1. Antifreeze management measures
1. Apply fertilizer to restore tree vigor
After the fruit is picked, use quick-acting fertilizer to add water to the roots, or combine with foliar sprays to supplement nutrients, promote the rapid restoration of tree vigor, increase nutrient accumulation, make the tree grow stronger and enhance cold resistance.
The specific requirements are: 0.2-0.3 kg of potassium dihydrogen phosphate plus 0.5 kg of urea or 100 kg of high-grade compound fertilizer per mu to spray outside the roots. Then reapply the organic fertilizer, generally applying the decomposed organic fertilizer according to the proportion of the fruit.
The fertilization methods are: one is to adopt circular fertilization method (that is, to dig a ring-shaped ditch at the drip line of the tree); the other is to adopt a radial fertilization method (that is to dig 4 to 5 ditches at the drip line); the third is to adopt a strip ditch. Fertilization method (dig 2-4 straight trenches at the drip line), the depth is about 30 cm.
2. Peking soil
Combine pruning and clearing the garden, plowing and fertilizing, selecting pond mud, river mud, field soil, etc., and cultivating soil 20-30 cm thick on the root neck tree disc.
3. Protect the tree
â‘ Covering and protecting the crown: the young tree is wrapped with straw, and the mature tree is covered with a film to prevent direct frostbite of the branches and leaves.
â‘¡Protect the main branches. Wrap up with straw or woven bag to reduce temperature difference and prevent frostbite of branches.
4. Timely artificial antifreeze
â‘ Chemical antifreeze: Before low temperature, spray antifreeze on the crown to promote the accumulation of cell sugar, inhibit leaf water transpiration, reduce the heat loss of the tree, and reduce the degree of frost damage.
â‘¡ Physical antifreeze: First, water or spray water for heat preservation. Pay attention to the weather forecast. Fully irrigate the orchard 10-20 days before the occurrence of low temperature and spray water on the canopy during the frost period to reduce freezing damage with water insulation. The second is to increase temperature by smoking. Before falling frost, use firewood, wood chips, chaff, straw and other materials to ignite and burn smoke. Set up 4-6 smoke stacks per acre of orchard to form a smoke screen over the orchard to suppress radiation and frost. At the same time, it can make the orchard Directly increase temperature and reduce freezing damage.
2. Management measures after freezing
(1) Management measures after freezing damage of citrus, navel orange, bayberry and other evergreen fruit trees
1. Canopy care after freezing.
After the fruit trees were frozen, the above-ground parts suffered varying degrees of damage or withered. While repairing the damaged branches of oranges, all the leaves should be removed. Bayberry and other evergreen fruit trees should be pruned in time to restore the crown as soon as possible to reduce losses.
2. Loosen the soil to increase temperature, and irrigation to restore the sun.
Loosen the soil under the canopy immediately after thawing to increase the soil temperature, especially after drying and freezing, the roots and body of the tree need more water, so water should be timely irrigated.
3. Saw the damaged branches and apply wound protection agent.
Pruning or sawing dry after freezing must be done at the right time, that is, cut off dead branches or saw to dry out when new shoots are sprouting and the line of life and death is clear.
The principle is to cut off the dead parts and keep all the living branches. In this way, it is not only conducive to the accumulation of nutrients in the tree, but also promotes early budding of new shoots. When pruning or sawing dry, larger wounds should be painted with protective agent to reduce water transpiration and prevent pests and diseases.
In principle, the new shoots that are taken out after freezing should be kept more, but 2-3 new shoots from one bud eye should be thinned out to ensure the normal growth of the new shoots and avoid the canopy closure.
New shoots that have grown too vigorously should be topped in time. After the fruit trees suffer from snow damage, they should be coated with protective agents (lime-sulfur mixture, paint, etc.) to prevent rot. The branches that have been scattered and not broken should not be sawed off easily. They should be supported with ropes or pillars to restore the original shape, and then apply wax oil, fresh cow dung, yellow mud, etc. to the injured area to promote healing and restore growth.
The unharmed branches and leaves should be pruned as lightly as possible. The branches that have been torn and tied should be pruned according to the severity of the injury to reduce the consumption of nutrients and water.
The new shoots drawn from below the broken branches should be properly retained for renewal and rejuvenation. In addition, the broken young trees or mature trees can be replaced by high grafting. Old trees that cannot be renewed should be replanted.
4. Fertilize reasonably to restore tree vigor.
After freezing, the function of the tree body will be weakened. Spring fertilization should be water-carried fertilizer and quick-acting nitrogen fertilizer. Apply thinner and thinner frequently, and avoid excessive fertilization. Nitrogen was the main fertilizer for the first time, and phosphorus and potassium fertilizers were added appropriately for the second and third time. In addition, foliar topdressing and supplementation of trace elements should be carried out in a timely manner.
5. Pay attention to flower thinning.
Frost-damaged trees have more deformed flowers and outdated flowers, especially light-frozen trees have a large amount of flowers and a low fruit setting rate. In order to reduce the nutrient consumption of the tree body during flowering, the deformed flowers and outdated flowers are generally removed from the lightly frozen trees to increase the seat Fruit rate. Refreeze the tree without leaving flowers, and urge it to restore its vigor as soon as possible.
6. Prevent pests and diseases.
After freezing, some branches are dead or damaged, and the branches and trunks are bare. In the high temperature season in summer, it is easy to cause sunburn and cracking of the skin. The resin disease is most likely to occur. Generally, in early summer and late autumn, first scrape off the diseased skin, and then use 1:4 alkali Water, wash 2-3 times, can achieve better results, also can use lime sulfur mixture to brush the branches to prevent sunburn.
In addition, special attention should be paid to the prevention and control of aphids, wind butterflies, leaf rollers, mites, leaf miners and other diseases and insect pests to promote the normal growth of new shoots and young leaves.
(2) Management measures after freezing injury of deciduous fruit trees such as pears, peaches, apples, and kiwis
1. Saw the injured branches and apply wound protection agent: After the overwintering branches of young trees are frost-damaged, they can be observed about half a month after germination (injured trees generally germinate half a month to 1 month later), and cut off the dry branches. Partially, grafting fine varieties in spring (peach trees are grafted in summer), the grafting methods are usually split and cut. Apply 3 to 5 Baume Duo Lime Sulfur mixture on the saw and cut.
2. Reasonably thin flowers and fruits, control the amount of results, restore the growth of the tree as soon as possible, and promote the healing of damaged parts.
3. Strengthen fertilizer and water management: After fruit trees are frozen during the flowering period, top dressing and irrigation should be made as soon as possible to promote their recovery.
4. Prevent and control pests and diseases and replant new trees in time.
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