Reasonable suggestions on cultivation and management of pomelo in Dongshi early

   1) soil management. Young orchards should do a good job of ploughing and weeding, interplanting green manure, soybeans and peanuts, deeply turning the soil and cleaning the soil of the orchard.

  ① ploughing and weeding can prevent ground hardening, loosen soil, eliminate weeds and reduce the occurrence of diseases and insect pests. Mid-tillage weeding can be combined with deep ploughing and soil cultivation.

Interplanting green manure, peanut, soybean and white rice bean in   ② orchard can increase soil organic matter and interplant watermelons and vegetables when labor permits, but it is not suitable to grow sweet potato.

  ③ deep ploughing soil: make sure there are beds and ditches, clean the orchard, thoroughly remove diseases and insects, fallen leaves, dead branches, weeds and parasitic plants such as lichens, moss and dodder on the tree trunk, and then burn them.

  ④ reasonable fertilization: because of high crown, thick branches and luxuriant leaves, large fruit, long fruit hanging time and developed root group, fertilizer must be applied to achieve high yield. Organic manure includes manure, stable manure, cake manure, farm manure, soil manure, green manure and so on. Chemical fertilizer should be applied reasonably, and pomelo has a certain demand for magnesium fertilizer, which should be paid attention to when applying fertilizer.

   2) fertilization for young trees. Young trees should pay attention to promoting their vegetative growth and enlarge their crown, and should be based on nitrogen fertilizer, combined with appropriate amount of phosphorus and potassium fertilizer, and can apply thin fertilizer once a month after planting. Generally, they can be fertilized more than 6 times a year and once a month from February to September. Fertilizer is mainly human manure, pig, cow manure, cake fertilizer, etc., combined with the application of urea, calcium superphosphate and so on. According to the concentration of raw fertilizer and the dry and wet condition of the soil, human feces and urine can be added 1 / 2 times of water, and combined with chemical fertilizer, the trenches can be dug at the dripping line outside the canopy on the two sides of the young tree. 2.5~5kg is applied to each tree, urea 50g after rain, bone powder, calcium, magnesium and phosphorus can be applied in spring and autumn, 150g to 250g per plant and mature fertilizer. Then cover and fill it. In the second and third years, due to the gradual expansion of the tree crown, the fertilization concentration can be increased, applying fertilizer 4-5 times in the whole year.

   3) fertilization for adult trees. When pomelo trees enter the fruiting stage, fertilization can not only promote vegetative growth, but also ensure reproductive growth. The time, frequency and quantity of fertilization should vary according to climate, soil, tree potential, yield and so on.

   4) ① for the first time: spring bud fertilizer. One to two weeks before the climate warms up to pomelo germination, usually in early February, mainly available nitrogen and phosphorus, each plant is applied human fecal and urine 30kg, nitrogen fertilizer 0.2~0.5kg, phosphate fertilizer 1kg, accounting for 20% of the annual fertilizer application.

  ② the second time: protect fruit fertilizer. From late April to early May, the excessive consumption of nutrients in pomelo trees was supplemented to reduce fruit drop. Each plant was treated with human fecal urine 20kg, phosphorus and potassium fertilizer 1.5kg, and 1% urea and 2% superphosphate were also used to extract liquid root topdressing, accounting for 10% of the annual fertilizer application.

The third time of   ③: strong fruit fertilizer. It was applied when the fruit was enlarged from June to July. Each plant was treated with human feces and urine 15~25kg, plus 1~1.5kg cake fertilizer, 2kg bone meal and nitrogen fertilizer 1~2kg, accounting for 20% of the total fertilizer application in the whole year.

The fourth time of   ④: fruit-picking fertilizer. From late October to December, all organic fertilizers were applied, combined with phosphorus and potassium fertilizer. Each plant was treated with human feces and urine 25kg, soil fertilizer 50kg, phosphorus and potassium fertilizer 2~3kg, accounting for 50% of the whole year. If there are too many fruits, apply quick-acting chemical fertilizer 10-15 days before fruit harvest, combined with irrigation.