1. Planting: Pomelo trees like to be warm and humid, need rich water, and the soil layer is deep and fertile. Pomelo trees should pay special attention to planting in places with fertile soil and sufficient water or in places with good water resources. 1, planting time. Generally suitable for spring and autumn rainy season, from the end of February to the end of April in spring; Autumn from mid September to mid June 10. It can be planted in other seasons if conditions permit, but it is not suitable for dry planting in late winter and summer. 2. Planting density. The plant spacing is 4x4m or 4x5m, generally about 40 plants per mu, or 50-60 plants per mu can be dwarfed and densely planted. 3. Planting method. (1), dig a pit 1 m square before planting, apply a large amount of head fertilizer and a proper amount of phosphate fertilizer as base fertilizer, and return the soil to 20-30 cm above the ground. (2) When planting, gently put the seedlings into the holes, plant them with loose soil, and compact the fine mud around the root groups by hand, so that the joints are exposed to the ground. (3) After planting, arrange the trays 20 cm above the ground and fill them with root water.

Second, soil cultivation: 1, digging and expanding holes, and soil curing. Deep ploughing, soil improvement and soil maturation must start from the establishment of the garden and expand year by year. Young trees can dig circular ditches around the plants and plough deeply in different years. Adult pomelo orchards can be ditched about 0.5-0.7 meters around the crown, and organic fertilizers such as green manure and inorganic manure can be buried in layers, and they can also be deepened every other year, alternately every year or at the rotation position of each plant. 2. Plant green manure. Nourish land with land. Covering the ground with green manure can prevent erosion, reduce soil temperature, increase air humidity, inhibit weeds in summer, increase soil organic matter and improve soil fertility. If you intercrop beans and vegetables, you can increase the early benefits, cover the straw and residual branches, turn them into soil seeds and increase soil organic matter. 3. Intertillage and soil cultivation. Weeding is combined with intertillage, usually 3-4 times a year, that is, after picking fruits in winter, sowing and intercropping are combined once in summer or autumn. Planting depth 10- 15cm (combined with intercropping and sowing, appropriately deepened). The closer to the trunk, the shallower it is, so as not to lose the big roots. The soil should be cultivated before the dry season or after picking fruits in winter. In gentle slope areas, the soil should be cultivated once every 3-4 years, and in places with large slope and serious erosion, it should be cultivated once every other year.

Third, fertilization. Young trees are small and tender, so they should be applied thinly and frequently, and can be applied 5-6 times a year. Generally, it is necessary to apply fertilizer four times to the bearing trees, that is, rejuvenation fertilizer, accelerating germination fertilizer, stabilizing fruit fertilizer and strengthening fruit fertilizer. 1. Returning fertilizer (base fertilizer): It should be applied before and after fruit picking, and its fertilization amount accounts for half of the annual fertilization amount. Slow-acting fertilizers, such as green manure, compost, manure and cake fertilizer, should be applied in large quantities, accompanied by quick-acting nitrogen fertilizer and phosphorus fertilizer. 2. Germination-accelerating fertilizer (fertilizer before flowering): usually carried out in February-March. This kind of fertilizer should be mainly available nitrogen fertilizer, mainly human and animal manure, and properly combined with urea. 3. Fruit-stabilizing fertilizer: quick-acting nitrogen fertilizer and phosphorus fertilizer can be applied in the first half month of fruit dropping in June, decomposed human and animal manure can be applied, and calcium superphosphate 1% leaching solution can be sprayed. 4. Strong fruit fertilizer: applied in the middle and late June, with available nitrogen fertilizer and phosphorus and potassium fertilizer.

Four. Irrigation and drainage. Pomelo trees are evergreen all the year round, with large annual growth of branches and shoots, long fruiting period, large leaves and fruits, and high requirements for water. The cultivation of pomelo trees must ensure their water demand through irrigation, which should be based on the water demand of pomelo trees in the later period and the drought situation at that time. Generally speaking, its growth and development process needs a proper amount of water all year round, especially in the spring bud germination, flowering period and fruit growth peak period, when it encounters spring drought and summer drought, it must be irrigated. Pay attention to drainage in places with low terrain and high groundwater level or in rainy season. Before rainy season or rainstorm season, check the drainage system of pomelo garden at any time, and timely repair and dredge it to ensure smooth drainage.

Fifth, plastic trimming. The grapefruit tree is strong and tall. When young, under the condition of sufficient fertilizer and water, the top has strong advantages, the branches grow upright, and it is easy to form an obvious trunk tree shape, and the new shoots are numerous and strong. After the fruit, the branches droop and bend downward, making the tree form an umbrella. Light is not easy to penetrate into the canopy, but the branches are small. The fruiting branches of pomelo trees are mostly in the crown, which are biennial leafless branches (commonly known as claws). According to the growth and fruiting characteristics of pomelo trees, it is appropriate to choose "lateral stem shape" and "natural happy shape" in production, with stem height of 40-60 cm and main branch spacing of 30-40 cm, and cultivate 5-6 main branches. When pruning pomelo trees, it should be "heavy on the top and light on the bottom, light on all sides, heavy on the periphery and light on the inside", that is, thinning the dense branches around the crown, heavy pruning on the top branches and light pruning on the internal branches, so that the light inside the crown is good, and there are many fruits and good quality. Generally, the slender leafless branches on the 3-4-year-old side branches in the crown are excellent fruiting mother branches and must be preserved. The side branches that are too long or disturb the tree shape around the crown and affect the balance of tree potential should be thinned to achieve the purpose of ventilation.

Six, pest control. There are many pests and diseases that harm pomelo trees, such as mites, scale insects, liriomyza sativae, anthracnose and so on. Control should be based on the occurrence characteristics of various diseases, combined with spray control. 1. Before flowering, spray pesticides twice continuously from the end of February to the beginning of April, mainly to control mites. At the same time, combined with other pests, use pesticides: insecticide+acaricide+bactericide. 2. The young fruit period after flowering is from mid-May to late June.