Key Points of Post-Harvest Cultivation and Management Techniques for Citrus Orchards

During the annual growth cycle, mature citrus trees go through flower bud differentiation, flowering, fruit set, physiological fruit drop, fruit expansion, three flushes of new shoots and branch growth, and three root growth peaks, consuming a large amount of energy and nutrients, severely weakening tree vigor. In addition, various pest and disease residues concentrate within them, bringing many adverse effects to the following year's growth and fruiting of citrus trees. Therefore, strengthening post-harvest cultivation and management of citrus orchards to rapidly restore tree vigor is of vital significance to the following year's citrus production. The author believes that post-harvest cultivation and management of citrus orchards should focus on implementing the following technical measures:

Timely foliar fertilizer application. After harvest, timely application of foliar fertilizer is a reform in the application method of traditional post-harvest fertilizer. Compared with rhizosphere fertilization, it has the characteristics of quick application, reduced waste, lower cost, and fast results. This can not only quickly supplement tree nutrients, prevent leaf drop, and rapidly restore tree vigor, but also effectively promote flower bud differentiation and enhance the tree's cold resistance. At present, there are many varieties of foliar fertilizers suitable for post-harvest application, but compound and organic foliar fertilizers have the best effect. Special attention should be paid to controlling the concentration of the foliar spray solution at about 0.2%, not exceeding 0.3%, and it should be applied promptly after harvest.

Apply wintering fertilizer as early as possible. Wintering is the nutrient foundation for spring growth of citrus, so this fertilization is also called "base fertilizer" in citrus production. The application rate should depend on tree vigor, applying 70-100 kg of organic-inorganic compound fertilizer per mu, and it should be completed before mid-November as much as possible. Citrus growers with the means can broadcast the fertilizer over the entire orchard and then plow the whole orchard. Growers with limited labor can dig ring-shaped trenches beneath the tree canopy drip line and bury the fertilizer.

Carry out winter orchard cleaning properly. Winter orchard cleaning is the most effective way to reduce the overwintering base of pests and diseases and control harmful organism populations. Winter orchard cleaning includes three tasks: picking up and deeply burying fallen fruit in the orchard, pruning diseased and pest-infested dead branches and carrying them out of the orchard for centralized burning, and spraying the tree canopy with orchard-cleaning agents. Picking up and deeply burying (about 1 m deep) fallen fruit in the orchard is an important measure that cannot be ignored for controlling harmful organism populations that damage citrus fruit, and this work should be carried out promptly after harvest is completed. After pruning diseased and pest-infested dead branches, immediately spray the tree canopy with lime sulfur mixture or sodium abietate-type agents.