飽和バッファーの代替堰設定下での性能:設計および管理への影響
Gabriel M Johnson1, Thomas M Isenhart1, Christopher Hay2,3
1Department of Natural Resource Ecology and Management, Iowa State University, Ames, Iowa, USA.
Journal of environmental quality
|January 21, 2026
まとめ
飽和バッファーの季節的な管理は、タイル排水からの硝酸窒素(NO3-N)の効果的な除去を実現します。しかし、長期間の完全排水期間は、かなりのNO3-N損失につながる可能性があり、慎重な現場の検討が必要です。
科学分野:
- 農業水管理; 環境科学; 土壌科学
背景:
- 飽和バッファーは、サブサーフェス排水からの硝酸窒素(NO3-N)の流出を軽減するための重要なエッジ・オブ・フィールド(圃場端)の実践です。; 季節的な堰標高管理が飽和バッファーにおけるNO3-N除去効率に及ぼす影響は、十分に研究されていません。
研究 の 目的:
- 制御ボックスの堰標高管理が飽和バッファーにおけるNO3-N除去に及ぼす影響を評価すること。; USDA NRCS保全実践基準604からの設計予測と比較して、現場での処理性能を評価すること。
主な方法:
- 2022年から2024年まで、253 mの飽和バッファー(約6ヘクタール)の流量とNO3-N負荷量を監視しました。; 堰標高を「完全排水」、「生育期」、「休閑期」の設定に調整しました。; さまざまな管理期間中の処理効率と流量バイパスを分析しました。
主要な成果:
- 29日間の「完全排水」期間中、流量の25%とNO3-N負荷量の28%がバッファーを迂回しました。; NO3-N除去効率は、2023年および2024年と比較して2022年の方が高かったです。; 実際の処理流量は予測を超えましたが、ピーク排水流量は低く、設計以上の処理能力利用率を示しました。
結論:
- 季節的な堰管理により、飽和バッファーでかなりのNO3-N除去を達成できます。; 長期間の「完全排水」期間では、かなりのNO3-N損失を防ぐために慎重な管理が必要です。; 観測された性能と予測された性能との間の不一致は、飽和バッファーの設計方法論の改訂が必要であることを示唆しています。
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