Ledgard, Sterwart F.

Luo, Jiafa

Saggar, Surinder

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Non‐CO2 Greenhouse Gas Emissions Associated with Winter Management and Farm Effluent Application in Grazed Grassland Systems in New Zealand Jiafa Luo AgResearch, New Zealand Surinder Saggar Landcare Research, New Zealand Sterwart F. Ledgard AgResearch, New Zealand Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/8-1/24 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]892　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　Grasslands/Rangelands Resources and Ecology ——— Climate Change and Impact on Grasslands/RangelandsNon‐CO2 greenhouse gas emissions associated with winter management and farm effluentapplication in grazed grassland systems in New ZealandJ . L uo1 , S . Saggar2 , S .F . Ledgard11 A gResearch , Ruakura Centre , Priv ate Bag 3123 , H amilton , New Zealand , E‐mail : j ia f a . luo ＠ agresearch .co .nz .2 L andcare Research , Priv ate Bag 11052 , Palmerston North , New ZealandKey words :Nitrous oxide , methane , stand‐off pad , farm effluent , pasture , grazing systemsIntroduction In New Zealand ,�stand‐off pads�( purpose built , drained loafing space to hold livestock for periods when it is notsuitable to have them on pasture) are increasingly used in restricted cattle grazing systems . These stand‐off pads are consideredto avoid damage to pasture , to minimise soil compaction and to reduce emissions of greenhouse gas nitrous oxide ( N２O ) andnitrate leaching during wet periods of the year . However , emissions of N２O and methane (CH４ ) also occur from stand‐off padsand from land applied farm effluent collected from stand‐off pads . Reducing the emissions from these sources is crucial to thedevelopment of successful restricted grazing strategies to reducing their environmental impact . Here we summarise the resultsof N２O and CH４ emissions measured from a stand‐off pad and also N２O emissions from effluent applied to two pastoral soilsunder contrasting soil moisture conditions .Materials and methods The stand‐off pad was used for holding ２１ non‐lactating cows for about １８ h per day ( following ６ hgrazing pasture) for ８６‐day period between late June and early August when soil was wet . The pad ( ３００ m２ ) consisted ofscreened crushed pine bark and sawdust and an effluent drainage collection system . The effluent from the stand‐off pad wasapplied onto a long‐term white clover / ryegrass based pasture on poorly‐drained Waikato Te Kowhai silt loam soil during thevery dry seasons of ２００４ and ２００５ . The farm effluent was also applied on poorly‐drained Tokomaru silt loam soil in theManawatu region three times between ２００３ and ２００４ . The effluent was applied at N loadings between １６ and ５０ kg N ha‐１ perapplication . Measurements of N２O and CH４ fluxes originating from the stand‐off pad were made while it was being used ( Luoet al . ２００８a) . N２O emissions were also measured from the effluent applied and control sites using large numbers of staticchambers ( Luo et al . ２００８b) .Results and discussion Nitrous oxide fluxes from the stand‐off pad ranged between ０ and ３ .０ g N２O‐N day‐１ and were probablyrelated to the concentrations of water and nitrate in the pad materials . Overall only ５４ g of N２O‐N was emitted from the stand‐off pad supporting ２１ cows for the June‐August , ８６‐day period , representing about ０ .０１％ of the excreta N deposited on thepad . Methane fluxes from the stand‐off pad were between ０ and ３６０ g CH４‐C day‐１ , and were related to the amount ofaccumulated dung on the pad surface over time . Methane emissions from the pad during the measurement period were ３ .０ kgCH４‐C , and the CH４ emission value was ２ .３４ g CH４ / kg excretal C deposited on the pad . Application of effluent to grazedpastures increased N２O fluxes compared to the control . N２O emissions from effluent applications were most strongly influencedby soil water‐filled pore space (WFPS) and excretal‐N inputs through grazing , and ranged from ０ .０１ to ４ .９３％ of the effluentN ( Table １) . N２O emissions were higher when pastures were grazed and soil WFPS was above field capacity , while emissionswere lower when pastures were not grazed and soil WFPS was much below field capacity .Table 1 N itrogen ap p lied through f arm ef f luent and N 2O emissions ( Luo et al . 2008b) .Location Application time Soil WFPS ( ％ ) N applied( kg N ha‐１ )N２O emitted( kg N２O‐N ha‐１ )Emission factor( ％ )Waikato Apr ２００４ �３０‐５３ 行５０ 侣.０ ０ .０１５ ０ l.０３Waikato Feb ２００５ 趑２６‐３８ 行５０ 侣.０ ０ .００４ ０ l.０１Manawatu Sep ２００３ 铑６１‐９０ 行２３ 侣.９ ０ .４７１ １ l.９７Manawatu Jan ２００４ 沣６９‐９４ 行２５ 侣.２ １ .２４３ ４ l.９３Manawatu Feb ２００４ 趑５６‐７７ 行１８ 侣.０ ０ .４４９ ２ l.４９Conclusions The use of stand‐off pads in New Zealand during winter when soil is wet and strategic application of farm effluentduring summer and autumn when soil is dry can significantly reduce N２O emission from grazed pastures . Delaying effluent‐application after grazing events could further reduce N２O by reducing the levels of surplus mineral‐N . Emissions of CH４ f romeffluent‐application are needed to determine for assessment of effects of using stand‐off pads and restricted grazing on totalemissions of greenhouse gas from �whole" systems .ReferencesLuo J , Ledgard SF , Lindsey SB (２００８a) A test of a winter farm management option for mitigating nitrous oxide emissions froma dairy farm .Soil Use and Management , ( in press) .Luo J , Saggar S , Bhandral R , Bolan , N , Ledgard SF , Lindsey SB ( ２００８b) Effects of irrigating dairy‐grazed grassland withfarm dairy effluent on nitrous oxide emissions . Plant and Soil , ( under review ) .

Non‐CO\u3csub\u3e2\u3c/sub\u3e Greenhouse Gas Emissions Associated with Winter Management and Farm Effluent Application in Grazed Grassland Systems in New Zealand

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=2938&amp;context=igc

Non‐CO\u3csub\u3e2\u3c/sub\u3e Greenhouse Gas Emissions Associated with Winter Management and Farm Effluent Application in Grazed Grassland Systems in New Zealand

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