Key techniques of soil testing and formula fertilization for Chinese cabbage

1. Characteristics of fertilizer requirement:

Chinese cabbage has a long growth period, high yield, great demand for nutrients and the largest absorption of potassium, followed by nitrogen, calcium, phosphorus and magnesium. The general characteristics of fertilizer requirement were as follows: the absorption of nutrients was less in the seedling stage, increased significantly in the rosette stage, and the highest in the pericardium stage. Adequate nitrogen nutrition is of great significance to promote the formation of hypertrophic green leaves and improve photosynthetic efficiency. If the supply of phosphorus and potassium is insufficient in the later stage, it is often not easy to form balls.

2. Fertilization technology:

Under the medium fertility level, the amount of fertilizer applied per mu during the whole growth period is 2000ml 2500kg of farm manure (or 300mu of commercial organic fertilizer), 16kg of nitrogen fertilizer, 8kg of phosphate fertilizer and 1012kg of potash fertilizer. Nitrogen and potash fertilizer are divided into base fertilizer and secondary topdressing, all phosphate fertilizer is used as base fertilizer, chemical fertilizer and farm fertilizer (or commercial organic fertilizer) are mixed.

Base fertilizer: 2000MUE 2500kg per mu or 300MUE 350kg of commercial organic fertilizer, 5kg of urea, 11kg of diammonium phosphate, 7kg of potassium sulfate and 20kg of calcium nitrate.

Topdressing: in rosette stage, urea 10MU 12kg, K2SO4 7MUE 9kg; Urea 10MU 12kg, K2SO4 7MUE 9kg at the initial stage of Baoxin.

Extra-root topdressing: spraying 0.3% calcium chloride solution or 0.25% Mel 0.50% calcium nitrate solution during the growing period can reduce the incidence of dry heartburn. Spraying 0.5% Mel 1.0% urea or 0.2% potassium dihydrogen phosphate solution at the initial stage of heading can increase the commercial value of Chinese cabbage.

Bao Jinshan