First, 1-3 years of fertilization of saplings to accelerate the growth of young trees, early high-yield, should be combined with the characteristics of multiple tips of pomelo and multiple fertilization, hair tips can promote hair tips, so that the shoots grow robustly. Top dressing is quick-acting fertilizer. Fertilization method: apply sparingly, spring shoot fertilizer and more. The fertilization time was 2, 5, and 7 months respectively. If it is desired to start the results in the second year after planting, the phosphorus and potassium fertilizers should be appropriately increased during the autumn shoots to reduce the amount of nitrogen fertilizer. In order to promote flowering, it is possible to spray 0.3% to 0.6% of strong trees during flower bud differentiation (December). % Potassium dipotassium dihydrogen phosphate 2-3 times; Weak tree spray 0.2% Potassium dihydrogen phosphate plus 0.4%-0.5% urea 3-4 times. A large amount of organic fertilizer, green manure, and phosphorus and potassium fertilizers should also be added to lay the upper layer of the ground to promote the development of horizontal roots in order to facilitate early fruit production.
Second, the results of tree fertilization results Tree fertilization is generally divided into four sub-fertilizer, that is, Yang Fei, promote fertilizer, stable fruit fertilizer and strong fruit fertilizer.
1, Yang Fei (base fertilizer). Fertilizing time: before and after fruit harvesting; an important role of fertilization: due to flowering of pomelo tree, the results consume a lot of nutrients, in order to restore tree vigor, promote flower bud differentiation, enrich the results of the mother branch, to ensure that the next year nutrient needs, must apply enough base fertilizer. The amount of fertilizer should generally account for 50% of the annual fertilization amount. The type of fertilizer: green fertilizer, compost, cake fertilizer and other delayed fertilizers, together with the application of available nitrogen fertilizer and phosphate fertilizer (superphosphate is the best). Fertilization method: Excavate the annular groove at the periphery of the crown, phosphate fertilizer is under, and urea is on the top.
2, precipitating fertilizer (before flowering). Fertilization time: 2-3 months; an important role of fertilization: can promote the spring shoots, supply the need for flowering results, lay the foundation for the results of the last year and the results of the next year robust mother tree; can overcome the size of the year, To achieve high yield and stable production. Therefore, fertilization is an important measure to increase production; fertilization types: mainly available nitrogen fertilizers, such as human waste or urea, ammonium sulfate and so on.
3, stable fruit fertilizer. Fertilization time: should be in the second half of the physiological fruit drop (June); important role of fertilization: to compensate for the nutrients needed for flowering and nutrients used in flowering, reduce fruit drop, improve fruiting rate, and ensure high yield; Fertilizer Type: Available nitrogen fertilizer and phosphate fertilizer, can also apply human urine, spraying 1% of superphosphate calcium leachate.
4, strong fruit fertilizer. Fertilization time: before the autumn shoot, from May to June; an important role of fertilization: July-August, the fruit grows quickly, while extracting a large number of autumn shoots, resulting in competition for nutrients and water conflicts; fertilization species: in order to accelerate fruit growth , To improve fruit quality, and at the same time promote the occurrence of autumn shoots, you need to chase application of available nitrogen fertilizer and phosphorus potassium fertilizer. For adult fruit trees, basal fertilizer is generally applied: in February, 150 kg of animal manure is applied to each plant and oil is added at the same time. In May, 100 kg of animal manure is applied per plant; in July, 150 kg of animal manure is applied to each plant, and appropriate superphosphate is added.