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Evaluating impact of land use and N budgets on stream water quality in Hokkaido, Japan

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タイトル: Evaluating impact of land use and N budgets on stream water quality in Hokkaido, Japan
著者: Woli, Krishna Prasad 著作を一覧する
Nagumo, Toshiyuki 著作を一覧する
Hatano, Ryusuke 著作を一覧する
キーワード: impact factor
livestock density
N budget
point source pollution
water quality
発行日: 2002年 7月
出版者: Kluwer Academic Publishers
誌名: Nutrient Cycling in Agroecosystems
巻: 63
号: 2-3
開始ページ: 175
終了ページ: 184
出版社 DOI: 10.1023/A:1021146707412
抄録: This study was conducted to evaluate the impact of land use system and N loadings to the environment estimated from N budgets on quality of stream water in Hokkaido, Japan. A case study was carried out in three towns of southern Hokkaido, which are Shiraoi, Yakumo, and Shizunai, characterized by intensive poultry farming (IPF), dairy cattle farming (DCF), and race horse farming (RHF), respectively. The estimation of N budgets using an N flow model indicated that the highest disposal N (880 Mg N yr-1) was generated in the IPF town and it resulted in 250 kg ha-1yr-1 surplus N in croplands. The disposal N was much lower in the DCF and the RHF town (102 and 71 Mg N yr-1, respectively) than that of the IPF town. Cropland surplus N in DCF town was 31 kg N ha-1yr-1, whereas RHF town had negative N balance. The linear regression analysis indicated that NO3-N concentration in stream water was significantly correlated with the proportion of upland field in drainage basins. The regression slopes varied among the towns, and it was the highest for IPF (0.040), intermediate for DCF (0.023) and the lowest for RHF town (0.006). The multiple regression analysis showed that regression slopes were significantly correlated (R2 = 0.77 at 5% level) with livestock disposal N and cropland surplus N. Therefore, we assumed that these regression lines were the baselines for non-point source pollution, and the regression slopes were determined to act as impact factors of stream water quality. However, two sampling sites in the IPF area were scattered above the baseline. This fact strongly suggests that the area was affected by point source pollution.
資料タイプ: article (author version)
出現コレクション:雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

提供者: Krishna Prasad Woli


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