Urea is the nitrogen fertilizer with the highest concentration in solid nitrogen fertilizer produced in China, and its aqueous solution is neutral. In addition to the basic fertilizer used in crops, the vast majority of crops are used for top dressing. So, how can we increase the effect of urea fertilizer? The following should mainly be done:
1. Determine the amount of fertilizer according to soil fertility
Practice has shown that increasing the amount of fertilizer applied to the middle and low-yielding fields can significantly increase production. For high-yielding fields, the general level of fertilization can be maintained. Generally, on the basis of applying sufficient fertilizer and chemical fertilizers as base fertilizers, taking the two major crops of corn and sorghum as examples, in the high fertility soil, topdressing 20 kg per mu, and in medium fertility soil, applying 23 kg per mu; In low-yield soil, 27 kg should be applied.
2. Composting at the peak of crop nutrition
The main function of topdressing is to use fertilizers to regulate the growth and appearance of crops, to meet the nutritional needs of crops in the middle and later stages of fertility, and to increase production. The key to increasing the utilization rate of chemical fertilizers is to grasp the critical period and maximum efficiency period of nutrient absorption of various crops, and try to top-dress fertilizers during the nutrient-rich period of crops in order to increase the utilization rate of fertilizers. Corn should be in the jointing period to the big bell-mouth period, sorghum should be in the jointing stage to the booting stage, rice from the green stage to the tillering stage, sunflower in the budding stage. During the three-leaf period of wheat, soybeans topdressed with urea at the early flowering stage.
3. Doing deep soiling
Practice has proved that when urea is applied on the ground surface for 4-5 days at room temperature, most of the nitrogen will be volatilized by ammoniating, and its utilization rate is only about 30%, especially on the surface of calcareous and alkaline soils, its ammonia Volatile losses are even more severe. Therefore, when urea is used to top-dress dry farm crops, it is better to grind the pits or deepen the ditch for less than 10 cm, so that the urea can be contained in the moist soil, which is conducive to the conversion of urea and is also conducive to the ammonia fertilizer. Adsorption reduces volatilization losses. When topdressing rice with urea, the depth of the water layer should not exceed 3-5 cm.
4. Keep a distance from the crop
Due to the high nitrogen content of urea and the high concentration of nutrients, it has great hygroscopicity. Therefore, when topdressing, it is necessary to prevent urea from being applied near the roots of crops, and it is even more important not to drop urea into the heart of the crop so as not to burn the seedlings and affect the growth. Therefore, it must be kept at a certain distance from the crop.
5. Advancing earlier than other nitrogen fertilizers
Because urea is a kind of low-molecular organic compound, there must be an amination process after it is applied to the soil. That is, under the action of the urease secreted by the decomposing bacteria, it can be transformed into a highly volatile ammonium carbonate before it can be used as a root system. absorb. Therefore, using urea to topdress crops should be applied about 7 days earlier than other nitrogen fertilizers.
6. Do not mix with alkaline fertilizers
Urea is a neutral fertilizer and should not be mixed with alkaline fertilizers at the time of top dressing to prevent the decrease of fertilizer efficiency. If non-mixed application with alkaline fertilizer is not possible, it is also necessary to stagger the fertilization date, usually every 3-5 days. However, when urea is mixed with potassium chloride, phosphate rock powder, and superphosphate, the effect of increasing production is significant.
7. Not suitable for immediate irrigation after topdressing
After urea is applied to the soil, it cannot be absorbed by the soil before it is converted and transformed. If you fill water immediately after chasing, it will cause a large loss of urea. Soil water shortage, non-irrigation can not be time, but also to do small ground irrigation, avoid flooding irrigation. When topdressing rice, it should be considered that urea is more mobile before conversion, and even after topdressing, it cannot be immediately filled with water. Generally, it is advisable to fill small water once every 3-5 days after recovery.
8. Do top dressing
Urea has less damage to crop leaves, and is easily soluble in water. It is highly diffusive and easy to be absorbed by leaves. It is not easy to cause plasmolysis after entering the leaves, so it is suitable for top dressing. However, urea with a biuret content of not more than 2% should be used to prevent damage to the leaves. The concentration of urea as the topdressing fertilizer varies depending on the type of crop. The concentration of topdressing fertilizers outside the crops is 1.5%–2%; the concentration of top dressings for dicotyledonous crops is 1%. The period concentration should also be smaller. Generally, the amount of topdressing fertilizer outside the urea root per mu is 0.5-1.5 kg. The spraying time is suitable after 4 pm, when the evapotranspiration is small, the leaf pores gradually open, and the diluted urea solution can be absorbed completely at one night, which greatly improves the utilization rate of urea.
Medical Vinyl Glove
1.Type:Powdered or Powdered free ,medical vinyl glove
2. Different colour :Nature ,Blue ,white ,yellow etc. for hospital examination after surgical.
3. Passed Certification: CE,FDA510K ,EN455,EN374,ISO9001,ISO13485 etc.
4.Medical grade,AQL:1.5,2.50,4.0 ;
5.Size: S,M,L,XL,XL etc. and weight as your requirement.
6.no latex and non sterile
7.beaded cuff;sigle use only
8.soft and comfortable.
9.OEM or ODM packing.
10.usage widely for hospital medical examination,health care,hotel ,restaurant ,home cleaning etc
Medical Grade Vinyl Glove,Disposable Medical Gloves,Medical Examination Gloves,Disposable Gloves
Zibo Hongye Shangqin Medical Science and Technology Co.,Ltd. , http://www.vinylgloves.cn