Priority should be given to the higher price of urea in major crops, and crops with larger planting areas and higher economic value (such as wheat and corn) should be considered first when applying them. For secondary crops such as buckwheat, appropriate application may be made based on economic conditions. Do not give full play to the role of fertilizer production. As basal fertilizer or topdressing urea is suitable for base fertilizer and top dressing, generally not for seed fertilizer. Because the high concentration of urea can destroy the structure of the protein and cause the protein to deteriorate, affecting the seed germination and the seedling root growth, the seed will lose its ability to germinate when severe. Autumn fallow urea applied to the fall of the spring planting effect is better. Under the same conditions, according to the test, the utilization rate of urea can be increased by more than 10.8% over the spring season. If organic fertilizer and other fertilizers are used, the effect is better. The top-dressing urea is amide fertilizer. It is organic, neutral, and contains no accessory ingredients. It has very small burns to stems and leaves of crops. Urea has a small molecular size and easily penetrates into the cell membrane. Urea itself is hygroscopic and can easily be used as a leaf. Absorption, when urea penetrates into the leaves, causes less plasmolysis, and will recover quickly even if it occurs. So urea as top dressing is better than other nitrogen fertilizers. The concentration and time of spraying outside the root differ with the type of crop. Generally, the use of urea is 0.5-2.5 kg per acre, once every 4-5 days, 2-3 times. The application of urea to the soil in advance is first performed by the soil microorganisms, and finally it is hydrolyzed to ammonium carbonate or ammonium bicarbonate before it can be absorbed by the crop roots. The final product of deep-buried urea decomposition in soil is ammonium carbonate. Ammonium carbonate is very unstable and decomposes into free ammonia in the soil or on the surface of the soil to form volatile free ammonia. Therefore, urea must be deeply applied to cover soil, and the depth of earth covering is generally about 10 cm. . After the rain, the urea has good hygroscopicity, and the topdressing in the dry land is as far as possible after the rain so that the fertilizer dissolves quickly and is absorbed by the soil. At the same time, some fertilizers can also be absorbed through the leaves to increase fertilizer efficiency and reduce losses. The application of urea in the morning or evening is the same as in other nitrogen fertilizers. The application time of urea should be in the morning or in the evening. It is best to use it after rain or cloudy days. Avoid use at sunny noon. The application of urea in combination with other chemical fertilizers is a unit fertilizer, which should be used in combination with phosphate fertilizers or other fertilizers. This can meet the needs of crops for various nutrients and can also play a role in assisting fertilizers. The application of urea and organic fertilizers in conjunction with organic fertilizers is an effective measure to increase the efficiency of urea fertilizers. It can be used to complement each other's strengths, improve efficiencies, save fertilizers, promote microbial activities, improve crop nutrient conditions, reduce production costs, increase production, and increase income. Etc., thereby increasing the economic efficiency of fertilizers. Farmyard manure is best with high quality pig manure, and the urea pig manure ratio is 1:1.9. Source: "China Cooperation Times"