Spring, Pond and River Water Chemistries Derived From a Tea Plantation in Central Shizuoka Prefecture

Abstract

To investigate the influence of chemical fertilizers on groundwater and surface water neighboring tea plantations in central Shizuoka prefecture, a time series of chemical compositions and nitrogen isotopic ratios within local wells, springs, rivers and ponds were studied. The pH of spring and pond water in some areas maintained basic acidity with neither any noticeable changes in nitrogen isotopic ratios nor any disappearance of nitrate within the ponds and low concentrations of chlorophyll and phosphorus. Therefore, the activities of photosynthesis in the ponds of this area were very low due to low concentrations of phosphorus. However, the pH of spring water in the other areas maintained basic neutrality to alkali with high concentrations of Ca2+ and SO42" and low concentrations of NO,-because of soil and fertilizer improvement. Concentrations of Al, Co, Ni, Zn and Mn ions in the groundwater and surface water increased with the decrease of pH values. Then, soil and fertilizer improvement is important.

The impacts of the water quality of the inflow water from tea fields on irrigation reservoir ecosystems

“…He suggested that the long term and great application of ammonium sulfate created acidic reservoirs. After that several studies were carried out for low pH and high NO 3 -N concentrations in Shizuoka, which the authors refer to in this paper (Ii et al 2000;Tanaka T. et al 2002). However, these studies drew conclusions from a small amount of data although the survey term was long.…”