O11-01 : Nitrous oxide (N2O) reducing denitrifiers inoculated to soil have mitigated N2O emission and promoted red clover growth
1Grad. Sch. Agri. Life Sci., Univ. of Tokyo, 2Ibaraki Univ. College of Agri., 3ROM Co., Ltd
In Japan, soils are main source of N2O emissions, and contribute 25% of the total anthropogenic N2O sources, mainly due to nitrogen (N) fertilizer use. Moreover, the excessive use of chemical fertilizers in agriculture has various adverse effects on soil quality, soil ecological services, and thus crop productivity. Therefore, development of environmentally-friendly bio-fertilizers has been attempted worldwide. The aim of this study is to achieve effective strains for development of the bio-fertilizers. Seven N2O-reducing denitrifier strains (Azospirillum sp. and Herbaspirillum sp.), previously isolated from rice paddy soils, were inoculated into soil after application of chemical fertilizer in greenhouse. The red clover (Trifolium pretense L.) germination rate was significantly higher after inoculation of the N2O-reducing denitrifier strains. The fresh weight, seedling height and leaf area were greater in soils inoculated with the N2O-reducing denitrifier strains than non-inoculated soils. Moreover, the N2O emission was mitigated after inoculation of the N2O-reducing denitrifier strains in comparison with non-inoculated treatments. In conclusion, the N2O-reducing denitrifiers could promote red clover germination rate and growth, and mitigate N2O emission from soils as well. It will be practical to develop the bio-fertilizer by using these N2O-reducing denitrifiers.
keywords:Bio-fertilizer,denitrification,greenhouse gas,plant growth promotion rhizobacteria,soil fertility