What are the fertilizer requirements of apple trees?
What are the fertilizer requirements of apple trees? Please explain that for apple trees, nitrogen uptake during the year usually has 2 peaks. The first peak coincides with fruit development and the growth of branches and leaves, that is, as young fruit and new shoots grow rapidly, the demand for nitrogen becomes greater and greater. When shoots form in July to August, the whole tree...
What are the fertilizer requirements of apple trees? Please explain
For apple trees, nitrogen uptake during the year usually has 2 peaks. The first peak coincides with fruit development and the growth of branches and leaves, that is, as young fruit and new shoots grow rapidly, the demand for nitrogen becomes greater and greater. When shoots form in July to August, the leaf area of the whole tree reaches its maximum, and the nitrogen requirement also reaches its highest peak. It is currently believed that for non-bearing young apple trees, applying 0.075-0.25 kg of pure nitrogen per tree per year, equivalent to 0.63-0.54 kg of urea, is the optimal fertilizer rate; for trees beginning to bear fruit, 0.25-0.5 kg, equivalent to 0.54-1.1 kg of urea; for trees in full bearing, 0.5-1 kg, equivalent to 1.1-2.2 kg of urea; for large trees in full bearing, 1-1.5 kg, equivalent to 2.2-3.2 kg of urea. However, it must be combined with phosphorus and potassium fertilizers to achieve the best effect. The application rate of phosphate fertilizer can be compared with the annual amount of nitrogen fertilizer, calculated as active ingredients, reaching half the amount of nitrogen fertilizer. For example, if the nitrogen fertilizer rate for a tree beginning to bear fruit is 0.5 kg of pure nitrogen per tree for the whole year, equivalent to 1.1 kg of urea; applying phosphate fertilizer then requires 0.25 kg of pure phosphorus (calculated as phosphorus pentoxide). If the available phosphorus in superphosphate is 11%, then each tree needs 2.3 kg of superphosphate. The results of multi-point trials by the national apple chemical fertilizer trial network believe that the nitrogen, phosphorus, and potassium application ratio for high-yield orchards of mature trees is best at 2:1:2, and for the young tree stage, 2:2:1 is best. This shows that young trees need relatively less potassium and more phosphorus; while the older the bearing tree (the more fruit it bears), the greater its demand for potassium, and it should at least not be lower than the application level of nitrogen. Orchards should also apply organic fertilizer, and this should be maintained once a year. The application rate follows the principle of one jin of fertilizer per jin of fruit, applied once at the end of September or early October each year together with deep digging and hole expansion. If the whole orchard has already been deeply dug once, apply it below the outer edge of the canopy. The organic fertilizer applied must be pre-composted.
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