Which parts of fruit trees are vulnerable to freezing damage in winter? How to prevent it?

For fruit trees, it is easy to suffer frost damage in relatively cold winter. if targeted preventive measures are not taken, it will undoubtedly be a big blow to fruit growers, so which parts of fruit trees are vulnerable to frost damage in winter? How to prevent it?

First, which parts of fruit trees are vulnerable to freezing damage in winter?

1. Root freezing injury.

Because the roots of fruit trees do not have natural dormancy, the roots on the surface are vulnerable to freezing damage. The root system is frozen in winter and is often difficult to find. After the branches sprouted in the spring next year, after a period of time, the branches and buds suddenly wilted, mostly due to the freezing of the roots. Preventive measures: prevent early defoliation, control growth and promote strong in autumn, promote nutrition accumulation, fill enough frozen water.

2. Root and neck frost injury

Because the root neck stops growing the latest, and starts to move earlier, the cold resistance is poor, and it is close to the surface at the same time, and the temperature changes greatly, so the root neck is vulnerable to low temperature and large temperature change, which makes the cortex frozen, turn brown and then dry or rot. Preventive measures: root neck soil.

3. Main stem freezing injury

First, the trunk sunburn to the sun, because of the large temperature difference between day and night in early winter and early spring, the skin tissue is active with the increase of sun temperature, and the temperature drops suddenly at night. Second, the trunk is longitudinally cracked, due to the sudden drop in temperature in early winter, the cortical tissue shrinks rapidly, the xylem produces stress and stretches the bark, and the cell gap freezes, which can also cause cracks. Preventive measures: the trunk is painted white and covered with grass.

4. Freezing injury of branches

It mainly occurs on the inward side of the branch. The symptoms are cortical discoloration, necrotic depression, or vertical fissure of the trunk. Due to narrow annual rings, undeveloped ducts, poor support, less nutrient accumulation, poor cold resistance and other reasons, the branches will be glued in the coming spring. At the same time, because the bifurcation is easy to snow, after melting snow to infiltrate the bark to make the tissue soft, the sudden drop in temperature will suffer. Can be used trunk wrapped grass, branch hanging grass and other methods to prevent cold.

Second, how to prevent frost injury of fruit trees in winter?

1. Strengthen the management of fertilizer and water

Strengthening the management of fertilizer and water is helpful to the storage of nutrients in trees. Strengthening fertilizer and water in spring can also promote the growth of new shoots and the increase of leaves, improve the efficiency of photosynthesis and ensure the health of trees. Controlling irrigation in autumn, timely drainage, proper application of phosphorus and potassium fertilizer, weeding and deep ploughing can promote the end of branch growth in time, enrich the tissue and prolong the accumulation of nutrients.

2. Timely winter irrigation, watering frozen water

Reasonable winter irrigation can not only ensure that the aboveground parts of plants absorb enough water, but also protect the underground roots against dry and windy winter, and prolong the flowering period of flowering plants in the coming year. Generally, when the soil temperature is higher than 5 ℃, the plant roots absorb water, but when the soil temperature is lower than 5 ℃, the plant roots can not absorb water. Therefore, it is necessary to pour water once before the ground temperature is lower than 5 ℃. When the soil temperature is below 0 ℃, the soil will freeze because of water, and water should also be watered once to keep the roots from being drained by the wind. When the temperature is lower, the frozen water at the root can release latent heat and increase the temperature. Therefore, winter irrigation should be carried out twice, in late October and early November.

3. Strengthen the measures of anti-freezing and heat preservation:

① neck soil

After winter water irrigation, combined with sealing Weir, a soil pile with a diameter of 50-80cm and a height of 30-50cm was planted on the root neck of the tree, which could not only prevent frostbite of the root neck and roots under low temperature, but also reduce the evaporation of soil water.

② cover soil

When the soil has not thawed in early spring, it is difficult for tree roots to absorb water. At this time, the air is dry, the temperature rises quickly, and the evaporation is large, which is easy to cause physiological drought and withered shoots of plants. In view of this phenomenon, the seedlings can be buried in the soil all winter before and after the Beginning of Winter, so that the seedlings and nursery bed soil can maintain a certain temperature, which is not affected by the sharp change of air temperature and other external adverse factors. At the same time, it can reduce the transpiration of seedling water and the evaporation of soil water, maintain a certain amount of soil moisture, help to maintain the water balance of seedlings, and effectively prevent the death caused by freezing injury and physiological drought of seedlings.

③ wind barrier

In order to reduce the damage of trees caused by cold and dry winds, wind barriers can be erected in the upwind direction of trees.

④ trunk binding

It is to bind the trunk of fruit trees with straw, straw and withered grass to protect against cold by increasing the thickness of the trunk, which is the same as the effect of clothing in cold weather.

4. Use fruit tree whitening agent

Trunk whitening agent is a product of insect prevention and heat preservation for all kinds of trees, such as gardens, ecological trees, street trees, fruit trees, etc., which can effectively shield ultraviolet rays, protect the trunk cortex and reduce the damage caused by sunburn. and has the characteristics of cold prevention, insect prevention, disease prevention, insecticidal eggs, pika harm and so on. The coating can not only prevent the aging of trees, but also insulate the trees and make the trees grow better; after special material treatment, it has a long-term adhesion to prevent Rain Water from scouring and causing shedding. Wallingdun whitening agent can be used for whitening products.