title: N2O production pathways in the subtropical acid forest soils in China.
abstract: To date, N(2)O production pathways are poorly understood in the humid subtropical and tropical forest soils. A (15)N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N(2)O production in four subtropical acid forest soils (pH<4.5) in China. The results showed that denitrification was the main source of N(2)O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N(2)O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N(2)O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N(2)O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N(2)O product ratios from nitrification. The ratio of N(2)O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Zhang
authors.forename: Zucong
authors.initials: Z
authors.lastname: Cai
authors.forename: Tongbin
authors.initials: T
authors.lastname: Zhu
mesh_terms: D002681:China; D006863:Hydrogen-Ion Concentration; D058458:Nitrogen Cycle; D009585:Nitrogen Dioxide / Q000032:analysis / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D014197:Trees
chemical_list: D012987:Soil; D012989:Soil Pollutants; D009585:Nitrogen Dioxide