Effects of tillage, nitrogen placement, and wheel compaction on denitrification rates in the corn cycle of a corn-oats rotation
1994
Hilton, B.R. | Fixen, P.E. | Woodard, H.J.
Denitrification rates under various tillage systems were determined in the corn (Zea mays L.) cycle of a corn-oats (Avena sativa L.) rotation. Denitrification was measured directly with an in-situ soil cover method which supplied the soil with acetylene (C2H2) and evacuated the nitrous oxide (N2O) produced. Denitrification rates were measured in both a field or non-wheel track (NWT) area and in a compacted wheel track (WT) area for the no-till (NT), chisel plow (CH), moldboard plow (MP) tillage systems after nitrogen (N) was applied by broadcast/incorporation with 112 kg N/ha as ammonium nitrate. Nitrogen was also applied to the NT treatment by injection with modified anhydrous ammonia knives prior to planting. Most of the cumulative N loss occurred over a 22 day period following heavy rainfall in June. Denitrification was greatest on days after rainfall events for the NT systems. Cumulative N loss was estimated at 25, 16, and 11 kg N/ha from May 29-September 8 for NT, CH, and MP treatments, respectively, for the broadcast/incorporated N application. Mean denitrification rates from WT areas were about 1.6 times greater than the NWT areas.
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