| Denitrification and nitrous oxide production was examined in three cropping systems: barley (Hordeum vulgare L.), soybean (Glycine max L.), and corn (Zea mays L.). Different sampling positions in proximity to a plant (row, inter-row, quarter-row) did not result in significant differences in denitrification or nitrous oxide production. However, cores taken at the 12.5-17.5 cm depth were significantly higher than cores taken at the 2.5-7.5 or 22.5-27.5 cm depths in the corn field. This pattern was not observed in the barley and soybean fields. Seasonal changes were observed in the regulators of denitrification and nitrous oxide production and were different for each crop. Denitrification and nitrous oxide production exhibited seasonal patterns with major episodes in the spring and minor episodes in the fall. When light fraction organic matter was examined as a source of available carbon for denitrification, nitrous oxide, or carbon dioxide production, no significant correlations were observed. |
