Give priority to the main crops. The price of urea is relatively high. In the application, crops with larger planting areas and higher economic value (such as wheat and corn) should be considered first. For buckwheat and other minor crops, they can be appropriately applied or not applied according to economic conditions. Give full play to the role of fertilizer production. As base fertilizer or top dressing. Urea is suitable for basal fertilizers and top dressings, and is generally not used as a seed fertilizer. Because the high concentration of urea can destroy the structure of the protein and make the protein deteriorate, affecting the seed germination and the seedling root growth, the seed will lose its ability to germinate when severe. Fall and fall fertilizer. Urea application in autumn is better than that in spring. 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. As top-dressing fertilizer. Urea is an amide fertilizer, is organic, neutral, does not contain accessory components, and has minimal burns to the stems and leaves of crops; urea has a small molecular size and easily penetrates the cell membrane into the cells; urea itself is hygroscopic and can be easily absorbed by the leaves. When the leaves penetrate, there are few cases of plasmolysis, and even if they happen, they will recover quickly. So urea as top dressing is better than other nitrogen fertilizers. The concentration and time of spraying outside the root varies with the type of crop. Usually 0.5-2.5 kg of urea per acre, once every 4-5 days, 2-3 times. Follow up early. Urea is applied to the soil and it is first subjected to the action of microorganisms in the soil, and finally it is hydrolyzed to ammonium bicarbonate before it can be absorbed by the crop roots. Deeply cover soil. The final product of urea decomposition in the soil is ammonium carbonate. Ammonium carbonate is very unstable, and it is decomposed in the soil or soil surface to form free ammonia, which is easy to volatilize. Therefore, urea must also be deeply applied to cover soil, and the depth of cover soil is generally about 10cm. Apply after rain. The urea has good hygroscopicity and the topdressing in the drylands is as much as possible after 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. Apply in the morning or evening. Like other nitrogen fertilizers, urea application time should be in the morning or evening, preferably after rain or cloudy days, avoid sunny noon. Use with other chemical fertilizers. Urea is a unit fertilizer, which should be used in combination with phosphate fertilizer or other fertilizers to meet the needs of crops for various nutrients, but also to play a role in helping between fertilizers. Applied with organic fertilizers. The combined application of urea and organic fertilizers is an effective measure to increase the efficiency of urea fertilizer, which can be used to complement each other and improve economic efficiency; improve fertilizer efficiency and save fertilizer; promote microbial activities and improve crop nutrient conditions; reduce production costs, increase production, increase income, etc., thereby increasing fertilizers The economic benefits, the best quality of farm manure pig manure, urea pig manure ratio of 1:1.9. China Agricultural Network Editor