Influence of digestate quality on N2O production mechanism in the soil using isotopic N2O analyzer

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K00594
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental engineering and reduction of environmental burden
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Riya Shohei 東京農工大学, 工学(系)研究科(研究院), 准教授 (80725606)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 亜酸化窒素 / 発酵残渣 / 炭化物 / 安定同位体 / SP

Outline of Final Research Achievements

We evaluated N2O reduction and its mechanism in the soil amended with digestate biochar. Biochar produced at higher temperature showed higher N2O mitigation than those at lower ones for both flooded and non-flooded soil. SP value analysis suggested that N2O was produced by nitrification in the oxic condition and denitrification in the anoxic condition. Therefore, biochar addition would mitigate these reactions in the soil.
Furthermore, we evaluated how soluble matter in the biochar affect N2O mitigation. Biochar extract addition showed reduction of N2O emission. By comparing with results of biochar added soil, contribution of soluble matter in biochar to N2O mitigation was higher for biochar produced at higher temperature. These results suggest control of soluble matter would be important in the biochar production for N2O mitigation.

Free Research Field

環境工学

Academic Significance and Societal Importance of the Research Achievements

本研究ではN2Oアナライザ―により土壌から発生する亜酸化窒素の生成機構を明らかにしたとともに、発酵残渣の炭化物が土壌から発生する亜酸化窒素（N2O）を削減する作用があることを明らかにした。炭化物のN2O削減機構に関しては炭化物そのものの作用が研究されていたが、本研究では炭化物の溶存成分がN2Oの削減にどう影響するかを調査した。その結果、調製温度が高い炭化物ほど溶存成分がN2O削減に寄与することが示唆された。この成果は、炭化物を調製する際に、溶存成分を制御することも重要であることを示している。