METHOD OF RAPIDLY MEASURING EXCHANGEABLE CALCIUM AMOUNT OF SOIL BY USING SPECTROPHOTOMETER

摘要

PURPOSE: A method of rapidly measuring exchangeable calcium amount of soil is provided to reduce time and cost, while preventing environmental contamination by reducing amount of reagents used. CONSTITUTION: A method comprises a first step of precipitating soil by using sodium chloride solution; a second step of adding sodium hydroxide, formaldehyde and sodium tetraphenyl borate to the solution; and a third step of defining the amount of soil exchangeable calcium by measuring optical density of the sample by using a spectrophotometer. The formaldehyde, used as a liquid reagent, is added 2 to 10 drops, wherein 1 drop is 0.02mL. The sodium tetraphenyl borate, used as a powder reagent, is added by 1 spoon which is capable of measuring 0.01 to 0.5g. The exchangeable calcium is measured by the spectrophotometer at 500 to 720nm.