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Reducing gaseous losses of nitrogen from cattle slurry applied to grassland by the use of additives
Author(s) -
Pain Brian F,
Thompson Rodney B,
Rees Yvonne J,
Skinner Jonathon H
Publication year - 1990
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740500202
Subject(s) - denitrification , slurry , loam , nitrification , volatilisation , ammonium , ammonia volatilization from urea , chemistry , nitrogen , ammonia , agronomy , environmental chemistry , environmental science , soil water , zoology , environmental engineering , soil science , biology , organic chemistry
Losses of nitrogen (N) through ammonia (NH 3 ) volatilisation and denitrification were determined following the application of cattle slurry to grassland in autumn or spring. Denitrification was examined on two contrasting soils. A system of small wind tunnels was used to measure NH 3 loss and an acetylene inhibition technique for denitrification. Between 31 and 84% of the ammonium N (NH 4 + ‐N) applied in slurry was lost through NH 3 volatilisation. Acidifying the slurry to pH c 5.5 prior to application reduced these losses to between 14 and 57%. On a freely drained loam soil, denitrification from unacidified slurry applied in the autumn at 80 m 3 ha −1 was continuous throughout the winter, with the maximum rate of 0.91 kg N ha −1 day −1 occurring a few weeks after slurry application. The total denitrification losses were equivalent to about 29% of the NH 4 + ‐N applied for this treatment and 41% for the acidified slurry. The nitrification inhibitor dicyandiamide reduced the amount of N lost through denitrification by 70% when applied with the slurry at 25 kg ha −1 , by 55% at 20 kg ha −1 and by 30% at 15 kg ha −1 . The nitrification inhibitor nitrapyrin did not appreciably reduce denitrification. Denitrification losses were consistently small from slurry applied to the freely drained loam soil in spring, or to a poorly drained, silty clay in autumn or spring. Neither nitrification inhibitor was of benefit in these situations.