Cultivation management for retaining grain production in polluted farmland by controlling the mobility of heavy metals in soil

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H00961
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 41:Agricultural economics and rural sociology, agricultural engineering, and related fields
• Research Institution: Osaka Metropolitan University (2022); Osaka Prefecture University (2019-2021)
• Principal Investigator: Horino Haruhiko 大阪公立大学, 大学院農学研究科, 教授 (30212202)
• Co-Investigator(Kenkyū-buntansha): 中村 公人 京都大学, 農学研究科, 教授 (30293921) ; 櫻井 伸治 大阪公立大学, 大学院農学研究科, 講師 (30531032) ; 中桐 貴生 大阪公立大学, 大学院農学研究科, 准教授 (80301430)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 重金属 / 土壌汚染 / 化学形態 / 移行 / 不動化 / 有機物 / 腐熟度

Outline of Final Research Achievements

The immobilization of metals in soils using organic soil amendments (OA), which aims at suppressing uptake of toxic metals to crops has been gaining prominence as an alternative to conventional engineering and biological remediation techniques for heavy metal contamination in farmlands. Previous studies have shown that cow manure compost has a high immobilization effect, that humification of OA increases this effect. We examined the contribution of humification of OA to the immobilization effect of heavy metals and conducted plant pot experiments using soybeans (Glycine max) and rice (Oryza sativa) to show guidelines for safe agricultural production. The results from our study showed the relationship between the immobilization effect of OA and C/N ratio, which is an index of humification. Furthermore, plant pot tests suggested that the possibility of transfer to edible parts was low, and that cow manure inhibited transfer to crops.

Free Research Field

灌漑排水学

Academic Significance and Societal Importance of the Research Achievements

重金属汚染農地においてたとえ短期的であっても安全な農作物を生育させることは，特に途上国においてはフードセキュリティを担保することだけでなく，本質的な環境修復に対応する時間を確保する点からも重要である．結果的に，どのような有機物を用いるべきかについての指標を見出すことができ，有機物の取捨選択の時間を短縮させることで現場圃場への迅速な対応を見込めることが期待されるが，土壌管理によっては有機物を投入することで重金属が可溶化する場合や，必ずしも重金属の化学形態（可給性）と作物への移行量とが応答しない場合もあり，これらの対処にはさらなる検討が望まれる．