Nitrous oxide emissions from animal urine as affected by season and a nitrification inhibitor dicyandiamide

Abstract

Purpose Nitrous oxide emissions from pasture soils account for one third of total agricultural greenhouse gas emissions in New Zealand. The aim of this study was to determine nitrous oxide (N 2 O) emissions from animal urine patches under summer (with irrigation) and winter conditions as affected by dicyandiamide (DCD) in grazed grassland in New Zealand. Materials and methods Sixteen monolith lysimeters were collected from an established perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) pasture on a Templeton fine sandy loam (Udic Ustochrept) located near Lincoln University on the Canterbury plains of New Zealand to study the N 2 O emissions from animal urine as affected by season and a nitrification inhibitor dicyandiamide. The experiment was conducted in the summer of 2008-2009 and the winter of 2009 with four treatments (control, control+DCD (10 kg ha −1 ), urine (1,000 kg N ha −1 ), urine+DCD) for both seasons. N 2 O fluxes from the pasture were measured in summer and winter. Results and discussionResults showed that the application of urine significantly increased N 2 O emissions and the application of nitrification inhibitor, DCD, to pasture soil was very effective in reducing N 2 O emissions both in summer and winter. Total N emissions from urine-N applied at 1,000 kg N ha −1 were 7.8 kg N 2 O-N ha −1 in the summer season and this was much lower than the 12.7 kg N 2 O-N ha −1 emitted during the winter season. The application of DCD reduced summer N 2 O-N emissions to 4.8 kg N 2 O-N ha −1 and winter N 2 O-N emissions to 3.9 kg N 2 O-N ha −1 , representing 40% and 69% reductions in the summer and winter seasons, respectively. Conclusions The results demonstrate that N 2 O emissions from animal urine-N in grazed pastures were much higher in the winter season than in the summer season with irrigation and that DCD was more effective in reducing N 2 O emissions in the high-emitting winter season.

An assessment of nitrification inhibitors to reduce nitrous oxide emissions from UK agriculture

“…This is in contrast to the findings of Weiske et al ( The mean N 2 O EF for urine applications from the present study was 0.41%, within the range of 0.02-1% reported by Yamulki et al (1998) from measurements on the heaviertextured North Wyke soil, but considerably lower than the IPCC default EF of 2% for cattle excreta, suggesting that the UK should develop country-specific EF for cattle urine and dung for use in the UK greenhouse gas inventory in a similar way to New Zealand which derived values of 1 and 0.25% for cattle urine and dung, respectively (Luo et al 2009). Qiu et al (2010) reported higher EF for winter than summer urine applications (1.27 and 0.78%, respectively) in a study in New Zealand. In the UK, winter grazing generally does not occur so a representative EF should integrate spring, summer and autumn conditions.…”

“…A more conservative emission reduction factor of 50% was suggested for inclusion in the New Zealand agricultural emission inventory to reflect adoption of this mitigation measure (Clough et al 2007). Qiu et al (2010) showed DCD to be more effective at reducing emissions from urine applications to grassland in New Zealand in the higher-emitting winter season (mean 69% reduction) than in summer (mean 40% reduction). It is known that the microbial degradation of DCD in soil is temperature dependent (Kelliher et al 2008) and maximum nitrification inhibition has been reported to occur at soil temperatures ⩽10°C (Di andCameron 2004, Smith et al 1989).…”

Livestock production in a changing climate: adaptation and mitigation research in Australia

“…As the annual N fertiliser rate is the key input into national inventory Tier 1 and Tier 2 methods (DCCEE 2010a), offset methods that result in net reductions in annual fertiliser rate would be reasonably simple to implement. Likewise, nitrification inhibitors, used as a coating on fertiliser or as a spray, have been well documented for temperate latitudes in Australia (Kelly et al 2008) and New Zealand (Di et al 2009Qiu et al 2010;de Klein et al 2011).…”

Nitrous oxide emissions from pastures during wet and cold seasons

“…; Qiu et al . ). High N 2 O emissions from winter‐grazed pastures are often observed when the soil moisture is near or above field capacity, which is indicative of reduced soil aeration promoting denitrification or nitrifier‐denitrification activity (Balaine et al .…”

“…However, in grazed pastures, higher N 2 O emissions may actually occur during the autumn/winter seasons, compared to the emissions in spring/summer seasons (Klein et al 2003;Saggar et al 2004a;de Klein et al 2006;Luo et al 2007;Qiu et al 2010). High N 2 O emissions from winter-grazed pastures are often observed when the soil moisture is near or above field capacity, which is indicative of reduced soil aeration promoting denitrification or nitrifier-denitrification activity Zhu et al 2013).…”