The eutrophication of the moderate tree in the middle Yongyang tree had higher chlorophyll content, soluble solids content, and fruit coloring index than those of the virgin and weak trees. When the ratio of the thickness of the stem branches and the result branches is 1:4, the fruits are large and well colored; when the ratio of the thickness of the stem branches and the result branches is greater than 1:3, the heads of the fruits are large, but The coloring is poor; when both the backbone branches and the result branches are weak, not only the size of the fruit is small, but also the coloration is not normal. Therefore, maintaining the moderate tree posture is of utmost importance to the production of Red Fuji with full-flavored fruit. Maintaining sufficient light in the crown Red Fuji apples are very sensitive to the light response. Fruit on each branch gets full red when it gets more than 70% of full sun, and when it gets 40% to 70% of full sun, the fruit surface is partially red. The fruit surface is not colored when the sunshine is less than 30%. In order to ensure that the tree has sufficient light conditions, it is necessary to change the weight of the winter cut to the heavy summer cut. In winter, when it is cut, it should be stretched and stretched vigorously, and Wang branches should be laid. Do not cut more than the amount of trees, and the amount of mu branches should be kept between 80,000 and 100,000 pieces. When cutting in the summer, care should be taken to do a good job of brushing the buds from April to May and removing the sprouts from May to June and topping, twisting, and cutting around from late May to early June. Regardless of the type of tree to be trimmed, the main branch should be low, the level should be low, the angle should be large, and the following vertical branch should be the main branch, so as to ensure the ventilation and light transmission of the canopy, and the coloration of the fruit would be bright. Control of leaf mineral content In July, when the nitrogen content of the leaves of the Red Fuji apple tree was greater than 2.5%, the petiole was green and the fruit was difficult to color; when the leaf nitrogen content was less than 1.5%, the petioles and veins were purple, and the fruit was Light coloration is light; When the leaf nitrogen content is about 2%, the petiole is purple, the leaves are dark green, and the fruit is well colored. After August, it is not advisable to pursue nitrogen fertilizer before fruit harvest. At this time, 0.012% of potassium fertilizer can be topdressed, and potassium content of leaves is 0.5% to 0.8%. When the full moon shines up to 70%, the red Fuji apple fruit surface can be achieved. All red. Other technical measures 1 Moderate irrigation. In the early stages of fruit development, a certain amount of water and fertilizer should be maintained, and in the middle period, a certain amount of soil moisture should be maintained, and water should be controlled later. Post-climate irrigation can be achieved if the weather is indeed dry. 2 In early summer and late autumn, tree trays cover grass, which can protect the roots of fruit trees, enhance the absorption capacity of the surface roots, and have obvious effects of increasing sugar, increasing color, and improving fruit flavor. 3 pick leaves, transfer fruit, hanging sticks. Twenty days before the fruit is harvested, the leaves that are shaded and attached to the fruit surface around the fruit can be removed, and the coloring index can be increased by about 15%. 4 to 5 days after picking the leaves, gently hold the fruit by hand to turn the yin to the sun's surface so that it can see the light back and forth and increase the coloring index by about 20%. The pillars and hanging sticks should be erected in a timely manner in the late fruit growth period so as to prevent the fruits from being stained due to sagging, squeezing, overlapping contact with the ground. 4 The spraying of 500 mg/kg rare earth solution when the fruit is near to coloring can make the coloring of the Red Fuji apple 12 to 17 days earlier, the coloring index increases by 24.2%, and the whole red fruit rate increases by more than 5%.