GROUNDWATER CHEMISTRY NEAR A TEA PLANTATION IN THE CENTER OF SHIZUOKA PREFECTURE, JAPAN

Abstract

To investigate the relation between fertilizer and groundwater quality, the well water chemistry near tea plantations was studied. Well waters were classified by the difference of pH value into 3 types. A type is acidic, B type is acidic to neutral and C type is neutral. Average concentrations of NO3-N and HCO3- were: A type, 33.8mg/L and 0.1mg/L, B type, 13.1mg/L and 8.2mg/L; C type, 6.9mg/L and 60.0mg/L, respectively. The decrease in pH values was associated with the increase in the concentration of NO3-N. The concentration of carbonate increased with pH value. Therefore, the decrease of amount of nitrogen fertilization used in tea plantations and the sufficient carbonate were thought to induce rising the pH value. As concentrations of metal in well water increased with decrease in pH value, metal concentrations and pH values were influenced by the use of fertilizer and carbonate.