Urea nitrogen 46%, is the use of more quality chemical nitrogen fertilizer in rural areas. According to the author's understanding, some peasant friends are still unclear about the nature of urea, and there are still six misunderstandings in use. Misunderstanding 1: Urea mixed with ammonium bicarbonate. Since urea is applied to the soil, it must be converted into ammonia before it can be absorbed by the crop. The conversion rate is much slower under alkaline conditions than under acidic conditions. After ammonium bicarbonate was applied to the soil, the reaction was alkaline and the pH was 8.2-8.4. Mixed application of ammonium bicarbonate and urea in farmland will greatly reduce the rate of conversion of urea to ammonia, which will easily lead to loss of urea and loss of volatiles. Therefore, urea and ammonium bicarbonate should not be mixed or applied simultaneously. Misunderstanding 2: Surface spread. Urea is applied to the surface of the earth. At room temperature, it takes 4-5 days for transformation to be absorbed by the crop. Most of the nitrogen is volatilized during the ammonium process. The utilization rate is only about 30%. If the alkaline soil and organic matter are high The application of soil, nitrogen loss faster and more. Therefore, nitrogen cannot be spread on the surface. Myth 3: Urea as a fertilizer. In the production process, urea often produces a small amount of biuret. Biuret content of more than 2% will poison seeds and seedlings. Urea enters seeds and seedlings and denatures proteins, affecting seed germination and seedling growth. Misunderstanding 4: Apply water immediately after applying urea. Urea is an amine nitrogen fertilizer that must be converted to ammonia nitrogen before it can be absorbed and utilized by crops. The conversion process depends on the conditions of soil quality, moisture, temperature, etc. The time varies from 2 to 10 days. If urea is applied immediately after irrigation or dry land is applied before heavy rain, urea will dissolve in water and be lost. . Misunderstanding 5: Mixed application of urea and alkaline fertilizers. After urea is applied, it must be converted into ammonia nitrogen before it can be used by crops. Under alkaline conditions, most of the nitrogen in the ammonia nitrogen will evaporate. Therefore, urea cannot be mixed with lime, grass ash, calcium magnesium phosphate, and other alkaline fertilizers or applied at the same time. Misunderstanding 6: Urea is applied to celery. During the entire growth of celery, a large amount of nitrogen fertilizer should be applied, but no urea should be applied. Because of the topdressing of urea, the celery fiber becomes thicker, the plants are aging, and the growth is slow, and the consumption is bitter and the quality is poor. The celery is suitable for applying ammonium bicarbonate, ammonia, and organic fertilizers to improve quality. China Agricultural Network Editor
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