Detailed Explanation of Key Techniques for Soil Testing and Formula Fertilization of Chinese Cabbage

1. Fertilizer Requirements:

Chinese cabbage has a long growth period, high yield, and an extremely large nutrient demand, with the highest uptake of potassium, followed by nitrogen, calcium, phosphorus, and magnesium. The overall fertilizer requirement pattern is: nutrient uptake is relatively low at the seedling stage, increases markedly at the rosette stage, and is highest at the heading stage. Adequate nitrogen nutrition is of particularly great significance for promoting the formation of large green leaves and improving photosynthetic efficiency. If phosphorus and potassium supply is insufficient in the later stage, head formation is often difficult.

2. Fertilization Techniques:

At a medium fertility level, the fertilizer application rate per mu throughout the entire growth period is 2000-2500 kg of farmyard manure (or 300-350 kg of commercial organic fertilizer), 13-16 kg of nitrogen fertilizer, 5-8 kg of phosphorus fertilizer, and 10-12 kg of potassium fertilizer. Nitrogen and potassium fertilizers are divided into a base fertilizer application and two topdressing applications, while phosphorus fertilizer is applied entirely as base fertilizer. Chemical fertilizers and farmyard manure (or commercial organic fertilizer) are applied together.

Base fertilizer: Apply 2000-2500 kg of farmyard manure or 300-350 kg of commercial organic fertilizer per mu, 4-5 kg of urea, 11-17 kg of diammonium phosphate, 6-7 kg of potassium sulfate, and 20 kg of calcium nitrate.

Topdressing: At the rosette stage, apply 10-12 kg of urea and 7-9 kg of potassium sulfate per mu; at the early heading stage, apply 10-12 kg of urea and 7-9 kg of potassium sulfate per mu.

Foliar topdressing: Spraying a 0.3% calcium chloride solution or a 0.25%-0.50% calcium nitrate solution during the growth period can reduce the incidence of tipburn. Spraying a 0.5%-1.0% urea solution or a 0.2% potassium dihydrogen phosphate solution at the early heading stage can improve the commercial value of Chinese cabbage.

Bao Jinshan