Phytotron studies to compare nitrogen losses from corn-planted soil by the 15-N balance or direct dinitrogen and nitrous oxide measurements
1988
Heinemeyer, O. (Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (Germany, F.R.). Inst. fuer Pflanzenernaehrung und Bodenkunde) | Haider, K. | Mosier, A.
Containers filled with soil mixed with potassium nitrate highly enriched in 15-N were planted with corn (Zea mays L.) and kept in a phytotron under controlled conditions for 79 days. Soil water content was normally maintained at exactly 60 % water- holding capacity (-33 kPa), but it was increased several times to 85 % (-5 kPa) for short periods to favour denitrification. The soil headspace was sealed from the phytotron atmosphere and aerated by a continuous stream of air. Nitrous oxide emission was measured by estimating the N2O concentration differences in the air entering and leaving the containers. Emission of N2 was estimated by mass spectrometry from changes in the N2-composition in the temporarily enclosed soil headspace. Both methods were carefully checked for accuracy by different tests. At specific times during the experiment the distribution of 15-N between plants and soil was determined and a 15-N balance established. Possible reasons for these differences are discussed.
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