Nitrification and Denitrification in Conventional and No-Tillage Soils1
- Peter M. Groffman2
Nitrification and denitrification were studied over the course of a year in conventional and no-tillage agroecosystems. Soils were sampled monthly at three depths (0–5 cm, 5–13 cm, 13–21 cm). Nitrification was quantified by measuring nitrite (NO−2-N) production from soils amended with ammonium (NH+4-N) and chlorate. Denitrification was quantified by measuring nitrous oxide production, in the presence of acetylene, from unaltered soil cores and from soils amended with nitrate (NO−3-N) glucose and chloramphenicol. Nitrification and denitrification exhibited marked pulses of activity in response to residue input in both conventional and no-tillage systems. Nitrification and denitrification activities were consistently higher in the top 5 cm of no-tillage soils than in conventional tillage soil and a reverse pattern was observed at lower depths. Total amounts of nitrification and dentrification activity over 0 to 21 cm were not significantly different between treatments on an annual basis.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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