Interannual variation in nitrous oxide emissions from perennial ryegrass/white clover grassland used for dairy production

Burchill, W.E.; Li, Dejun; Lanigan, Gary; Williams, M.; Humphreys, J.

doi:10.1111/gcb.12595

Cited by 43 publications

(31 citation statements)

References 46 publications

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“…Interannual variability of N 2 O emissions as reported by many studies (Burchill et al ., ; Oates et al ., ), and the representativeness of the study period, limit the generalization of these results. The study period had a wet early summer (Fig.…”

Section: Discussionmentioning

confidence: 97%

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

et al. 2016

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Future liquid fuel demand from renewable sources may, in part, be met by converting the seasonally wet portions of the landscape currently managed for soil and water conservation to perennial energy crops. However, this shift may increase nitrous oxide (N 2 O) emissions, thus limiting the carbon (C) benefits of energy crops. Particularly high emissions may occur during the transition period when the soil is disturbed, plants are establishing, and nitrate and water accumulation may favor emissions. We measured N 2 O emissions and associated environmental drivers during the transition of perennial grassland in a Conservation Reserve Program (CRP) to switchgrass (Panicum virgatum L.) and Miscanthus x giganteus in the bottom 3-ha of a watershed in the Ridge and Valley ecoregion of the northeastern United States. Replicated treatments of CRP (unconverted), unfertilized switchgrass (switchgrass), nitrogen (N) fertilized switchgrass (switchgrass-N), and Miscanthus were randomized in four blocks. Each plot was divided into shoulder, backslope, and footslope positions based on the slope and moisture gradient. Soil N 2 O flux, soil moisture, and soil mineral nitrogen availability were monitored during the growing season of 2013, the year after the land conversion. Growing season N 2 O flux showed a significant vegetation-bylandscape position interaction (P < 0.009). Switchgrass-N and Miscanthus treatments had 3 and 6-times higher cumulative flux respectively than the CRP in the footslope, but at other landscape positions fluxes were similar among land uses. A peak N 2 O emission event, contributing 26% of the cumulative flux, occurred after a 10.8-cm of rain during early June. Prolonged subsoil saturation coinciding with high mineral N concentration fueled N 2 O emission hot spots in the footslopes under energy crops. Our results suggest that mitigating N 2 O emissions during the transition of CRP to energy crops would mostly require a site-specific management of the footslopes.

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Section: Discussionmentioning

confidence: 97%

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

et al. 2016

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“…For 2 consecutive years, they obtained annual emissions of 0.55 and 0.44 g N m −2 , respectively, bracketing the result for the IFR site. Burchill et al (2014) found, for a rotationally grazed and intensively fertilised ryegrass pasture in Ireland, annual N 2 O emissions over 4 years to range from 0.44 to 3.44 g N m −2 . The annual emissions from the IFR site are within this range, near the lower end.…”

Section: N 2 O Emissions and Nitrogen Inputsmentioning

confidence: 97%

“…The annual emissions from the IFR site are within this range, near the lower end. Burchill et al (2014) also measured the annual emissions from ungrazed, unfertilised ryegrass pasture. These ranged from 0.17 to 0.63 g N m −2 , i.e.…”

Section: N 2 O Emissions and Nitrogen Inputsmentioning

confidence: 99%

Combining two complementary micrometeorological methods to measure CH<sub>4</sub> and N<sub>2</sub>O fluxes over pasture

et al. 2016

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Abstract. New Zealand's largest industrial sector is pastoral agriculture, giving rise to a large fraction of the country's emissions of methane (CH 4 ) and nitrous oxide (N 2 O). We designed a system to continuously measure CH 4 and N 2 O fluxes at the field scale on two adjacent pastures that differed with respect to management. At the core of this system was a closed-cell Fourier transform infrared (FTIR) spectrometer, which measured the mole fractions of CH 4 , N 2 O and carbon dioxide (CO 2 ) at two heights at each site. In parallel, CO 2 fluxes were measured using eddy-covariance instrumentation. We applied two different micrometeorological ratio methods to infer the CH 4 and N 2 O fluxes from their respective mole fractions and the CO 2 fluxes. The first is a variant of the flux-gradient method, where it is assumed that the turbulent diffusivities of CH 4 and N 2 O equal that of CO 2 . This method was reliable when the CO 2 molefraction difference between heights was at least 4 times greater than the FTIR's resolution of differences. For the second method, the temporal increases of mole fractions in the stable nocturnal boundary layer, which are correlated for concurrently emitted gases, are used to infer the unknown fluxes of CH 4 and N 2 O from the known flux of CO 2 . This method was sensitive to "contamination" from trace gas sources other than the pasture of interest and therefore required careful filtering. With both methods combined, estimates of mean daily CH 4 and N 2 O fluxes were obtained for 56 % of days at one site and 73 % at the other. Both methods indicated both sites as net sources of CH 4 and N 2 O. Mean emission rates for 1 year at the unfertilised, winter-grazed site were 8.9 (±0.79) nmol CH 4 m −2 s −1 and 0.38 (±0.018) nmol N 2 O m −2 s −1 . During the same year, mean emission rates at the irrigated, fertilised and rotationally grazed site were 8.9 (±0.79) nmol CH 4 m −2 s −1 and 0.58 (±0.020) nmol N 2 O m −2 s −1 . At this site, the N 2 O emissions amounted to 1.21 (±0.15) % of the nitrogen inputs from animal excreta and fertiliser application.

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“…Burchill et al . () reported that winter N 2 O emissions from a pasture soil were low when soils were poorly drained because in winter, evaporation is low and thus poorly drained soils are more likely to be completely saturated resulting in greater N 2 O reductase activity (Hamonts et al . ; Hansen et al .…”

Section: Factors Controlling the Magnitude Of N2o Emissions From Grazmentioning

confidence: 99%

“…Similarly, Burchill et al . () continuously measured the N 2 O emissions from a pasture for 3 years and observed winter N 2 O emissions were higher after an unusually cold period (maximum daily air temperature was <0°C for a period of 6 days) with soil freeze/thaw events. During a normal year, the maximum daily temperature remains above 0°C even during winter at this experimental site although the minimum daily temperature was <0°C for winter in a normal year.…”

Section: Factors Controlling the Magnitude Of N2o Emissions From Grazmentioning

confidence: 99%

Nitrous oxide emissions from pastures during wet and cold seasons

Uchida

Clough

2015

Grassland Science

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Grazed pastures contribute significantly to the global nitrous oxide (N 2 O) budget. In grazed pastures, the highest N 2 O emission rates are often reported during winter when soils are wet. This review discusses the current knowledge about factors controlling winter N 2 O emissions in grazed pastures. High N 2 O emissions from pastures during winter are also observed from winter-housed animal feeding systems. At near-zero temperature, N 2 O producing microbial activity is limited but some soil microbial communities adjust to low temperature better than others. Soil microbiological studies focusing on the identification of cold-tolerant denitrifiers and/or changes in microbial community structures under cold conditions are required. In winter-grazed pastures, the availability of substrates, such as nitrate (NO À 3 ) and labile organic carbon (C), for soil microbes producing N 2 O is influenced by factors such as animal wintering system, effluent management systems and plant activity. When animals are housed, N 2 O emissions during the winter storage of manures and the emissions after their application are important contributors to N 2 O inventories. The activity of pasture during winter and its relationship to N 2 O emissions requires further study in order to understand the competition between plants and N 2 O producing microbes for nitrogen, and the role of root exudation. Additionally, the effect of low temperatures on nutrient availability under urine patches is still not well known. The reduction of N 2 O to dinitrogen is regulated by an enzyme N 2 O reductase and its encoding gene (nosZ) expression needs to be studied in more detail to investigate the mechanisms behind winter N 2 O emissions. To mitigate N 2 O emissions during winter, restricted grazing regimes and the use of nitrification inhibitors have been studied; however, little is known about the effectiveness of these methods in mitigating N 2 O emissions during freeze/thaw cycles and during periods of snow-cover.

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Interannual variation in nitrous oxide emissions from perennial ryegrass/white clover grassland used for dairy production

Cited by 43 publications

References 46 publications

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

Combining two complementary micrometeorological methods to measure CH<sub>4</sub> and N<sub>2</sub>O fluxes over pasture

Nitrous oxide emissions from pastures during wet and cold seasons

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Interannual variation in nitrous oxide emissions from perennial ryegrass/white clover grassland used for dairy production

Cited by 43 publications

References 46 publications

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

Combining two complementary micrometeorological methods to measure CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O fluxes over pasture

Nitrous oxide emissions from pastures during wet and cold seasons

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Combining two complementary micrometeorological methods to measure CH<sub>4</sub> and N<sub>2</sub>O fluxes over pasture