Bulletin of the Faculty of Agriculture, Shimane University

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Bulletin of the Faculty of Agriculture, Shimane University 25
1991-12-21 発行

農業集水域からの汚濁物質流出特性(I) : 水質変動と流出負荷量

Pollution Loading Outflows from an Agricultural Basin(I) : Characteristics of Concentrations and Loadings
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Description
Water qualities and discharge were monitored regularly in the agricultural basin during two irrigation periods and one non-irrigation period. The rate of paddy field in the basin changed within two irrigation periods, I.e. 36% (1988) and 45% (1989) due to conversion to upland field. The loadings were calculated onlyin the dry-weather days,bocause there was a little problem in measuing the discharge.
At the lowest end of the basin, the average concentrations of T-N, T-P and T-COD during the irrigation periods were 2.13mg/1 (1988) 1.68mg/1 (1989), 0.171mg/1 (1988) 0.399mg/1 (1989), and 2.5mg/1 (1988) 4.5mg/1 (1989) respectively. The tendency was found that the pollution loading outflows were higher than the inflow by irrgation. Furthermore [0utflow loading]-[Inflow loading]during the irrigation period in 1989 were higher than 1988. This may be caused by the large amounts of loading from the paddy fields in the basin.