Nitrous oxide and methane fluxes from organic soils under agriculture

• Published in: European journal of soil science Vol. 49; no. 2; pp. 327 - 335
• Main Authors: FLESSA, H, WILD, U, KLEMISCH, M, PFADENHAUER, J
• Format: Journal Article
• Language: English
• Published: Oxford BSL Blackwell Science Ltd 01-06-1998; Blackwell Science
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Fundamental and applied biological sciences. Psychology; Organic matter; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Soil science; Europe; Germany; Bavaria; Methane; Nitrogen fertilization; Cultivated field; Climate; Gas emission; Cultivated soil; Organic soil; Environmental factor; Temperate zone; Field experiment; Seasonal variation; Greenhouse gas; Soil science; Grassland soil; Cultural practice; Annual variation; Permanent grassland; Soil management; Agroecosystem; Carbon cycle; Measurement in situ; Edaphic factor; Biogeochemistry; Nitrogen cycle; Mass flow rate; Peat soil; Agrometeorology; Air ground interface; Gas exchange; Nitrogen protoxide
• ISSN: 1351-0754; 1365-2389
• DOI: 10.1046/j.1365-2389.1998.00156.x

Trace gas fluxes of N2O and CH4 were measured weekly over 12 months on cultivated peaty soils in southern Germany using a closed chamber technique. The aim was to quantify the effects of management intensity and of soil and climatic factors on the seasonal variation and the total annual exchange rates of these gases between the soil and the atmosphere. The four experimental sites had been drained for many decades and used as meadows (fertilized and unfertilized) and arable land (fertilized and unfertilized), respectively. Total annual N2O‐N losses amounted to 4.2, 15.6, 19.8 and 56.4 kg ha–1 year–1 for the fertilized meadow, the fertilized field, the unfertilized meadow and the unfertilized field, respectively. Emission of N2O occurred mainly in the winter when the groundwater level was high. At all sites maximum emission rates were induced by frost. The largest annual N2O emission by far occurred from the unfertilized field where the soil pH was low (4.0). At this site 71% of the seasonal variation of N2O emission rates could be explained by changes in the groundwater level and soil nitrate content. A significant relationship between N2O emission rates and these factors was also obtained for the other sites, which had a soil pH between 5.1 and 5.8, though the relation was weak (R2 = 15–27%). All sites were net sinks for atmospheric methane. Up to 78% of the seasonal variation in CH4 flux rates could be explained by changes in the groundwater level. The total annual CH4‐C uptake was significantly affected by agricultural land use with greater CH4 consumption occurring on the meadows (1043 and 833 g ha–1) and less on the cultivated fields (209 and 213 g ha–1).