Measures for burning fruit trees

In a year's growth cycle of fruit trees, when the weather is hot, the ambient temperature exceeds the appropriate temperature of fruit trees' physiological metabolism, which often leads to abnormal physiological metabolism, irregular growth, serious flowering and fruit drop, serious physiological metabolism disorder of branches or fruit trees, and plant withering. Generally speaking, high temperature heat damage is mainly manifested as local damage. The main manifestations are:

1. Thermal damage

When the fruit trees are seriously damaged by heat, the bark may dry, the leaves may appear necrotic spots, and the leaves may turn yellow and brown, which may delay the fruit ripening and affect the fruit quality.

Measures to deal with thermal damage:

(1) Strengthen soil management, improve soil, deepen living soil layer and increase soil organic matter content, which can be improved by using Trim microbial inoculum. Rational fertilization can alleviate the contradiction between vegetative growth and reproductive growth.

(2) In case of heat damage and dead leaves, irrigate in time to keep the soil moist.

(3) Conditional orchards can be covered with straw before high temperature, which can stabilize soil moisture, promote root growth, reduce soil moisture transpiration, reduce flower and fruit drop, or plant grass in the whole garden is beneficial to reduce heat damage.

Burn in the sun

Sunburn refers to the burning of organs and tissues of fruit trees during the growth cycle of one year due to strong solar radiation, also known as sunburn. After being sunburned, the peach tree has cracked epidermis, necrotic cortex and large transverse cracks. As a result, branches are easy to crack for a long time. Apples, pears, grapes, pomegranates and other fruits will also get sunburned from time to time. At first, brown or black spots appeared on the leaves, and the epidermis of the branches cracked and fell off, and then gradually expanded. Sunburn is also the cause of fruit cracking.

Sunburn countermeasures:

(1) painted white. The white coating on tree trunks and branches can reflect sunlight and alleviate the temperature change of bark. It is widely used in the north and has obvious effect on reducing the occurrence of sunburn.

(2) irrigate the soil. In hot summer, fruit trees need to evaporate a lot of water to reduce the surface temperature of organs. If the soil is short of water, it will aggravate the occurrence of sunburn. Therefore, in the case of high temperature and drought, the orchard should be watered in time. Relevant experiments show that under the same conditions, the daily sunburn rate of irrigated orchards is only 5%, and that of non-irrigated orchards is 14%. In addition, when high temperature weather comes, cold irrigation such as sprinkler irrigation or fog irrigation can make the surface temperature of fruit trees drop rapidly, thus effectively preventing the sun from burning fruit trees.

(3) spraying protective agent. Before sunburn, spraying lime on the canopy can reflect sunlight, reduce the temperature of the canopy and effectively reduce the occurrence of sunburn of fruit trees. The results showed that spraying salicylic acid could significantly improve the activities of superoxide dismutase and peroxidase in skin tissue after high temperature stress, and improve the resistance of fruits to sunburn.

(4) Adopt correct bagging technology. Fruit bagging can avoid direct sunlight and change the microenvironment of fruit, and bagging can reduce the occurrence of sunburn to some extent. However, the bagging technology must be standardized, the fruit should be hung as much as possible, the two air holes at the bottom corner of the paper bag must be completely opened, and the bag should be removed gradually according to the type of the fruit bag and the weather conditions to avoid or reduce the continuation of sunburn and the effective coloring of the fruit.

(5) Reasonable shaping and pruning. Cultivating a reasonable tree structure in orchards prone to sunburn and taking appropriate pruning measures can reduce the occurrence of fruit cracking due to sunburn. When pruning, pay attention to cultivate the tree shape, leave more branches and leaves in the southwest direction of the crown, avoid direct sunlight of the fruit, reduce the height of the branches, and leave more auxiliary branches to prevent the branches from being sunburned.

(6) fruit protection. In order to prevent the fruits from being sunburned by the sun, more semi-shaded fruits should be left around the tree crown and pruned properly to achieve the purpose of "hiding the fruits in the leaves"