Pomelo trees like warm and humid, need rich water, and require deep and fertile soil. Pomelo trees should pay special attention to planting on land with thick soil and sufficient water or in places with good water resources.
1, planting time
Generally speaking, the rainy season in spring and autumn is suitable. Spring from the end of February to the end of April; Autumn from mid September to mid June 10. If conditions permit, it can be planted in other seasons, but it is not suitable for planting under low temperature in winter and drought in summer.
2. Planting density
The plant spacing is 4× 4m or 4× 5m. Generally, about 40 plants can be planted per mu, or 50-60 plants can be planted in short density.
3. Planting method
(1) Before planting, dig a pit 1 m square, apply a large amount of organic 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 fine soil, and compact the fine mud around the root groups by hand to expose the joints to the ground.
(3) After planting, arrange the nest plates 20 cm above the ground and fill them with root water.
Second, soil farming.
1, dig deep to expand the pit and solidify the soil.
Deep ploughing, soil improvement and soil maturation must start from the establishment of the garden and expand year by year. Young trees can dig annular ditches around the planting holes and plough deeply in different years. Adult pomelo orchards can be ditched and ploughed around the crown, with a depth and width of about 0.5-0.7 meters. Organic fertilizers, such as green manure and inorganic manure, can be buried in layers, ploughed deeply every other year, alternately every year or in the rotation position of each plant.
2. Plant green manure to support the 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, turn the straw and residual branches into the soil and increase the soil organic matter.
3. Intertillage and soil cultivation.
Weeding is combined with intertillage, usually 3-4 times a year, that is, after fruit is picked in winter, it is combined with sowing and intercropped once in summer or autumn. The depth of intertillage is 10- 15 cm (combined with intercropping and sowing, it should be deepened appropriately), and the closer it is to the trunk, the shallower it is, so as not to damage the big roots. The soil should be cultivated before the dry season comes or after the fruits are picked 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 it is advisable to apply thin fertilizer frequently, which can be applied 5-6 times a year. Generally, it is necessary to apply fertilizer four times to the fruit-bearing trees, that is, returning 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, together with quick-acting nitrogen fertilizer and phosphorus fertilizer.
2. Germination accelerating fertilizer (pre-flowering fertilizer): 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 each phenological period and the drought situation at that time. Generally speaking, the growth and development of Hejiang need a proper amount of water, especially in the spring bud germination period, flowering period and fruit growth peak period. Hejiang is dry in spring and dry in summer, so irrigation must be carried out at this time.
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.
Five, plastic pruning
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, light on the four sides, heavy on the periphery and light on the inside", that is, pruning around the crown is sparse, then pruning the top branches and lightly pruning 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. If the tree is strong, it should be cut down again, and if it is weak, it should be cut down lightly.
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 pests and diseases, combined with pesticide application.
1. From the end of February to the beginning of April before flowering, spraying pesticides twice continuously, mainly to control mites, and combining with other pests, using pesticides: insecticide+acaricide+bactericide.
2. During the young fruit period from mid-May to late June after flowering, chemical agents were sprayed twice continuously, mainly to control scale insects, and at the same time, combined with other pests, pesticides: pesticides+fungicides were used.
3. In autumn, from mid-July to early September, spraying pesticides continuously for 3-4 times, mainly to control leaf miner, butterfly and anthracnose, using pesticides: insecticide+bactericide.
The second peak of mite damage is from mid-September to1early October. Spray 1-2 times to kill mites and treat other pests and diseases, and use pesticides: insecticide+acaricide+bactericide.
Spray a mixture of lime and sulfur to clean the garden in winter.
Insecticides can be used interchangeably, such as chlorpyrifos, trichlorfon and mirex. The bactericide can be selected from any one of carbendazim, thiophanate and zineb. And acaricide can be sprayed alternately, evenly and thoughtfully.
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