How to fertilize large cherries for high yields? Mastering the nutrient requirements is key

    In recent years, the planting area of large cherries with good economic returns has gradually expanded. During cultivation, how can fertilization ensure good quality and high yields of large cherries?

Cherry topdressing

    I. Fertilization periods for cherries:Cherries have a short growth period and require rapid, concentrated fertilization. Bud break, leaf expansion, flowering, and fruit development through maturity are concentrated from April to June, and after harvest, flower bud differentiation is also concentrated within a relatively short period, so the tree's nutritional status before overwintering directly affects its growth and development. Therefore, applying base fertilizer in autumn and topdressing during the flowering and fruiting period and after cherry harvest are essential. Base fertilizer applied in early autumn is generally done in August and September, exerting its fertilizer effect in the same year, increasing nutrient accumulation, and favoring flowering and fruiting.

    According to the nutrient requirements of cherries, topdressing can be divided into 3 applications: first, pre-flowering fertilizer, mainly nitrogen and phosphorus fertilizer, to promptly supplement nutrients and promote flower bud sprouting and spring shoot growth; second, fruit-swelling fertilizer, mainly nitrogen and potassium fertilizer, with phosphorus fertilizer added, to promote cherry enlargement, reduce physiological fruit drop, improve fruit quality, and supplement the tree's nutrients; third, topdressing before cherry coloring, mainly quick-acting potassium fertilizer, applied 20-25 days before harvest; fourth, supplementary fertilizer after fruit harvest, mainly quick-acting fertilizer, preferably compound fertilizer. 

    II. Fertilization rates for cherries

    1. Nutrient requirements: Cherries have a high demand for nitrogen and potassium, in similar amounts, and a low demand for phosphorus. The suitable ratio of nitrogen, phosphorus, and potassium is 10:1.5-10:12. In addition, the demand ratio of calcium, magnesium, and sulfur for cherries is 1.4-2.4:0.3-0.8:0.2-0.4. These elements play an important role in improving cherry quality, especially calcium, which can prevent fruit cracking in large cherries, increase cherry firmness, extend the supply period, reduce physiological disorders during storage, increase the stress resistance of the cherries and the tree, and reduce frost damage during the flowering period.

    2. Nutrient content required by cherry fruit: According to research measurements, for every 100 kg of cherries produced, about 1.04 kg of pure nitrogen, 0.14 kg of pure phosphorus, and 1.37 kg of pure potassium need to be absorbed. Adding the needs for root, branch, and leaf growth, rainwater leaching, and soil fixation, a cherry orchard with medium soil fertility should apply fertilizer annually at 2-3 times the cherry yield.

    3. Nutrient content in leaves of normal cherry trees: In normal cherry trees, the main elements in leaf dry matter are: nitrogen 2.33-3.27%, phosphorus 0.23-0.32%, potassium 1.25-1.92%, calcium 1.62-2.60%, magnesium 0.49-0.74%. Micronutrient contents are: sulfur 124-150 mg per kg, iron 119-203 mg per kg, manganese 44-60 mg per kg, boron 38-54 mg per kg, zinc 20-50 mg per kg, copper 8-28 mg per kg, molybdenum 0.5-1 mg per kg. Through diagnostic analysis, if levels are below the above contents, fertilizer should be supplemented promptly to avoid deficiency symptoms. The suitable application rate of various fertilizers should be determined according to the yield level of the specific cherry orchard. Fertilizing with a formula of nitrogen, phosphorus, and potassium will significantly promote high and stable yields of cherries.

    4. Amount of organic fertilizer applied as base fertilizer: Organic fertilizer can improve the soil, increase soil fertility, reduce environmental pollution, improve cherry quality, and enhance cherry color, brightness, firmness, and sugar content. For high-yield cherries, apply 150-200 kg of fermented pig or chicken manure organic fertilizer per tree as base fertilizer.

    5. Spraying micronutrient fertilizer: Supplement according to deficiency, appropriately adding boron, zinc, magnesium, and other elements. Spraying a 0.3% borax solution at the flowering stage can promote flower organ development and increase the fruit-setting rate. After fruit set, spraying a 0.3% potassium dihydrogen phosphate solution has a clear effect on increasing cherry sugar content and coloring.

    III. Cherry fertilization methods

    According to the nutrient requirements of cherries and the characteristics of the fertilizer, the base fertilizer should be applied by the surface-spreading method. First make a bed around the tree disk, spread the organic fertilizer on the surface of the tree disk, and water immediately, with 100 kg of water per tree.

Advantages of surface-spreading base fertilizer: first, a large absorption area and high utilization rate; second, nutrients are not easily lost, giving good results; third, the soil remains loose and does not become compacted. For foliar topdressing, the leaf spray method is generally used so that nutrients are directly absorbed by the leaves, making it efficient and rapid. It mainly uses urea and potassium dihydrogen phosphate, with urea concentration at 0.3-0.5% and potassium dihydrogen phosphate concentration at 0.3%. Spraying should be done from top to bottom, covering both the underside and upper surface, with the standard being that no liquid drips from the leaves and fruit.

    Note: Cherry is a chlorine-sensitive tree species, so potassium fertilizer must be potassium sulfate, not potassium chloride.