The daily release of strong cooling, the cold wave has struck, the cold may cause certain harm to the kiwi tree, the frost may lead to tree lesions, affecting the growth and yield of the kiwi tree, kiwi fruit different development periods of the tolerance to extreme temperatures is different. Kiwi fruit has a higher tolerance to low temperatures during dormancy and lower tolerance to low temperatures during the growth phase.
Common varieties are resistant to low temperature performance
1. Delicious kiwifruit
Delicious kiwi varieties can tolerate short-term low temperatures above -15 °C and long-term sustained low temperatures above -12 °C after the winter branches enter full dormancy, while only short-term low temperatures of -1.5 °C and -0.5 °C can be tolerated after budding and before leaf fall.
2. Chinese kiwifruit
Chinese kiwi varieties are less tolerant of low temperatures than delicious kiwifruit. Its tolerance to extreme minimum temperatures is about 1 to 2 °C higher than that of delicious kiwi varieties, that is, short-term low temperature hazards above 0.5 °C and -10 °C can be tolerated in the growing season and dormancy season, as well as constant low temperature hazards above 1.5 °C and -8 °C, respectively.
The dangers of frostbite
1. Buds
The harm of the sudden sharp cooling and the low temperature of the ultra-tolerance limit to the kiwi fruit is manifested in the early spring as the buds are frozen, the organs in the buds cannot develop normally, or the developed organs become brown and die, resulting in the buds cannot germinate normally.
2. Branches and fruits
Or germinating young shoots, young leaves discolored, death. The frost damage in late autumn is manifested as the young shoots that are too late to fall leaves normally, the leaves dry up, brown and die, and hang on the branches and vines without falling off;
Fruit that has not been picked, the causal stem does not produce a detached layer, it is difficult to pick, it does not pass the post-ripening stage after picking, the fruit cells are not separated, and it is always hard and inedible;
The frost damage in the dormant season is manifested as branch cracking, branch dehydration, commonly known as "plucking or drawing", the buds are frozen and underdeveloped, or the surface is alive and dead, and cannot germinate.
Sometimes although the degree of temperature reduction does not reach the above indicators, it is accompanied by low humidity and high winds, commonly known as "dry and cold wind", which will lead to severe branch loss of water and dryness, striping, or longitudinal cracking of large branches, or even the death of the whole plant.
Kiwi frost damage protection
1. Shake off the snow on the kiwi tree in time to shorten the freezing time of the tree.
2. Pile up grass smoke at a certain point in the kiwi orchard to promote the rapid melting of ice and snow on the tree body.
3. Conditional can be covered with film on the canopy or trellis to protect the canopy, and weeds or small branches, bamboo branches, etc. can also be put on the canopy or trellis to reduce the harm of ice and snow to the branches.
4: Brush the white trunk and main branches with 10% fresh lime.
5. Spray the tree body with 3-5 baume degrees of stone sulfur compound or 600 times liquid of 600 times liquid of agricultural resistance 120 or 500 times liquid after the ice and snow melt.
6. After the ice and snow melt, the branches crushed by the snow are cut off in time, and the scissors are smeared with 450-500 times of agricultural streptomycin.
7. Correct the trellis in time after ice and snow and sort out the branches.
8. Fertilize once before germination, and apply an appropriate amount of phosphorus and potassium fertilizer with fast-available nitrogen fertilizer as the main fertilizer, and irrigate with water.
Generally, 0.5-1.5 kg of urea and 0.2-0.5 kg of available phosphorus and potassium fertilizers are generally put into production;
0.2-0.5 kg of urea was applied to the unprovoked trees, and the appropriate amount was combined with the application of fast-available phosphorus and potassium fertilizer;
The first planted trees look at the dry and wet soil, only water and do not fertilize when dry, and drain and dehumidify in time when the humidity is high.
【Source: Department of Agriculture and Rural Affairs of Shaanxi Province_Production Technology】
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