious adverse effect on the root system. Trunk whitening: before winter, the trunk and main branches of apple trees should be whitened, and the drying height should be above1m. Tree trunk whitening can not only kill bacteria and insects, but also prevent freezing injury in winter. In winter and during the day, the trunk temperature is high, the trunk color is dark, and it is easy to absorb heat. Therefore, the temperature of the trunk rises quickly, and the temperature of the trunk is low at night. If it is not painted white, the temperature difference on the surface of the trunk changes greatly, and the trunk is easy to freeze and crack. Those plants that grow vigorously and stop growing in late autumn are more susceptible to freezing and bark cracking. After the trunk is painted white, it can effectively reduce the temperature difference between day and night and keep the temperature relatively balanced. Therefore, after entering the middle and late period of 1 1, the trunks of the whole park should be painted white in time. The proportion of white coating agent is quicklime 10 kg, sulfur powder 1 kg, salt 0.2 kg and water 30 kg, which are mixed into paste and evenly coated on the trunk. Straw mulching between rows and tree tray mulching: crop straw, leaves, etc. Covered between rows after autumn, with a thickness of 5- 10 cm. It can not only preserve soil moisture, but also effectively increase ground temperature and prevent freezing injury. For the tuyere position or weak trees, cover them with film within the diameter range of 1m to prevent water evaporation and ground temperature loss. Plastic film mulching should be carried out after irrigation and cultivation in winter. Topsoil: Topsoil around the root neck before winter. Raise the soil along the periphery of the tree tray to the trunk, and the height is generally not more than the first branch. Dig out the soil after the temperature rises in early spring next year. You can also cover it with grass, but you should press the grass properly and pay attention to fire prevention. Delayed pruning to protect the wound: the pruning time in winter is appropriately delayed, and the secondary winter pruning technology is adopted, that is, the apple tree is pruned for the first time before the arrival of cold winter, and the pruning amount is 70%-80% of the total pruning amount; After the severe cold, the second pruning should be carried out before the end of the dormancy period, which is an auxiliary pruning in winter. In winter, dead branches and excessive branches should be cut off, and branch protectant should be applied in time to protect the wound. Wrap the trunk: pay close attention to the temperature change. If the temperature drops below MINUS 20 degrees, it may cause freezing damage to trees. Trunks and branches should be wrapped with waste cotton wool, cloth strips, crop straws, weeds and other items in time, and tied with waste agricultural films and woven bags. When wrapping the trunk with straw, pay attention to the straw head pressing the straw tail and tying it tightly, and don't freeze the water in the grass. Shake off the snow in the crown: Shake off the snow on the tree in time after heavy snow to prevent the sudden change of temperature day and night and the melting of snow and ice from causing freezing damage to the trunk and aggravating the occurrence of rot. When freezing injury occurs, don't hit the frost on the crown with a stick, so as not to knock off the branches and leaves and aggravate the freezing injury. Make a good weather forecast: timely forecast the occurrence and duration of disastrous weather throughout winter, especially the absolute low temperature and cold wind. Prepare for freezing before bad weather and take various measures to protect trees for winter. Taking measures such as straw wrapping and smoking to raise local temperature can prevent or reduce freezing injury. For apple trees damaged by freezing, the following remedial measures should be taken: trees that are not seriously damaged by freezing can gradually recover if their cambium and buds are light.