Stabilization of soil organic matter-Pursuit of its process and substances

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02862
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38010:Plant nutrition and soil science-related
• Research Institution: Nagoya University
• Principal Investigator: Watanabe Akira 名古屋大学, 生命農学研究科, 教授 (50231098)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 土壌化学 / 土壌有機物 / 炭素蓄積 / 腐植物質

Outline of Final Research Achievements

To clarify the stabilization process of and nature of soil organic carbon (SOC), the relationship between the chemical structure of humic substances and their degradability, the nature of bound-type humin, the formation process of microbe derived bound-type SOC, and the relationship between the chemical structure of applied organic matter (AOM) and the accumulation form of SOC. The results revealed that humic substances with higher blackness and aromaticity are more resistant to microbial degradation under conditions without physical or chemical protection, that bound-type humin is not humic/fulvic acids that cannot be extracted by strong adsorption to minerals, that microbe derived organic matter, in particular saccharides forms new bound-type SOC, and that bound-type SOC can be produced from both AOM components and microorganisms which utilized AOM, but which one accumulates more depends on the chemical structure of the AOM.

Free Research Field

土壌圏物質循環学

Academic Significance and Societal Importance of the Research Achievements

土壌への炭素蓄積量を増大させるあるいは安定的に維持することは、持続的生物生産と地球温暖化対策の両面においてきわめて重要である。そこで、土壌有機物の安定化過程とその実体について研究し、これまで不明であった化学構造に基づく微生物分解性の違い、鉱物への吸着によって安定化している腐植物質の特徴、菌体を経由した結合型土壌有機物の生成過程を明らかにし、また、施用する有機物の種類（構造）によって土壌有機炭素の生成過程と蓄積形態が異なることを示した。