The roots of apple trees are mainly distributed in 0-40 cm soil layers. There are two peaks in the growth of root system during the year, and autumn is the second growth peak. Into the fall, you need to make a reasonable top dressing of apple trees. The absorption characteristics of apple trees are: nitrogen is predominant in the early stage, and potassium is the main component in the middle and later stages. Absorption of phosphorus is relatively stable throughout the year. Therefore, fertilization should pay attention to the following points:
1. According to the yield load, the proportion of fertilization should be balanced. The ratio of apple to nitrogen, phosphorus and potassium is 1:0.5:1. In general, 0.8 kg of nitrogen, 0.4 kg of phosphorus, and 0.8 kg of potassium are required for every 100 kg of fruit produced.
2. Autumn is the late growth period of fruit trees. Potassium fertilizer is the main factor to promote fruit enlargement and sugar accumulation and improve quality.
3. Grasp the timing of fertilization. In autumn, after the fruit is harvested, the root growth peak comes at the time of applying the base fertilizer, preferably after the autumn shoots stop growing. The northern region is mostly from September to October.
4. Organic manure, chemical fertilizers and extra-fertilizer combined application. Organic fertilizer is generally used as a base fertilizer, and cattle and sheep manure and chicken manure are all available. The total amount of fertilizer, the amount of cattle and sheep manure to "pound fruit Jinfei" is appropriate, chicken manure can be halved, according to the total fertilization in autumn, for the lack of spring fertilization, supplement the amount of fertilizer and fertilizer types.
Pay attention to the location and depth of fertilization. Under normal circumstances, ring, semi-annular groove applies to saplings. The ditch, acupuncture, radiation trench fertilization method and garden spreading method are mostly used for adult trees. The depth of fertilization is generally about 40 cm. With the expansion of the tree crown, the scope and depth of fertilization should also be increased accordingly. It is advisable to apply it to the main distribution layer of the root system.
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