| Project/Area Number |
20K05770
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 38010:Plant nutrition and soil science-related
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| Research Institution | Tottori University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
遠藤 常嘉 鳥取大学, 農学部, 教授 (70423259)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2020: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | 乾燥地 / 灌漑農地 / 低温 / 塩の溶解度 / 土壌ソーダ質化 / 塩類土壌 / リン / 溶脱 / ソーダ質土壌 / 灌漑 / Na塩溶解度の温度依存性 / リン溶脱 |
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| Outline of Research at the Start |
乾燥地の灌漑農地の土壌塩類化による劣化機構について，これまでほとんど考慮されてこなかった「温度条件（灌漑水温，地温）」に着目して検討する．
すなわち，冬季寒冷な大陸性気候下の乾燥地の灌漑農地を想定し，春先の低温期に慣行的に行われる冷たい水による灌漑（冷水灌漑）が土壌塩類の溶解特性・動態にどのように影響するのか，また，それが土壌塩類化の促進要因（とくに深刻な状況を生み出す土壌ソーダ質化の助長要因）になるのかを追究する．
さらに，冷水灌漑による土壌塩類組成変化が土壌養分動態に及ぼす影響として，溶解特性が塩組成に影響されやすいリンに焦点を当て，冷水灌漑が農地からのリン溶脱に及ぼす影響を検討する．
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| Outline of Final Research Achievements |
The results of this study showed that the de-salinization process associated with cold water irrigation in dryland irrigated croplands promotes soil sodication process. This is due to the leaching inhibition of Na-carbonate, whose solubility decreases at low temperatures, and its residual in the soil. The results also suggest that the Na-Ca exchange reaction at low temperatures promotes the adsorption of Na ions on the soil. The quality and quantity of clay minerals in the soil were also significant factors in sodication process. Furthermore, soil sodication increased the solubility of soil inorganic phosphorus and the risk of leaching from agricultural lands.
Irrigation water in drylands contains bicarbonate ions, so irrigation with cold water during low-temperature periods poses a universal risk of soil degradation due to soil sodication and environmental impacts due to phosphorus leaching from agricultural land.
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| Academic Significance and Societal Importance of the Research Achievements |
塩類動態について温度環境に着目しておこなった本研究で明確にできた乾燥地の灌漑農地における冷たい水による灌漑管理の負の側面，すなわちソーダ質化による土壌劣化とリン溶脱の問題は，大陸性気候下の乾燥地における冬季灌漑などの慣行的な灌漑管理を見直し，灌漑農業の持続性と環境の保全を高める対策に繋がる基礎的な知見になると期待できる．また，冷涼な雨季を持つ乾燥地の土壌生成，とくにソロネッツの生成に関する基礎的知見としての意味ももつ．
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