Study on the technical index system of soil testing fertilization for leafy vegetables in Guangdong: potassium

Fertilization experiments were conducted to select the flowering Chinese cabbage and the pakchoi cabbage as the representative leafy vegetables in vegetable fields of variety fertility levels in Guangdong province.The data of the soil available potassium content,the total doses of potassium and the relative yield of leafy vegetables were statistical analyzed.The proper mathematical models based on regression equations,and the abundant or deficient index by recommended about the soil available potassium content and the total doses of potassium for leafy vegetables in Guangdong were obtained.Results showed: The regression equation index for soil available potassium content was y=14.977ln(x)+24.987,the correlation coefficient was 0.788.And the regression equation of the total doses of potassium,for the flowering Chinese cabbage was y=-3.5253ln(x) + 24.354,the correlation coefficient was 0.677;for the pakchoi cabbage,the index was y=-1.2576ln(x)+11.465,the related coefficient was 0.700.The soil available potassium content was 5 mg/kg、5～28 mg/kg、28～107 mg/kg and107 mg/kg,while the dimensions of the relative product was 50%、50%～75%、75%～95% and 95%,according to the mathematical model.The proposed index of supplying potassium for the flowering Chinese cabbage and the pakchoi cabbage was respectively 9.4 kg and 9.2 kg per 667 m2,when the soil available potassium content was 5 mg/kg.The index was respectively 7.5～9.4 kg and 6.9～9.2 kg per 667 m2,when the contents was 5～28 mg/kg.The index was respectively 6.0～7.5 kg and 5.1～6.9 kg per 667 m2,when the content was 28～107 mg/kg.The total doses of potassium should be less than 6.0 kg per 667 m2 for the Flowering Chinese cabbage and 5.0 kg per 667 m2 for the pakchoi cabbage,when the soil available potassium content was 107mg/kg.