2019 Fiscal Year Final Research Report

Development of evaluating methods for soil nitrogen-fixing activity and its activation by bamboo power and microbial fertilizers

Research Project

PDF

Project/Area Number	17K07709
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Applied microbiology
Research Institution	Utsunomiya University
Principal Investigator	Maeda Isamu 宇都宮大学, 農学部, 教授 (10252701)
Co-Investigator(Kenkyū-buntansha)	平井英明宇都宮大学, 農学部, 教授 (20208804)
Project Period (FY)	2017-04-01 – 2020-03-31
Keywords	非共生型窒素固定 / 竹粉 / 牛糞堆肥 / ニトロゲナーゼ / メタゲノム
Outline of Final Research Achievements	This study has been performed to contribute to reducing the dependence of ammonia in chemical fertilizers by increasing the nitrogen-fixing activity in rice-paddy fields. Bamboo powder as a carbon source and cow dung compost as a nitrogen source were supplied to the soil. Soil nitrogen-fixing bacterial counts and activities were low before irrigation, highest during paddy cultivation, and decreased again after rice harvest. The higher activity was observed in soil fertilized with cattle manure compared to chemical fertilizer. After harvest, the activity increased in the soil fertilized with cow dung compost by adding bamboo powder. Changes in soil bacterial communities were also analyzed. The influence on the bacterial community was the largest in seasonal variation from pre-irrigation to the rice cultivation periods, followed by the difference between soils fertilized with chemical fertilizer and cow dung compost and the difference whether or not bamboo powder was applied.
Free Research Field	応用微生物学
Academic Significance and Societal Importance of the Research Achievements	研究により水稲栽培において，7月のイネ栽培期に灌水前あるいは収穫後と比べ窒素固定細菌数が多く，かつ高いニトロゲナーゼ活性となり，灌水前から栽培期にかけて細菌叢の変化も最も顕著であることが示された．潅水，気温上昇，イネの栽培による環境条件の変化が土壌細菌の活性や菌叢に対する影響が非常に大きいことが明らかとなった．また，施用する資材は細菌叢やニトロゲナーゼ活性に変化をもたらすが，化学肥料と牛糞堆肥の違いが最も影響が大きく，竹粉施用の有無は牛糞堆肥との組み合わせで副次的な影響が認められることが明らかとなり，牛糞堆肥や竹粉の施用が水田のアンモニア生産能向上に寄与する可能性が示された．