Recently, a fruit farmer asked: When will the walnut trees be well-trimmed? According to the information, walnut tree pruning should grasp the three best periods, namely: after the discoloration of the walnut leaves to the former; winter months when the number of cold days; walnut trees sprout before the month. Some experts believe that due to pruning prone to dormancy during the dormant period and weaken the tree vigor, and even cause local branches dead, the appropriate pruning period of walnut trees to the fall fruit after harvest to the time before falling leaves is better, not suitable for pruning in winter. When will the walnut tree be cut? In fact, walnut trees can be trimmed throughout the year. The pruning time of walnut trees is different from other tree species. If the period is not appropriate, there will be a phenomenon of injuring the flow of water, causing loss of tree nutrients, resulting in weakening of the tree. In general, it is divided into dormant period and non-injury period. According to many years of experimentation by growers, the pruning during different pruning periods in spring, summer, autumn and winter has different problems, and the effect of pruning is also different. Spring pruning Spring pruning refers to the pruning that takes place after the walnut tree has sprouted to the front of the leaf. As temperatures continue to rise, after the tree germinates, nutrients stored in the roots are continuously transported upwards and nutrients begin to transform. At this time, the tree is in need of more nutrients. In this case, pruning will cause injury, and a large part of nutrients will be lost, which will weaken the tree vigor, reduce the fruit setting rate, affect the yield, reduce the quality, and reduce the income. If it is an unproductive or overgrown tree, pruning at this time can well control growth, weakening the tree vigor and giving early results. Therefore, early-spring varieties of walnut trees entering the early fruit period in spring should not be trimmed, and trees that grow too prosperous and ineffective should be cut. Early spring-pruning of early-fruit varieties can promote early results. Summer pruning Summer pruning must grasp the pruning period. After pruning, if the temperature reaches 30°C, the walnut fruits are exposed, which may cause burns and reduce the nutritional quality, thereby reducing the benefits. It has been observed that the best pruning starts from late May to the end of June. At this time, pruning was carried out by combining scion and cutting. The short cut was the main factor. The length of the shoots was 3 cm at most, and the buds or lateral buds were left and the spacing between the layers was left. The dense branches were removed and the drooping branches were retracted. After cutting, we must strengthen fertilizer and water management. Specific practice: spraying potassium dihydrogen phosphate 300 times from the end of June, once in 10 days, until the end of the fallen leaves. After 7 months, the application of nitrogen fertilizer was stopped, and phosphorus and potassium fertilizers were applied; water was not sprayed before August to fall; in the middle of September, paclobutrazol was used to control growth and enhance the pruning effect. The autumn trim was performed after the walnut was harvested until the leaves turned yellow (mid-September to early November). At this time, the leaves did not fall, there was no injurious phenomenon, and the dense branches and shading branches were easy to see, and they were removed to facilitate ventilation. However, the nutrients were not returned during this time, and the cut leaves and shoots contained a large amount of nutrients that were not returned. And autumn cut wounds to the winter, such as temperature instability, there will be a bad flow, and the branches less than 1.5 cm in diameter drawn slightly heavier (about 2 cm). Therefore, autumn shearing is suitable for the pruning of weak trees, old trees, and hillside walnut trees. At this time, there is no injury to fluent branches and promotes strong growth. The best period of winter pruning is theoretically suitable from the cold to the beginning of the Spring Festival. Injury of walnut trees generally begins after the fall of leaves and stops after the buds sprout in the coming spring. However, not all injuries occur during the rest period. When the temperature fluctuates up and down at 0°C, sometimes there is no injurious flow. When the temperature is stable at or above 0°C for a long time, the injurious flow shows little or no occurrence. In addition, the size of the injurious flow has a great relationship with the tree vigor, the environment, and the public opinion of the past year, and the injurious flow of the tree decreases with the increase in the grade of branches. It can be seen that as long as the actual situation of temperature and climate is every year, it is feasible to seize the favorable opportunity for winter cutting, but it is necessary to seize the middle and twigs during critical periods. Pruning at this time can ease the time conflict between spring, autumn and farmers. In short, walnut tree pruning should follow the following points: increase summer pruning efforts, do a good job after cutting management. Combine autumn and winter shears, cut big branches in autumn and cut branches in winter. Planters can choose the pruning period suitable for the region according to their actual situation.
There are mainly the following parts:
1. Sampling swab with disposable sterile plastic rod/rayon head
2. Sterile sampling tube containing 3ml of virus maintenance solution (gentamicin and amphotericin B are selected to better inhibit the fungus in the sample. Avoid the human sensitization reaction that may be caused by penicillin in the traditional sampling solution.)
In addition, there are additional parts such as a tongue depressor, a biosafety bag, etc.
Intended to use
1. It is used for monitoring and sampling of infectious pathogenic microorganisms by disease control departments and clinical departments.
It is suitable for sampling of influenza virus (common influenza, highly pathogenic avian influenza, H1N1 influenza virus, etc.), hand, foot and mouth virus and other types of viruses. It is also used for sampling of Mycoplasma, Chlamydia, Ureaplasma, etc.
2. It is used to transport nasopharyngeal swab samples or tissue samples from specific parts from the sampling site to the testing laboratory for PCR extraction and testing.
3. It is used to preserve nasopharyngeal swab samples or tissue samples from specific parts for necessary cell culture.
The virus sampling tubes are loaded with infectious substances, and some are even highly pathogenic substances. Therefore, the requirements for packaging containers are very strict, and three requirements must be met at the same time:
1. The safety of transportation.
Ensure that the sample does not leak during transportation. Sampling tubes that comply with WHO regulations and biosafety regulations.
2. The security of preservation.
Ensure that the sample does not leak during storage. Sampling tubes that comply with WHO regulations and biosafety regulations.
3. The validity of the sample.
Make sure that the sampling tube itself will not have a toxic effect on the sample.
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