1a. Objectives (from AD-416):
Quantify and assess the management-related effect on greenhouse gas emissions from peat soils.
1b. Approach (from AD-416):
Measurements will be conducted at typical fen forage production sites (plus reference site) representing a ground water table gradient: a. intensively managed grassland (2-3 cuts followed by 1-2 grazing cycles) N fertilization: approximately 200 kg/ha/year, groundwater table during the growing season greater than 60 cm below soil surface b. extensively managed grassland (pasture), no additional N fertilization, groundwater table 30–50 cm below soil surface c. reference site: restored fen, no agricultural management, groundwater table 0 – 30 cm below soil surface d. ploughing up grassland (intensively managed) to maize (“worst case scenario”) At each site, gas fluxes of CO2, N2O, and CH4 as well as nitrate leaching will be measured. The quantification of leaching N-losses will be done by suckling cups. Emission of greenhouse gases will be measured by the ‘Eddy-Covariance, EC’ (CO2) and the ‘Closed Chamber, CC’ (N2O, CH4) method. In 2011, installation of a first EC-tower at one of the fen sites (i.e. intensively managed grassland) will be implemented to acquaint local scientists with installation, operation, and data management of EC systems. After the first successful implementation, two additional EC towers will be deployed at two of the remaining experimental fen sites in 2012. Year-round measurements lasting for at least 2 years will be collected from all three sites.
3. Progress Report:
Continued to monitor carbon dioxide flux from three grasslands in northern Germany with the following characteristics: 1) an un-grazed, unfertilized site on a peat soil; 2) a grazed high-fertility site on peat soil; and 3) a grazed high-fertility site on mineral soil. Fluxes from the three grasslands will be monitored until June 2014 when net carbon dioxide gain or loss over a two-year period will be calculated.