Consequences of nitrogen fertilization on soil methane consumption in a productive temperate deciduous forest

• Published in: Biology and fertility of soils 2005-04, Vol.41 (3), p.182-189
• Main Authors: Chan, A.S.K, Steudler, P.A, Bowden, R.D, Gulledge, J, Cavanaugh, C.M
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Deciduous forests; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Growing season; kinetics; methane; mineralization; nitrification; nitrogen fertilizers; Nitrogen, phosphorus, potassium fertilizations; organic horizons; Soil amendment; soil amendments; Soil columns; Soil depth; soil nutrient dynamics; Soil profiles; Soil science; soil temperature; soil water content; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Temperate forests
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/s00374-004-0822-7

To investigate the consequences of long-term N additions on soil CH^sub 4^ dynamics, we measured in situ CH^sub 4^ uptake rates, soil profiles and kinetics parameters during the growing season in a temperate deciduous forest in northwestern Pennsylvania (Allegheny College Bousson Environmental Forest). Measurements were made in control and adjacent plots amended with 100 kg N ha^sup -1^ year^sup -1^ for 8 years. We found that the in situ consumption rates were 0.19±0.02 (mean±SE) for the control and 0.12±0.01 mg CH^sub 4^-C m^sup -2^ h^sup -1^ for the N treatment, indicating that consumption had been reduced by 35% after 8 years of N amendments. Despite the large difference in rates of consumption, there were no differences in the CH^sub 4^ concentration profiles between the control and N-amended plots. Laboratory incubations of CH^sub 4^ consumption throughout the soil column (organic horizon and mineral soil depths) showed that rates were greatest in the organic horizon of both control and N-amended soils, although consumption was reduced by 42% in the N-amended plot. However, the rate in the organic horizon was only about 50% the rate measured in organic horizons at other temperate forests. The apparent K^sub m^ [K^sub m(app)^] value in the organic horizon of the control plot was fourfold less than the K^sub m(app)^ value in the organic horizon of another temperate forest, but similar to the K^sub m(app)^ values in adjacent plots amended with N for a decade. Unlike results for other temperate forests, K^sub m(app)^ values at Bousson generally did not decrease with soil depth. These results indicate that N cycling strongly controls the CH^sub 4^-consuming community, and suggest that alterations of the N cycle due to N deposition or addition may alter rates and the location of CH^sub 4^ consumption by soils, even in soils with high N content and cycling rates.[PUBLICATION ABSTRACT]