Methane oxidation by soils of an N limited and N fertilized spruce forest in the Black Forest, Germany

• Published in: Soil biology & biochemistry 2001-02, Vol.33 (2), p.145-153
• Main Authors: Steinkamp, R, Butterbach-Bahl, K, Papen, H
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Forest soils; Fundamental and applied biological sciences. Psychology; Germany; Methane oxidation; NH 4+ inhibition of CH 4 oxidation; Organic matter; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Seasonal variations; Soil science; Soil temperature
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/S0038-0717(00)00124-3

A long-term experiment was performed at two sites in the Black Forest (Germany), in which methane oxidation rates of soils of an unfertilized spruce site and of a spruce site that had been fertilized with 150 kg of N ha −1 (as (NH 4) 2SO 4) were followed seasonally over approximately three years (1994–1996). Throughout the observation period, the soil at both sites functioned exclusively as a sink for atmospheric CH 4. Mean CH 4 oxidation rates at both sites were almost identical in magnitude (82.2±34.6 μg CH 4 m −2 h −1 for the unfertilized site, and 84.2±31.8 μg CH 4 m −2 h −1 for the N fertilized site) during the observation period. Results from an additional small-scale N fertilization experiment indicate that high N applications to the soil of this N-limited forest resulted only in a small reduction of CH 4 oxidation: less than 30% for less than 72 d. The results indicate that the atmospheric CH 4 uptake activity of the soils of forest ecosystems characterized by N limitation has the capacity to recover rapidly from the inhibitory effects of high inorganic N inputs. CH 4 oxidation rates at both sites showed no significant diurnal variation. However, there were significant seasonal differences in the magnitude of CH 4 oxidation rates at both experimental sites with high rates during summer, relative low rates during winter and intermediate rates during spring and autumn. Correlation analysis revealed that CH 4 oxidation rates were positively correlated with soil temperature and negatively with soil moisture. However, at low soil temperatures (