Nitrogen efflux in a small forested catchment during rain event studies on nutrient effluents from a small forested catchment, 2
1995
Ikuta, K. (Tottori Univ. (Japan). Faculty of Agriculture) | Fujiyama, H. | Nagai, T.
Processes of nitrogen efflux from a small forested catchment, during 2 rain events on July 9 in 1991 and June 22 in 1993, we studied in Hirusen Experimental Forest of Tottori University, Okayama prefecture, Japan. The distribution of soil nitrogen in the catchment was observed in 1991. The conceptual model, a tank model based on a cascade of reservoirs, was developed to separate surface runoff, throughflow and base flow from stream discharge during these rain events. The peak nitrogen concentration during the rain event on July 9 in 1991 (R=77mm) was 1.27 mg L(-1), however in the case of June 22 in 1003 (R=44mm) it was 2.84 mg L(-1). Soil nitrogen content in the surface layer was high in the upper soil. On an average gradient slope, more nitrogen accumulated in the lower part of the slope (upper, 287.6; middle, 445.9; foot, 653.1 g m(-2), respectively). The amount of nitrogen leached by the extraction experiment from litter, black volcanic ash soil and lower volcanic ash soil were 368.0, 26.0 and 9.0 mg kg(-1), respectively. During these rain events, on July 9 in 1991 and June 22 in 1993, the results of multiple regression analysis suggested that the throughflow component (Q2 and Q3) increased nitrogen efflux. It was suggested that the pathway of throughflow might be located in the nitrogen-rich upper soil layers. Therefore, the throughflow component may efflux more nitrogen than other components
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