“Little old tree†refers to the Shatian pomelo seedlings planted within 3-5 years of premature aging, becoming small and old aging trees, showing no production for many years, lack of plants, appearance is not good, the appearance of a fishing rod shaped like . This type of tree can be transformed into production and yield. 1. Deeply turning over and improving the soil and cultivating a strong root group “Beginning winter†to “Winter solsticeâ€, dig the trenches around the tree tray year by year, requiring a ditch depth of 0.8-1 meter, a length of 1-1.5 meters, and a width of 0.6-0.8 meters. Deep application of green manure, pig cattle manure, chicken manure, pond mud, etc., to increase fertility, in order to facilitate the growth of the root group. Second, increase fertilization water, cultivate a strong spring and autumn shoots with the defecation of fecal water mainly with the right amount of chemical fertilizers, focusing on the spring and autumn tips of fertilization. When spring shoots and autumn shoots turn green, 0.5% urea, 0.2% trace fertilizer, and 0.3% potassium dihydrogen phosphate are sprayed outside the roots to promote shoots robust. In case of drought, water should be poured in a timely manner. Water should be drained in a timely manner in the rainy season and water should be properly controlled in winter. Third, timely prevention and control of pests and diseases in the clearing of the winter garden, spraying pesticides to eliminate overwintering pests, especially in the new shoots when there are long grains, timely spraying of 2000 times of kungfusin solution plus copper chloride 800 times liquid prevention and treatment Leafminers, Papilio and Peptic ulcers were sprayed once every 5 days. After shoots turning green, spray 20% broom-barrel net wettable powder 2500 times liquid to control red spider, and use 1.8% Chizilla pestle gem EC 5000 times liquid to prevent rust spiders. In late April to early May and late in July, spray 40% speed cull 800 times to control scale insects to protect the leaves. Fourth, reasonable pruning, cultivation of high yield canopy focus on winter pruning, cut off pests and branches, dead branches, cross branches. Too weak trees, based on the management of fertilizers and waters, can be cut short and heavy (retaining more vigorous shoots) to allow them to re-emerge the robust shoots so that the ratio of height to height of the trees is 1:1.2-1.5. Within range. Fifth, timely replant, do a good job of protection on the park too weak plants and lack of plants should be replanted as soon as possible, pay attention to do a good job of sun protection work, the larger branches with wax coated fracture and straw dressing. At the same time, 6-7 cm thick grass cover the ground in the canopy to protect the root group. Sixth, promote the strong fruit In the third year after the rejuvenation, take the technical measures to promote and protect the flowers. (1) Focus on the application of 5 times fertilization on fertilization, cultivar, fruit stabilization, tipping, and shoot growth in fertilization. Apply 0.5 kg of urea, 0.75 kg of compound fertilizer, and 0.75 kg of superphosphate throughout the year. 0.75 kg of potassium chloride and 250 kg of organic fertilizer with good quality. (2) Properly eliminate the excessively prosperous spring shoots, rationally remove buds, remove deformed fruit, disease and fruit. (3) Artificially assisted pollination was conducted, and Huaguoling was sprayed at the appropriate time to increase the fruit setting rate. (4) timely control of ulcer disease, scab disease, brown rot Phytophthora, leaf miner, Papilio, scale insects, red rust spiders, citrus pests and other pests. China Agricultural Network Editor
Centrifuge Tube
Centrifugal tubes are generally disposable experimental devices and are not recommended for repeated use. In order to save money, PP centrifugal tube can be reused according to the situation, but it needs to be thoroughly disinfected by high temperature and high pressure to ensure the scientific results of the experiment. PE material centrifugal tube, can not be high temperature and high pressure disinfection.
We all know that in plastic centrifugal tubes, commonly used materials are polyethylene (PE), polycarbonate (PC), polypropylene (PP) and so on. The performance of polypropylene PP tube will be relatively good. Therefore, we should consider the plastic centrifugal tube of polypropylene as far as possible when selecting plastic centrifugal tube.
Use method of centrifugal tube:
1. Because the graduated centrifugal tube is a metering device, it must be cleaned and dried before use.
2. When reading, be sure to observe the bending liquid level correctly, otherwise it will introduce a certain error.
3. When used, the number of centrifugal tubes should be determined according to the model of the centrifuge. For example, if a centrifuge with two tubes is used for a single test, the same volume of liquid must be loaded into the other centrifugal tube to maintain balance.
4. The centrifuge tube and the centrifuge casing should be compatible. Pipe should not be too long, otherwise it is easy to break when rotating. But it is not easy to be too short, too short pipe is unstable when rotating in the air, and easy to cause breakage. Too thick sleeve not into, too thin rotation instability, round mouth should be greater than the inner diameter of the casing.
5. After the centrifugal tube is placed into the casing of the centrifuge for stratified separation, it should be stopped naturally when it stops rotating, and it should never be forced to stop by external force.
Precautions for centrifugal tube:
When we use centrifugal tube, do not use a tube many times, pay attention to the sample volatilization and some radioactive or corrosive sample leakage; In the storage process, it is necessary to seal well; It is necessary to prevent the deformation of centrifugal tube in the process of use.
Lab Consumables Plastic Centrifuge Tube,50Ml Centrifuge Tube,15Ml Centrifuge Tube,2Ml Centrifuge Tube
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