Key Technical Points for Fertilizer and Water Management in Red Fuji Apple Orchards
How should fertilizer and water be managed for Red Fuji apples? Please advise. For Red Fuji orchards, basal fertilizer is generally best applied in late September, mainly using farmyard manure. For young orchards with a yield below 2000 kg per mu, apply 2-3 kg of fertilizer per kg of fruit; for high-yielding orchards with a yield of 2000-3000 kg per mu, apply 1 kg of fertilizer per kg of fruit; for high-yielding orchards above 3000 kg per mu...
How should fertilizer and water be managed for Red Fuji apples? Please advise.
For Red Fuji orchards, basal fertilizer is generally best applied in late September, mainly using farmyard manure. For young orchards with a yield below 2000 kg per mu, apply 2-3 kg of fertilizer per kg of fruit; for high-yielding orchards with a yield of 2000-3000 kg per mu, apply 1 kg of fertilizer per kg of fruit; for high-yielding orchards above 3000 kg per mu, apply 1.5 kg of fertilizer per kg of fruit. When fertilizing, the pre-fruiting fertilizer ratio for young trees is N:P:K = 2:1:0; during the fruiting period, the ratio is N:P:K = 2:2:1.5; during full bearing period, N:P:K = 2:2:4; after 15-16 years, the ratio is adjusted to N:P:K = 2:2:1. As for application methods, young trees can be fertilized by hole application or trench application, while mature trees can be fertilized by trench application or broadcast application throughout the orchard. When fertilizing, care must be taken to mix the fertilizer thoroughly with the soil, and apply it within the main root distribution layer (about 40 cm). For newly planted young orchards, start fertilizing from the second year. Combined with basal fertilizer application, deep plowing of the orchard can be carried out once, using tree-disk deep plowing, with the tree disk expanded year by year for deep plowing, and whole-orchard deep plowing, with a depth of 40-60 cm being suitable. For topdressing, applying fertilizer to vigorous young trees during the spring shoot growth cessation period and autumn shoot growth cessation period can achieve the purpose of supplying nutrients for medium and short shoot bud differentiation and accumulating stored nutrients. This prevents excessive vegetative growth, promotes differentiation, reduces consumption, and increases accumulation. For bearing trees, the first topdressing in March before bud break (applying 0.5 kg urea per tree) with a large amount of nitrogen fertilizer and an appropriate amount of potassium fertilizer can promote flowering and pollination, improve fruit set rate, and also promote spring shoot growth, fruit enlargement, and flower bud differentiation, improving yield and quality. The second topdressing in mid-June with an appropriate amount of nitrogen fertilizer and more phosphorus fertilizer can promote fruit set, and also prompt spring shoots to stop growth in time, which is beneficial for flower formation and fruit development.
For foliar spraying, it can begin about 10 days after flowering, spraying once every 10 days with a mixture of urea and monopotassium phosphate (half of each), spraying 3-4 times consecutively, which can promote early leaf emergence (referring to leaves below flowers and short shoot leaves), expand and thicken leaf surface. Spraying phosphorus fertilizer 4 times consecutively within one and a half months before harvest can promote fruit coloring, improve flavor, and enhance quality. After harvest, spraying nitrogen fertilizer and phosphorus-potassium fertilizer twice consecutively has a notable effect on preventing leaf senescence, improving leaf function and bud strengthening for organic nutrient production and storage, and reducing premature leaf drop. The most suitable temperature for foliar spraying is 18°C-25°C. In summer, it is best to spray before 11 AM or after 3 PM to avoid high temperatures causing phytotoxicity. Foliar spraying should be done carefully and thoroughly, spraying both the upper and lower surfaces of leaves evenly, with the lower surface absorbing more quickly. To improve nutrient absorption rate, an adhesive agent such as neutral detergent powder can be added to the nutrient solution. If rain occurs after spraying, it will seriously affect the results, and timely re-spraying should be done. According to measurements, if heavy rain occurs 8 hours after spraying, it can wash away 80%-90% of the urea remaining on the leaf surface, and 40%-60% from the lower leaf surface.
II. Water Management
The water requirements of fruit trees can be divided into three stages throughout the year: March to mid-May is the first stage, late May to early August is the second stage, and after mid-August is the third stage. Before spring bud break (March), applying an appropriate amount of irrigation combined with topdressing is beneficial for stabilizing and raising soil temperature, promoting shoot and leaf growth, flowering, fruit set, and fruit development. This can achieve the purpose of relatively controlling vegetative growth, promoting flower bud differentiation, and improving fruit quality. Before the freeze-up in November, a winter watering can be done.
For dryland orchards without irrigation conditions, the winter slack season can be used to transport water for watering trees. Currently adopted technical measures such as orchard film mulching, grass planting, straw mulching, hole-stored fertilizer water with plastic film covering, and use of soil water-retaining agents are economical and practical for regulating water use, with remarkable results.
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