Use fertilizer carefully
Applying chemical fertilizers to crops as seed fertilizers can play a role in timely replenishment of fertilizers and promote the early emergence of strong seedlings, but you should not dress seeds at will. For example, the soaked cotton seeds cannot be dressed with urea, because urea contains a small amount of biuret, which will cause the seed buds to become dehydrated and die during the seed germination process. Kiln ash potash fertilizer can not be used as seed fertilizer, because calcium oxide is very water-absorbing, and it becomes mature lime after absorbing water in the soil, releasing a lot of heat energy, which will affect the germination of seeds. Some chemical fertilizers should be used as seed fertilizers. Seeds that cannot be mixed overnight, such as superphosphate mixed with cotton seeds, will all damage the sprouts if they are planted the next day.
Avoid single species
In the application of chemical fertilizers, the law that should be followed is that nutrients are equally important and irreplaceable. The content of different nutrients in crops often differs by several times or even more, but they cannot replace each other. Such as single application of nitrogen fertilizer, carbohydrates are used to synthesize protein, chlorophyll and other nitrogen-containing compounds in a large amount, the formation of cellulose and pectin is very small, the stems and leaves grow wildly, the crops are late, the grains are not full, and they are prone to lodging or causing pests and diseases. . Chlorine-free crops, such as beans, sugar beets, watermelon, tobacco, etc. The application of chlorine-containing compounds will promote the hydrolysis of carbohydrates in crops, affect the formation of starch and sugar, and reduce yield and quality. There is also a partial application of certain trace elements, which will also have an antagonistic effect on other trace elements, depleting their respective effectiveness. Therefore, in agricultural production, formula fertilization should be vigorously promoted, so as to seek advantages and avoid disadvantages, and balance fertilizer effects.
Prevent excessive fertilization
Appropriate increase in chemical fertilizers can significantly increase crop yields. After the amount of fertilizer is exceeded, not only will the yield not increase, but it will reduce the yield. If the ammonium ion is excessive, it will affect the conversion of glucose to sucrose, reduce the sweetness, and cause nitrous acid poisoning of crops and inhibit the growth of new buds. Excess potassium ions will inhibit the absorption of calcium and magnesium. Therefore, when guiding the application of chemical fertilizers, fertilization should be based on the fertilizer requirements of the crop; fertilization should be based on the local soil and climate conditions at the time; fertilization methods should be paid attention to, quantitative fertilization, deep fertilization, and water adjustment; vigorously advocate or create conditions and sufficient Mixed fertilization of decomposed organic fertilizers enhances the complementary effect.
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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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