How to prevent walnut tree drawing
Due to the effect of low temperatures in winter and spring, many walnut saplings in our province have sluggish and even die. There was a phenomenon of dead trees, and weather was the main cause. However, from the investigation, the higher the seedling height, the more severe the cold injury, which to a certain extent also shows that there are many problems in management.
First, the reason why walnut trees are prone to frost damage
1. Walnut young trees have poor cold resistance. The pith of walnut branches is larger than that of other tree species. The water content in the pith heart is extremely sensitive to the outside temperature, and it is too vulnerable to external hypothermia.
2. Ignoring the work of cleaning gardens in winter has caused excessive accumulation of pathogenic bacteria in orchards and the disease has been increasing year by year. In recent years, the growing season of fruit trees often appears continuous rainy days, and fruit growers have no habit of clearing gardens. The pathogens that remain on the diseased branches and leaves continue to multiply year after year, and various diseases are aggravated, which seriously affects the robust growth of trees.
3. In the growing season, the number of fights is small, and the concentration of the drug in the rainy season is not enough. The fruit growers replanted light tubes, and pests and diseases rarely fight drugs in the growing season. In the months of rain and rain, the number of sprayings was small and the concentration was not enough.
4. The soil moisture content is large. Walnuts are not suitable to be planted in plots with high moisture content, such as earthworms and clay soils. Otherwise, it will cause root rot and rot disease of walnuts. It is difficult for branches of diseased trees to overwinter.
5. Spring irrigation is too early, frozen water is too late, rainfall is excessive in autumn, or the terrain is excessive. The pith of walnut branches is extremely sensitive to the outside temperature. Whether it is early spring or late winter, the pith of sucking enough water is vulnerable to the external low temperature.
6. Walnut disease is heavy. The dead stem disease and rot disease of walnut are also the main causes of death from the dead branches of walnut trees in spring. Both of the diseases are fungal diseases. The pathogens overwinter on litter, and are spread by wind and rain insects in the following year. Once the disease occurs, the whole park is infected, causing a devastating disaster in the whole park.
Second, prevention and control measures
1. Remedial measures after freezing. If the freezing injury is too severe, the above-ground parts can no longer sprout buds and shoots at 5 cm on the ground, waiting for the emergence of new buds in the lower part and re-cultivation; the freezing damage is not heavy, but the immature tissue is drawn, and management can be strengthened. When the tree leaves, make up the fertilizer and water, apply amino acid leaf fertilizer to the trunk, spray more than enough (or green wind 95) and add potassium to the mixture 2 or 3 times on the ground to increase the number of leaves, improve the quality of leaves, and rejuvenate. Tree potential; topdressing nitrogen, phosphorus and potassium compound fertilizer, can also enhance tree vigor; lyrical drought should be poured once a thorough permeable; in addition to timely pest control work.
2. Walnut young trees should pay attention to buried winter. The newly planted saplings can overwhelm the buried soil. The saplings are toppled from south to north and are carried out in two stages. The roots are cushioned and reach the bended part of the trunk. The first time the buried soil is not too wet, dry soil is needed, and the surface of the mat is finely soiled (breaking the large mortar) and bury 5 to 10 centimeters. The second time buried 15 to 20 cm. The thickness of the two buried soils is 25-30 cm above the branches, and the soil is then photographed. 2 to 4 years old trees are not easy to bend, can be in the northwest side from the trunk 50 to 60 cm semi-circular soil rake, 50 cm high, can increase the ground temperature, early thawing, in order to facilitate the absorption of water. It can also be coated on the tree trunk, painted white, wrapped in paper or wrapped in plastic film, coated with polyvinyl alcohol.
3. Thoroughly clean the orchard during the winter season and burn or bury the fallen leaves. After walnut leaves are deciduous, it can be used 100 times liquid of fruit fukang or 100 times liquid spray of Schnering, once again, the effect is better after spraying at intervals of 20 days. Before spraying, walnuts were sprayed with 3 to 5 Baume degree lime sulfur. This will better prevent and control various diseases.
4. Apply timely irrigation and irrigation, enhance tree vigor, and increase the resistance of the tree to disease. In the early growth season, nitrogen fertilizer is mainly used, and phosphorus and potassium fertilizers are the main components in the middle and later stages. After the fruit is harvested, it can be expanded and deep-fed and the organic fertilizer can be applied. The amount of applied tree diameter can be used as the parameter, and how many square centimeters are applied. How much pound of organic fertilizer. Spring irrigation should not be premature and frozen water should not be too late. The daily temperature of the two measures must not be lower than 0°C.
5. Timely prevention of walnut blight and rot disease. Both diseases are fungal diseases and are highly contagious and can be treated with different diseases. During the dormant season, diseased branches are cut off, litter is removed and burned, and the overwintering insect source is eliminated; for the soil that is too viscous, excessively sandy, and excessively thin, it is necessary to improve and apply organic fertilizer to increase the tree vigor and improve disease resistance. Walnut rot disease control and apple approximate: spring shave smear 9281 (Gufu), appropriate dilution; or vertical strokes, spacing 1 cm, smearing apple sulfer, appropriate dilution, can also be used Ritchieshushu Kang 3 ~ 5 The liquid is applied twice; in the growing season, it is sprayed once or twice with 400-500 times of Guofukang; during the dormant season, Guofukang liquid is sprayed 100 times once after the deciduous and before germination.
6. Healthy leaves and trees. In the hot and humid seasons of July and August, there will be spotted leaves, brown spotted leaves, and anthracnose leaves at the bottom of the walnut tree or in the inner pot. Careful people regularly spray (spray 15 days apart) with three times of foliar fertilizer and mix in the fertilizer with some bacteria, or 1.5% polyoxin WP, 400-500 times solution or 3%, 600 times medium-mycinomycin. Can promote the healthy growth of trees.
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