| 摘要 |
PROBLEM TO BE SOLVED: To provide a fertilizer that secures elution of water soluble phosphate, while restraining elution of water soluble cadmium.SOLUTION: Water soluble cadmium, which is sometimes contained in a fertilizer itself, is eluted from superphosphate of lime in contact with water. Elution of water soluble phosphate is secured by use of hydroxyapatite and pH control, while elution of water soluble cadmium is restrained, in a fertilizer containing water soluble phosphate and water soluble cadmium. The solid fertilizer containing water soluble phosphate and water soluble cadmium is blended with hydroxyapatite and as necessary an alkali, to be in the range of pH 4-6 when dissolved in water. The water soluble phosphate is eluted, while the water soluble cadmium is adsorbed by the hydroxyapatite, in the range of pH 4-6. Elution of the water soluble phosphate is thus secured, while elution of the water soluble cadmium is restrained, when the fertilizer is applied to cultivation soil and cultivation water. |
