1. Extraroot fertilization: The most commonly used methods in production are spreading or spraying branches, injecting branches and spraying leaves.
The application or spraying of branches is suitable for supplementing trace elements such as iron and zinc in apple trees, and white paint can be applied with the trunk in winter. The method is to add ferrous sulfate or zinc sulfate to the white lime slurry, and its concentration can be higher than that of foliar spraying. Bark can absorb nutrients, but the efficiency is not high; After the rain, the fertilizer on the trunk gradually seeps into the bark, or rushes into the soil under the crown, and then is absorbed by the root system. Branches can be injected with high-pressure sprayers and improved syringes. First drill a hole in the trunk, and then inject it into the trunk with a syringe. It is used for injection of ferrous sulfate (1% ~ 4%) and chelated iron (0.05% ~ 0. 10%) to prevent iron deficiency, and boric acid and zinc sulfate are also added. Any element deficiency is related to soil conditions, and trunk injection is effective when fertilization by soil is not effective.
2. Irrigation and fertilization:
Irrigation fertilization means that fertilizer can be used through irrigation system (sprinkler irrigation, micro-irrigation and drip irrigation), and the dosage and time can be arranged reasonably and flexibly according to the needs of trees. As for what kind of fertilizer, you can apply compound fertilizer or micro-fertilizer. There are many varieties on the market.