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The effect of DCD on nitrogen losses from sheep urine patches applied to lysimeters in autumn

Moir, James L.
Wild, M. A.
Cameron, Keith C.
Di, Hong J.
Conference Contribution - published
Fields of Research
The intensification of modern pastoral agriculture has increased the risk of environmental degradation. The use of nitrification inhibitor technology has been shown to reduce nitrate (NO₃ ⁻) leaching losses and nitrous oxide (N₂O) emissions from New Zealand dairy pasture systems. However, published data on inhibitor usage to reduce these losses from intensive sheep winter grazing systems is also needed. A trial was conducted at Lincoln University using lysimeters in a Templeton silt loam soil. Four treatments (control, control + DCD, urine, urine + DCD) were applied in May 2009, with urine applied in patches at an N loading rate of 300 kg/ha with dicyandiamide (DCD) at 10 kg/ ha. Water (simulating rainfall) was applied in spring to supplement natural rainfall. Nitrous oxide gas sampling and leachate collections were made for 4 months. Application of DCD reduced the N₂O emissions by up to 72% (4.55 kg N₂O-N/ha without DCD to 1.32 kg N₂O-N/ha with DCD) from late autumn applied sheep urine and also reduced the amount of NO₃ ⁻-N leached by up to 70% (147 kg NO₃ ⁻-N/ha to 44 kg NO₃ ⁻-N/ ha). These results indicate that the use of DCD may be a useful technology to mitigate N losses from sheep break-fed pasture over winter. The need for further research in this area is discussed.
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Copyright © The Authors and New Zealand Grassland Association.
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