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1. It is recommended to combine the soil testing formula and determine the nitrogen application rate of nitrogen application rate (crop nitrogen requirement-soil nitrogen supply)/nitrogen utilization rate in fertilizer by nutrient balance method, among which: crop nitrogen requirement = target yield ( Kg.hm-2) × nitrogen uptake per unit of yield (kg) soil nitrogen supply = soil available nitrogen value (mg.kg-1) × 2.25 × soil nitrogen use coefficient Nitrogen utilization rate in fertilizer = nitrogen in fertilizer Prime content × nitrogen utilization rate of the season × 100%.
Second, attach importance to the balanced fertilization crops have a certain proportion of the demand for various nutrients. Therefore, chemical nitrogen fertilizer must be applied in combination with phosphorus and potassium fertilizers, organic fertilizers and chemical nitrogen fertilizers should be applied together, and according to the different demand laws of nutrients in each growth period of crops, Implement balanced fertilization.
Third, adhere to a reasonable method of nitrogen application The main ways of nitrogen loss, nitrogenation, denitrification, leaching and runoff. Therefore, attention should be paid to the application of nitrogen: 1. Adhere to the principle of “deep application of soilâ€, ammonium When nitrogen fertilizer and urea are used as base fertilizer, the application of deep application combined with ploughing and overturning soil can be used to reduce the evaporation of ammonia by utilizing the adsorption capacity of the soil. When doing topdressing, it should be applied by acupoint application, ditch application or combined with irrigation. In order to overcome the delay of fertilizer effect that may occur in deep application of nitrogen fertilizer, the application time should be appropriate several days in advance, and the amount should be reduced as appropriate in the middle and late stages of topdressing. 2. Avoid the leaching and denitrification of nitrate nitrogen. The nitrate nitrogen fertilizer is applied to paddy fields. Generally, it is not used as base fertilizer. After topdressing, large water should be avoided, and the rainy season should be applied as little as possible or not. Avoid simultaneous application with large amounts of unfermented organic fertilizer to avoid loss of nitrate nitrogen and denitrification. 3. Using a reasonable water and fertilizer comprehensive management of rice fields to promote the “drip with water†deep application technique, that is, before the fertilization, the rice fields stop watering, drying the fields for several days, controlling the water to stabilize the roots and promoting the absorption of nitrogen. As far as possible, the soil is in an unsaturated state. The nitrogen fertilizer is re-shallowed immediately after application, so that the fertilizer is infiltrated with water and deeply applied to the soil, so that the fertilizer efficiency is slow, stable and long.
How to apply nitrogen fertilizer scientifically
The largest amount of fertilizer needed in production, which plays an important role in improving crop yield and improving the quality of agricultural products. However, too much nitrogen and imbalance of nutrients often cause crops to grow in the middle and late stages, and the resistance to stress is weakened, which leads to a decline in yield and a decrease in quality. Therefore, nitrogen fertilizer should be applied scientifically:
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