Seasonal and Annual Fluxes of Inorganic Constituents in a Small Catchment of a Japanese Cedar Forest near the Sea of Japan

Abstract

Fluxes of major ions in rainfall (RF), throughfall plus stemflow (TF + SF), and stream water (SW) were measured for five water years in a small catchment of a Japanese cedar forest near the Sea of Japan. The fluxes of most ions in RF and in TF + SF, including the non-sea-salt constituents, increased from late autumn to midwinter owing to the seasonal westerly wind. The concentrations of most ions in SW showed no obvious seasonal trend during the study period, whereas NO À 3 concentrations were lowest in summer, with a small seasonality. The Ca 2+ and Mg 2+ outputs in SW were approximately 3.7 and 1.8 times the TF + SF inputs of these cations, respectively. The large net outputs of base cations in the catchment may indicate a decrease in the soil's acid-neutralizing capacity. Annual dissolved inorganic nitrogen inputs in RF and in TF + SF were 17.7 and 17.9 kg N ha −1 year −1 , respectively, which exceeded previously published thresholds in Europe and the U.S. (i.e., the values at which these inputs increased NO À 3 levels in SW) and equaled the highest level of nitrogen deposition previously reported in Japan. The NO À 3 concentrations in SW were relatively high even in summer. During high-precipitation events, NO À 3 concentrations in SW increased with increasing water discharge, and the pH decreased simultaneously during several events. Nitrogen deposition may contribute to the high NO À 3 concentrations in SW and the temporary acidification that occurred during the rain events.

Export flux of unprocessed atmospheric nitrate from temperate forested catchments: A possible new index for nitrogen saturation

“…The catchment is characterized by a high loading rate of atmospheric nitrogen, as well as nitrate enrichment of more than 50 µmol L -1 in the stream water eluted from the catchment. Kamisako et al (2008) proposed that atmospheric nitrogen inputs are exceeding the biological demand at this site.…”

“…Details of the Kajikawa experimental forest have been described in past studies (Kamisako et al, 2008;Sase et al, 2012;Sase et al, 2008). Lake Ijira (Fig.…”

“…1(b)) was 5 used to determine the areal deposition flux of NO 3 − atm (Kamisako et al, 2008;Sase et al, 2008). Using the sampler, bulk depositions were collected into sample bottles at intervals of about four weeks.…”

Influence of land use changes on water chemistry in streams in the State of São Paulo, southeast Brazil

“…Several studies reported the impact of land use effect on streams, both in temperate and tropical watersheds (Kamisako et al 2008, Rai et al 2010, Andrade et al 2011. Streams located in undisturbed sites were reported to be more affected by soil characteristics and precipitation, although the streams located in disturbed areas were affected by different sources according to the land use. )…”

“…The effects of change in land use on the biogeochemistry have also been described in the literature for both major rivers and streams. It has been shown that these changes affect nitrate, ammonium, calcium, potassium and aluminum concentrations in streams located in temperate (Wang et al 2006, Kamisako et al 2008, Rai et al 2010) and tropical regions (Neill et al 2006, Andrade et al 2011.…”