What kind of fertilizer does sugar orange grow best and the fruit is sweetest?

(1) Essential mineral nutrition of Shatangju:

There are 12 mineral nutrients necessary for Shatangju: nitrogen, phosphorus, potassium, (macroelements), calcium, magnesium, sulfur (macroelements), zinc, manganese, iron, copper, boron, molybdenum and (trace elements). Every nutrition has a certain function, and the lack of any nutrition will affect the growth of citrus; On the contrary, if some nutrients are too much, they will also have toxic effects. On the other hand, various nutrients have their inherent proportions and interactions. If the proportion is unbalanced (especially trace elements), there will be bad symptoms, which will affect the yield or quality. These nutrients can be supplemented by applying various fertilizers (organic fertilizer and inorganic fertilizer).

(2) Fertilization period of fruit trees: Generally, fruit trees are fertilized 4-5 times a year.

1. Spring bamboo shoots fertilizer: it is applied about 20 days before the spring bamboo shoots germinate (usually in February), and the available nitrogen fertilizer is the main one. However, young and strong trees and early fruit trees should be "fertilized in bud" according to the amount of flowers, so as to control the length of spring shoots and easily protect fruits. You can sprinkle lime powder to neutralize soil acidity, or spray some foliar fertilizer. Such as spraying 0. 15% borax, 0.3% magnesium sulfate, 0.3% potassium dihydrogen phosphate, 0.3% urea, nutritional nucleotides, etc.

2. Small fruit fertilizer for flowering: applying compound fertilizer and urea at the beginning of flowering, applying more fruits and less fruits can significantly improve the fruit setting rate. Generally, the yield per plant is 25 kg, and it is appropriate to apply 0.2-0.4 kg compound fertilizer per plant. However, attention should be paid to controlling the germination of summer buds. Provide nutrients to young fruits in summer shoot stage, and apply topdressing outside the roots.

3. Fertilization of autumn shoots: The cultivated mother shoots are the focus of fertilization in one year, which should account for 30%-40% of the total fertilization in the whole year. The fertilizer is mainly available nitrogen fertilizer, which can be combined with decomposed organic fertilizer and applied 10-20 days before bamboo shoots are released. Fertilization should be combined with irrigation to make the autumn shoots vomit together. If you bury dried peanut bran or dried chicken manure, you should generally attack the autumn shoots 40-60 days in advance. A small amount of autumn shoot fertilizer can also be used as strong shoot fertilizer after autumn shoots germinate or turn green.

4. Flower bud chemical fertilizer: Generally, it is applied before flower bud differentiation in June 5438+065438+ 10, and it is mainly buried with soil mixed fertilizer, organic fertilizer or compound fertilizer, which is mainly used to promote flower bud differentiation of citrus.

5. Fertilizers before (after) harvest: old trees, weak trees, many fruit trees, late-maturing species (bananas and oranges, etc.). ) Quick-acting fertilizer can be applied once before or after the fruit is harvested, so as to promote the early recovery of the plant and reduce the defoliation in winter, which is beneficial to the differentiation of flower buds. Young trees and strong trees can't apply this fertilizer. After the fruit is picked, the whole garden is covered with soil once, especially for citrus with shallow roots, which is beneficial to protect the root group from overwintering and increase the nutrient area and fertilizer content.

(3) Fertilization amount and method:

Fertilization amount: It varies with soil, variety, tree age, fruit yield and climate. This is complicated. Generally, 30-35 kg of nitrogen is applied to the first fruit-bearing tree every year, and 8- 10 kg/100 kg of pure nitrogen is applied to the full fruit-bearing tree every year, and organic fertilizer accounts for a certain proportion. The ratio of fertilizer nitrogen: phosphorus: potassium = 1: 0.2-0.3: 0.7- 1. According to the above calculation, peanut bran 125- 150 kg, urea 20-25 kg, compound fertilizer 30-40 kg and potassium chloride 25-30 kg should be applied per mu in orchards with high yield of 2,500-3,000 kg. Fertilization method: Water and fertilizer made of human and animal manure and peanut bran must be fully decomposed before application, and some of them are buried deeper. Liquid fertilizer or chemical fertilizer should be applied in the shallow ditch under the crown drip line, covered with soil after application, and pay attention to the position of rotary fertilization.