One should be mixed with alkaline fertilizer or applied at the same time. Alkaline fertilizers include plant ash, lime, molybdenum, magnesium phosphate, etc., such as mixed urea or simultaneous application, will increase the nitrogen in the urea into ammonia and volatilize. Therefore, in summer and autumn, urea and alkaline fertilizer should be staggered for 3-4 days, and winter and spring should be staggered for 7-8 days.
Two bogey for mixing fertilizer. Urea is used as a seed fertilizer to make the seeds lose their germination power and can also endanger the seedlings. At the same time, because high concentration of urea can destroy the protein structure of the seed, it is also toxic and inhibiting to the seed, 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.
Use water immediately after the application. The amide nitrogen has a low adsorption capacity with the soil colloid, and its fluidity and loss in the soil is not less than that of nitrate nitrogen. Therefore, after applying urea, do not water before the conversion is completed, otherwise the waste will be wasted. Generally, summer and autumn seasons should be watered 2-3 days after application, and winter and spring seasons should be watered after 7-8 days after application. After the application, the ploughing will make the soil and fertilizer melt together, and urea cannot be applied before the heavy rain.
Four bogey shallow application. Urea is easy to use and is easily 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 10-15 cm. In this way, urea is concentrated in the root dense layer, which is convenient for crop absorption and utilization. Tests have shown that deep application can increase the utilization rate of urea by 10-30% compared with shallow application.
Five bogey usage is too large. 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, 5-15 kg per mu is applied, and 15-20 kg per mu is applied to the paddy field. Excessive application, can not be absorbed by the soil before being converted to ammonium bicarbonate, easily lost by rain, and easily damage crops.
Six bogey high concentration foliar application. Foliar spray should avoid excessive concentration of urea solution, otherwise it will burn out the leaves and poison the plants. Vegetable melons should be 0.5-1.5%.
Seven bogey is applied too late. The application of urea too late is not conducive to the exertion of fertilizer efficiency, and it is easy to cause crops to be late and ripe, so it should be applied 4-7 days earlier than other nitrogen fertilizers.
Eight bogey single application. The active ingredient of urea is nitrogen, and the growth and development of crops requires multiple nutrients. Urea should be applied in combination with organic fertilizers and phosphorus and potassium fertilizers to meet the needs of crops for various nutrients. It can also accelerate the conversion and decomposition of urea, and is quickly absorbed by crops to improve the utilization of urea.
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