Causes and prevention measures of yellowing of leaves of red beauty citrus
Lin Fang
The ripening period of red beauty citrus is concentrated in November to December, with the large-scale planting of red beauty citrus in recent years, its yield and planting benefits have gradually increased, and the red beauty citrus has higher requirements for temperature and environment during the growth process, coupled with the increasing prominence of leaf yellowing and shedding, which has an important impact on the later growth of red beauty citrus, which shows that the prevention and control technology of strengthening the yellowing of red beauty citrus leaves is particularly critical.
1 Symptoms of yellowing of red beauty citrus leaves
1.1 Leaf vein yellowing
The yellowing of the leaf veins of the red beauty mostly occurs in young trees within 2 years of age, and after the leaves grow at the top of the new shoots, the leaf veins become thick and yellowed, and with the increasingly serious yellowing phenomenon, the entire leaf surface gradually loses green and yellows, and there is a distortion phenomenon. If the yellowing phenomenon is mild, it will only affect the top leaf; if the yellowing phenomenon is serious, it will lead to whole tree lesions, and eventually the leaf shedding is typical.
1.2 Yellowing of the flesh of the leaves
Once the yellowing of the leaf flesh of red beauty citrus will affect its normal photosynthesis, and finally lead to the shedding of new shoot leaves, if scientific and reasonable management methods are adopted, normal leaves can grow at the new shoots in the next season.
2 Causes of yellowing of red mandarin citrus leaves
There are many reasons affecting the yellowing phenomenon of red beauty citrus leaves, and surveys have shown that whether it is red beauty leaf veins or leaf flesh yellowing, it is caused by root problems, such as fewer root whiskers and root rot, which will affect the absorption of nutrients and trace elements by red beauty to a certain extent, thereby inhibiting the growth of leaves. The reasons for the damage to the root system of red beauty citrus mainly include the following aspects: First, when colonizing, the depth of colonization is not strictly controlled, which in turn leads to the infection of germs at the graft interface. Second, in the process of planting red beauty, due to the excessive application of chemical fertilizers, the planting base has soil compaction, acidification and other phenomena, resulting in the root system can not be ventilated. Third, the lack of scientific and reasonable fertilization methods, such as fertilizer applied too deeply, close to the root system of red beauty, uncorrupted organic fertilizer will cause harm to the root system of red beauty. Fourth, in the growth process of red beauty, if the grower uses herbicides such as licorice phosphorus for a long time, it will affect the growth of young trees. Fifth, if the red beauty is planted in a low water level and poor drainage area, it will affect the drainage effect of the plant, which will lead to the phenomenon of poor drainage. Sixth, the ambient temperature suitable for the growth of red beauties should be higher than 7 °C, if the local temperature is lower than 7 °C, it will cause frost damage. Seventh, in view of the phenomenon that the fruit was not cleared in time last year, it will cause the red beauty citrus to grow too weakly and the nutrient consumption of the tree body is too much. Eighth, red beauty citrus belongs to the miscellaneous citrus class, so it is more sensitive to viral diseases, and once affected by the virus, it will lead to weak tree body and yellowing of leaves.
3 Prevention and control measures
3.1 Seedlings and colonization
Red beauty citrus is different from other oranges, belongs to the highly hybrid varieties, however, its growth essence is inseparable from citrus, orange, orange, grapefruit, so in the growth process, the high incidence of citrus, orange, orange, grapefruit can also have a serious impact on red beauty citrus, such as yellow vein disease, atrophy disease, recession disease, ulcer disease and so on. In addition, the red beauty citrus planters should also pay attention to the quarantine work of yellow dragon disease, in the process of purchasing seedlings, should choose virus-free, healthy seedlings, and then improve the disease resistance of red beauty citrus, from the root to reduce the plant infection rate.
In the process of red beauty citrus colonization, it is necessary to adopt the colonization method of flat ridges and build piers on the ridges for cultivation. In the cultivation process of red beauty seedlings, its grafting interface should be at 2 cm in the upper part of the topsoil, in order to better protect the grafting interface, it should be coated with 80% manganese zinc 500 times liquid; in addition, it can also be coated with 70% methylthiocine 600 times liquid in the upper part, which can also play the same protective role, and the cultivation amount of red beauty seedlings per hectare of land is about 65 plants.
3.2 Fertilize
If the soil of the Red Beauty Planting Base appears acidified and compacted, it is necessary to apply more farm manure such as livestock manure, which in turn plays the purpose of improving the soil structure, so that the soil has the characteristics of deep soil layer and high fertility. In the actual fertilization process, the trenching and fertilization method can be adopted to cultivate the roots of red beauty citrus and promote the growth of the root system. If the soil acidity is too large, 6 kg of lime can be applied per hectare of land to supplement the trace elements inside the soil, and to ensure the uniformity of fertilizer application, to avoid fertilizer too close to the crop root system, the fertilization time can be selected before rain, which is conducive to the dissolution of fertilizer and improve fertilizer utilization.
3.3 Weeding
Artificial or mechanical weeding should be the mainstay to minimize the use of herbicides, and can also be laid on the side of the red beauty citrus growth of the anti-grass cloth, after 15 days, and then the other side of the anti-grass cloth is laid, which can increase the soil permeability of the field, improve soil activity, on the basis of avoiding weed breeding.
3.4 Drainage
Draining the orchard can play a crucial role in the growth of red beauty citrus, so a shallow ditch of about 30 cm can be opened in the field, and a deep ditch of 60 cm can be opened in another row, in addition, a deep ditch of 100 cm should be opened around the park. After the above work, the drainage efficiency of the orchard can be effectively improved, and the occurrence of water accumulation can be avoided to the greatest extent.
3.5 Freeze protection
It is particularly important to do a good job in the antifreeze work of red beauty citrus, which can be sprayed on its foliage with 600 times liquid and 400 times liquid of extraction no. 1, and cultivate red beauty in the greenhouse, so as to avoid the influence of cold air on the red beauty tree, frostbite, and prolong the harvest time.
3.6 Sparse flowers and fruits
First, should try to prevent the tree body has more hanging fruit, the yield per hectare of adult trees should be controlled at about 1 500 kg, if the red beauty growth is weaker, the amount of flowers is more, on the one hand, can effectively remove the spring fruit of the mother branch, as far as possible to reduce the red beauty fruit branch, promote other branches to absorb nutrients, increase the yield and quality of fruit trees; on the other hand, to do a good job in the management of the red beauty citrus blooming period and the flowering period, reasonable flower thinning operation.
Second, in the growth process of red beauty citrus, but also about 2 times of vegetable and fruit work, red beauty belongs to the big fruit, has a high commodity value, in the fruit to take a scientific and reasonable method. The first fruit thinning can be carried out in June to ensure the uniform distribution of the red beauty fruit; the second fruit thinning should be in August, especially to remove diseased fruits and residual fruits. All in all, the production personnel should make reasonable adjustments according to the specific growth of the red beauty tree to ensure adequate nutrient supply.
Third, for the red beauty citrus that has been harvested later, it is necessary to do a good job of observing the growth of the orchard trees, harvest the large fruits with poor commerciality in advance, leaving a perfect shape, healthy and high-quality fruits, in addition, it should be noted that the delay is actually picked before the end of January.
3.7 Foliar fertilizer
When the red beauty citrus is picked, it is necessary to apply an appropriate amount of foliar fertilizer, foliar fertilizer should be iron, zinc, boron, magnesium as the main components, to further improve the quality of the leaves of the red beauty citrus, to meet the plant's nutritional needs, promote the growth of the tree. In addition, 500 mL of Ritz can be used for rooting per hectare of land.
In summary, as an important variety of orange orange fruits, red beauty citrus can have an important impact on the development of agricultural economy, because the yellowing of red beauty citrus leaves is an important factor that endangers its growth, therefore, production personnel should carefully analyze the causes and take prevention and control measures from many aspects, thereby providing support for improving the quality of red beauty citrus.