Manganese concentrations and pH in a small, tea field river catchment were measured in 1998 and 2015. The pH levels dropped between May and June of 1998, but in 2015 there were few changes throughout the year. This difference is hypothesized to have been due to reduced fertilizer use between April and July and improved fertilization methods. While manganese concentrations were consistently lower in 2015, further investigations of manganese loading are required. Furthermore, a comparison of field soil and forest soil indicates that one factor leading to high manganese concentrations observed in a small river was a corresponding high concentration in tea field soils; additional factors include significant water-soluble components, exchangeable ions, and the exposure of carbonates, which are soluble in weak acids.
