After the “early winter†has passed, the harvesting of citrus fruits is completed, and the timely application of good winter fertilizers is of great significance to the healthy reproduction of citrus trees to ensure stable production, high quality and high yield. Winter fertilizer after fruit harvesting is also a citrus base fertilizer, and the amount of fertilizer should account for 50%-70% of the total annual fertilization amount. The significance of Shi Dong Fei is mainly: (1) The consumption of too much nutrients after the high yield of citrus plants needs to be supplemented. (2) The organic fertilizer applied to soil slowly decomposes under the action of microorganisms, which is beneficial to the gradual absorption and utilization of citrus in the winter when the growth is slowed and the root absorption capacity becomes weak, so that more organic nutrients are accumulated in the tree body. For the budding flowering needs in the coming year. (3) The orange tree after fruit picking can be restored as soon as possible. (4) It has a good leaf protection function, prolongs the life of the leaf, and prevents citrus winter deciduous. (5) It is conducive to stable production and high quality of citrus trees. (6) greatly enhance the antifreeze and drought resistance of orange trees. Shi Dong Fei should be dominated by organic fertilizers. Each adult orange tree should be rotted with 100--200 pounds of manure, 100-200 pounds of mature turf soil, 3 pounds of cake fertilizer, 4 pounds of phosphate fertilizer, 3 pounds of potash fertilizer, and 3 limes. - 4 pounds, can also be applied in the application of crop manholes, garbage, pond mud and other organic fertilizers, apply 3 pounds of cooked beans, 3 pounds of dried cakes, 3 pounds of phosphate fertilizer, 1 pound of urea, 3 to 4 pounds of lime. The main fertilization methods are as follows: (1) Excavating arcs or ring-shaped deep trenches along the canopy, the depth of the trench is about 50 centimeters. The width of the trench depends on the amount of fertilizer, and the excavated roots are cut. During the trenching process, the surface layer and subsoil should be stacked separately, and organic manure such as manure, turf, and dried cakes should be applied to the lower layer, and nitrogen fertilizer should be placed on the upper layer. The leaves with dark green color or large amount of fruit should be properly increased with phosphorus and potassium fertilizers. The declining tree should increase the available nitrogen fertilizer appropriately. In the ditch, first fill in more fertile topsoil and fill the subsoil with the surface. (2) Radial trench fertilization. According to the size of the canopy, 4--6 radial sulci were opened along the direction of horizontal root growth. The sulcus was shallow near the main trunk and deeper toward the crown projection. Using this method, the fertilizer distribution surface is wider than that of the ring-shaped groove, and it is possible to change the fertilization site, enlarge the fertilization surface, and promote root absorption every other year, which is particularly suitable for adult citrus orchards. The application of winter fertilizer was completed at the latest by mid-December. In the cold before the advent of the best two can be top dressing, spraying 0.4% urea plus 0.3% potassium dihydrogen phosphate and other effects better.