Tuesday, November 6, 2007
231-23
Nitrous oxide/ Nitrogen ratio in Iowa soils in dependence on soil factors.
Marek Jarecki, USDA-ARS National Soil Tilth Laboratory, AgCert National Soil Tilth Lab., 2150 Pammel Drive, Ames, IA 50011-4429, Timothy Parkin, National Soil Tilth Lab,USDA-ARS, Ames, IA 50011, Alvarus Chan, Consultant, AgCert International, PO Box 116, Melbourne, FL 32902, Jerry Hatfield, National Soil Tilth Laboratory, USDA-ARS, 2110 University Blvd., Ames, IA 50011, and Raymond Jones, AgCert Canada, 1008 11th St Se, High River, AB T1V 1L3, Canada.
In the laboratory experiment several intact soil cores were used to examine N2O/N2 ratios from denitrification upon different soil factors. Incubation of soil cores without C2H2 additions were performed to measure total N2O production. To inhibit nitrification the acetylene series was introduced at C2H2 partial pressure of 0.01 kPa. Total denitrification emission N-gas (N2 + N2O) was measured in the same cores in the presence of 10 kPa C2H2. In the investigated soils the N2O production from denitrification was higher than from nitrification. Nitrous oxide from denitrification was 55-61% of total N2O production in two clay loam soils, and 67% of total N2O production on a sandy loam soil. The ratio of N2O from denitrification to total denitrification gases (N2+N2O) ranged from 0.40 to 0.51 in the clay soils and was 0.37 in the sandy loam soil.