Urea use "eight is not suitable"
2018-12-27 13:03:01
First, it should not be mixed with alkaline fertilizer or applied at the same time. After urea is applied, it must be converted into ammonia nitrogen to produce fertilizer effect. Under alkaline conditions, most of the nitrogen will become ammonia gas, so urea can not be alkaline with lime, grass ash, calcium magnesium phosphate. Fertilizer application or simultaneous application. Generally speaking, in summer and autumn, urea and alkaline fertilizer should be staggered for 3 to 4 days, and winter and spring should be staggered for 7 to 8 days.
Second, it is not suitable for mixing seed fertilizer. In the production process, urea often produces a small amount of biuret. When the biuret content exceeds 2%, it will poison the seeds and seedlings. Such urea enters the seeds and seedlings, which will denature the protein and affect the seed germination. Seedlings grow, so it is not suitable for seed fertilizer. If it must be applied as a seed fertilizer, avoid contact with seeds and fertilizers, and control the dosage.
Third, it is not appropriate to apply water immediately after application. Urea is an amide nitrogen fertilizer, which can be converted into ammonia nitrogen to be absorbed and utilized by crop roots. The transformation process varies depending on soil, water and temperature, and the time is long and short. Generally, it takes 2 to 10 days to complete. Immediately after irrigation or dry land is applied before heavy rain, urea will dissolve in the water and be lost. Generally, summer and autumn seasons should be watered 2 to 3 days after application, and water should be watered after 7 to 8 days after application.
Fourth, it is not appropriate to spread the table. Urea is applied to the surface and can be used after 4 to 5 days of transformation at room temperature. Most of the nitrogen is easily volatilized during the ammoniation process. The actual utilization rate is only about 30%, if it is in alkaline soil and organic matter content. When the soil is applied in high soil, the loss of nitrogen will be faster and more. Moreover, the shallow application of urea is easy to be consumed by weeds. Deep application of urea, melt fertilizer in the soil, so that the fertilizer is in the moist soil layer, is conducive to the performance of fertilizer. For the topdressing should be applied to the seedlings or the ditch on the side of the seedling, the depth should be about 10~15cm. In this way, urea is concentrated in the dense layer of the roots, which is convenient for crops to be absorbed and utilized. Tests have shown that deep application can increase the utilization rate of urea by 10% to 30%.
Fifth, it should not be used too much. Urea has a high nitrogen content, and the application rate should not be too large, so as to avoid unnecessary waste and "fat damage". Generally, 5 to 15 kg per mu is applied, and 15 to 20 kg per acre is applied to the paddy field. Excessive application, can not be absorbed by the soil before conversion to ammonium bicarbonate, easily leached by rain, and easily damage crops. At the same time, too much urea is applied, most of which is lost, and entering the groundwater will cause nitrogen pollution in the water body, causing the deposition of nitrite, which seriously affects the safety of humans and animals.
Sixth, it is not suitable for high-concentration foliar application. Among all nitrogen fertilizers, urea is the most ideal foliar fertilizer. Spraying urea, the amount and speed of protein synthesis in crops exceeds that of other nitrogen fertilizers. However, when the foliar spray is applied, the concentration of the urea solution should not be too large, otherwise the leaves will be burned and the plants will be poisoned. Generally, the concentration of spraying on corn, rice, etc. is preferably 2%; vegetables and melons are preferably 0.5% to 1.5%.
Seven, it is not appropriate to apply too late. The application of urea is too late, which is not conducive to the exertion of fertilizer efficiency, and it is easy to cause crops to be late and mature, so it should be applied 4 to 7 days earlier than other nitrogen fertilizers.
Eight, should not be applied to celery. During the whole growth period of celery, a large amount of nitrogen fertilizer should be applied, but urea cannot be applied. Because the application of urea will increase the celery fiber to thicken, the plant aging, slow growth, and bitter taste when eating, the quality is inferior.
Second, it is not suitable for mixing seed fertilizer. In the production process, urea often produces a small amount of biuret. When the biuret content exceeds 2%, it will poison the seeds and seedlings. Such urea enters the seeds and seedlings, which will denature the protein and affect the seed germination. Seedlings grow, so it is not suitable for seed fertilizer. If it must be applied as a seed fertilizer, avoid contact with seeds and fertilizers, and control the dosage.
Third, it is not appropriate to apply water immediately after application. Urea is an amide nitrogen fertilizer, which can be converted into ammonia nitrogen to be absorbed and utilized by crop roots. The transformation process varies depending on soil, water and temperature, and the time is long and short. Generally, it takes 2 to 10 days to complete. Immediately after irrigation or dry land is applied before heavy rain, urea will dissolve in the water and be lost. Generally, summer and autumn seasons should be watered 2 to 3 days after application, and water should be watered after 7 to 8 days after application.
Fourth, it is not appropriate to spread the table. Urea is applied to the surface and can be used after 4 to 5 days of transformation at room temperature. Most of the nitrogen is easily volatilized during the ammoniation process. The actual utilization rate is only about 30%, if it is in alkaline soil and organic matter content. When the soil is applied in high soil, the loss of nitrogen will be faster and more. Moreover, the shallow application of urea is easy to be consumed by weeds. Deep application of urea, melt fertilizer in the soil, so that the fertilizer is in the moist soil layer, is conducive to the performance of fertilizer. For the topdressing should be applied to the seedlings or the ditch on the side of the seedling, the depth should be about 10~15cm. In this way, urea is concentrated in the dense layer of the roots, which is convenient for crops to be absorbed and utilized. Tests have shown that deep application can increase the utilization rate of urea by 10% to 30%.
Fifth, it should not be used too much. Urea has a high nitrogen content, and the application rate should not be too large, so as to avoid unnecessary waste and "fat damage". Generally, 5 to 15 kg per mu is applied, and 15 to 20 kg per acre is applied to the paddy field. Excessive application, can not be absorbed by the soil before conversion to ammonium bicarbonate, easily leached by rain, and easily damage crops. At the same time, too much urea is applied, most of which is lost, and entering the groundwater will cause nitrogen pollution in the water body, causing the deposition of nitrite, which seriously affects the safety of humans and animals.
Sixth, it is not suitable for high-concentration foliar application. Among all nitrogen fertilizers, urea is the most ideal foliar fertilizer. Spraying urea, the amount and speed of protein synthesis in crops exceeds that of other nitrogen fertilizers. However, when the foliar spray is applied, the concentration of the urea solution should not be too large, otherwise the leaves will be burned and the plants will be poisoned. Generally, the concentration of spraying on corn, rice, etc. is preferably 2%; vegetables and melons are preferably 0.5% to 1.5%.
Seven, it is not appropriate to apply too late. The application of urea is too late, which is not conducive to the exertion of fertilizer efficiency, and it is easy to cause crops to be late and mature, so it should be applied 4 to 7 days earlier than other nitrogen fertilizers.
Eight, should not be applied to celery. During the whole growth period of celery, a large amount of nitrogen fertilizer should be applied, but urea cannot be applied. Because the application of urea will increase the celery fiber to thicken, the plant aging, slow growth, and bitter taste when eating, the quality is inferior.
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