Effects of type and amount of applied nitrogen fertilizer on nitrous oxide fluxes from intensively managed grassland
✍ Scribed by G. L. Velthof; O. Oenema; R. Postma; M. L. Van Beusichem
- Publisher
- Springer Netherlands
- Year
- 1996
- Tongue
- English
- Weight
- 886 KB
- Volume
- 46
- Category
- Article
- ISSN
- 1385-1314
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✦ Synopsis
Five field experiments and one greenhouse experiment were carried out to assess the effects of nitrogen (N) fertilizer type and the amount of applied N fertilizer on nitrous oxide (N20) emission from grassland. During cold and dry conditions in early spring, emission of N20 from both ammonium (NH:) and nitrate (NO,) containing fertilizers applied to a clay soil were relatively small, i.e. less than 0.1% of the N applied. Emission of N20 and total denitrification losses from NO, containing fertilizers were large after application to a poorly drained sand soil during a wet spring. A total of 5-12% and 8-14% of the applied N was lost as N20 and via denitrification, respectively. Emissions of N20 and total denitrification losses from NH, + fertilizers and cattle slurry were less than 2% of the N applied. Addition of the nitrification inhibitor dicyandiamide (DCD) reduced N20 fluxes from ammonium sulphate (AS). However, the effect of DCD to reduce total N20 emission from AS was much smaller than the effect of using NH: fertilizer instead of NO, fertilizer, during wet conditions. The greenhouse study showed that a high groundwater level favors production of N20 from NO, fertilizers but not from NH: fertilizers. Increasing calcium ammonium nitrate (CAN) application increased the emitted N20 on grassland from 0.6% of the fertilizer application rate for a dressing of 50 kg N ha-' to 3.1% for a dressing of 300 kg N ha-'. In another experiment% N20 emission increased proportionally with increasing N rate. The results indicate that there is scope for reducing N20 emission from grasslands by choosing the N fertilizer type depending on the soil moisture status. Avoiding excessive N application rates may also minimize N20 emission from intensively managed grasslands.