In order to color apples in the later stage of growth, potassium needs to be supplemented, so water-soluble high potassium should be applied in late July and early August. But in late August, the basal fertilizer will be applied in autumn, and there is nitrogen fertilizer in the compound fertilizer. There are many people who have this kind of thought, and here are the answers:
Everyone knows that the red Fuji variety is only colored when the temperature difference reaches more than 10 °C, and the color only starts in early September, but potassium supplementation requires early July to early August, and the time is advanced to 30 to 40 days before coloring. This is because the root system has a complex process of absorption, transportation to the tree for synthesis, transformation, utilization, and nutrient redistribution. Only when this process is completed before coloring, the tree has less nitrogen and more potassium, so that more carbohydrates can be synthesized, and the time for coloring can be fast and good. If you add potassium at the time of coloring, it will definitely be too late.
When applying basal fertilizer in autumn, the compound fertilizer has high nitrogen content, which is conducive to improving leaf function, synthesizing more nutrients, and storing it in the tree body for flowering, fruit setting, long branches and leaves next year. Everyone knows that more "nitrogen" is needed before flowering, but according to "Fruit Tree Cultivation", "nitrogen" is needed before flowering, which mainly refers to "ammonia nitrogen synthesized by leaves, and its types are protein nitrogen and amino acids." ”
Of course, some people are worried that the high nitrogen content of the autumn basal fertilizer compound fertilizer will affect the effect of potassium supplementation, in fact, this worry is also superfluous, because compound fertilizer is not like water-soluble fertilizer, water-soluble fertilizer as long as the root system is absorbed, through the root pressure and leaf transpiration of the pull, 6 hours to the various organs on the tree, but the compound fertilizer is applied to the soil, and the cut roots can grow new roots for 15 to 20 days to absorb. Moreover, in addition to nitrogen is an instant fertilizer, phosphorus and potassium are mineral fertilizers. It has been reported that compound fertilizer is not immediately absorbed by the roots when applied to the soil, it has a transformation process, and the length of transformation time is determined by the soil temperature. The soil temperature is 25 degrees, and it takes 4 days for nitrogen to be converted for root absorption; The soil temperature is 15 degrees, and it takes 8 days for nitrogen to be converted for root absorption. The lower the soil temperature, the longer the conversion time, and the phosphorus and potassium conversion time is longer than that of nitrogen.
The water-soluble fertilizer is converted quickly, 6 hours to the tree, and potassium supplementation also needs to be 30~40 days before coloring. The compound fertilizer is slow to convert, and it takes 20 days to grow new roots to absorb nutrients. Moreover, the nitrogen in the compound fertilizer can not be sent to the tree in one day, and the nitrogen can be absorbed in 3~4 months with slow-release fertilizer factors such as long-acting fertilizer and multiple loss control fertilizer. Therefore, the application of basal fertilizer in autumn with more nitrogen will not affect potassium supplementation. The compound fertilizer applied in September is not used up until the leaves are falling, because as the soil temperature drops, the root system will absorb more and more slowly until the root system stops growing. Wait until the soil temperature reaches more than 5°C next spring, and continue to absorb the nutrients from the various fertilizers applied this autumn. Most of the red Fuji apples are harvested in mid to late October, and some are picked in late September and early October. When the fruit is about to be picked, the fertilizer applied in autumn can be connected, and there is no need to worry about the effect of potassium supplementation. In addition, if the basal fertilizer is applied early, the root wound cut off by fertilization has been healed by the time the leaves fall. If the basal fertilizer is applied in spring, the absorption roots are cut off, which is not conducive to flowering and fruit setting, and the branches and leaves are grown. Moreover, the spring application of base fertilizer, due to the low ground temperature at that time, the compound fertilizer also has to grow new roots in dozens of days, transformed, synthesized, and transported to the tree, and when the new shoots want to stop growing, the fertilizer applied in spring can be connected to the force, which is not conducive to the early growth of spring shoots.
Autumn basal fertilization program for apples
The target yield per mu is more than 5,000 catties
Plan 1: 5 bags of Yijiabao + 3 bags of slow-release formula fertilizer or 3 bags of Crop Jiale 18-18-18 light carbon compound fertilizer + 2 bags of silicon, calcium, magnesium and potassium fertilizer + 2 kg deep three feet of easy to apply.
Plan 2: 5 bags of billions of bacteria + 2 bags of fruit and grain balance fertilizer + 1 bag of Mengli calcium.
Plan 3: 7 bags of full-nutrient no-mix fast fruit fertilizer.
The target yield per mu is less than 5,000 catties
Plan 1: 4 bags of bio-organic fertilizer + 3 bags of ecological long-term fertilizer or 3 bags of crop 15-15-15 light carbon compound fertilizer + 2 bags of silicon-calcium-magnesium-potassium fertilizer + 1 kg deep and three feet deep and easy to apply.
Plan 2: 3 bags of Mengding bottom fertilizer + 2 bags of fruit grain balance fertilizer + 1 bag of Mengli calcium.
Plan 3: 6 bags of full-nutrient no-mix fast fruit fertilizer.
Author: He Jucai, lecturer of Zhongnong Le Fruit Science Research Institute
Source: Zhongnongle