Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10846169 | Soil Biology and Biochemistry | 2005 | 5 Pages |
Abstract
The effects of animal treading on denitrification in a mixed ryegrass-clover pasture were studied. A single treading event of moderate or severe intensity was applied in plots during spring by using dairy cows at varying stocking rates (4.5 cows 100Â mâ2 for 1.5 or 2.5Â h, respectively). Treading caused a significant short-term 21 days) increase in denitrification. Denitrification rates reached a maximum of 52Â g N2O-NÂ haâ1Â dayâ1 at 8 days after severe treading compared to 2.3Â g N2O-NÂ haâ1Â dayâ1 under nil treading. Thereafter, denitrification rates declined, and were similar to non-trodden control plots after 28 days. Soil aeration, was significantly reduced by treading as expressed by water-filled porosity. In addition, soil NH4+-N and NO3â-N concentrations were also increased by treading. We propose that the underlying processes involved in increasing denitrification under treading were two-fold. Firstly, treading caused a temporary (e.g. 3 days after treading) reduction in soil aeration through soil physical damage, and secondly, reduced soil N utilisation prompted by reduced plant growth led to increased soil NH4+-N and NO3â-N availability. This study shows that treading, without the influence of other grazing animal factors (e.g. excretion), can cause a large short-term stimulation of denitrification in grass-clover pastures.
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Authors
John C. Menneer, Stewart Ledgard, Chris McLay, Warwick Silvester,