What type of fertilizer is best for fruit tree fertilization?

Fertilizers should be applied in a balanced combination of four types. Fruit trees require a scientific mix of four fertilizer categories: organic fertilizers, macronutrient fertilizers (nitrogen, phosphorus, potassium), bio-fertilizers, and secondary and micronutrient fertilizers. Organic fertilizer serves as the foundation, improving soil quality and enhancing fruit quality; therefore, autumn base fertilization should primarily use organic fertilizers supplemented with chemical fertilizers. Nitrogen, phosphorus, and potassium are the main components, with varying ratios depending on the fruit tree—approximately 1:0.6:1 for apples and about 1:1.41:1.25 for grapes. Secondary and micronutrients must not be overlooked, as deficiencies in boron, zinc, iron, and others can directly cause nutrient deficiency disorders, affecting yield.

Fertilization should combine base and top-dressing. Base fertilizer is best applied in late September to the end of October during autumn, when root growth is at its peak and nutrient uptake efficiency is highest. Top-dressing should be adjusted flexibly according to growth stages: before spring shoot cessation, apply mainly nitrogen and potassium fertilizers; during fruit enlargement, focus on potassium fertilizer supplemented with a small amount of nitrogen.
Fertilization methods should be scientific. Replace broadcasting with band application or radial trench application, applying fertilizer in trenches near the tree drip line at a depth of 40–50 cm. Where possible, integrate water and fertilizer management to apply small amounts frequently, adjusting fertilizer according to irrigation.