Estimating direct N2O emissions from sheep, beef, and deer grazed pastures in New Zealand hill country: accounting for the effect of land slope on N2O emission factors from urine and dung

dc.citation.volume205
dc.contributor.authorSaggar SK
dc.contributor.authorGiltrap DL
dc.contributor.authorDavison R
dc.contributor.authorGibson R
dc.contributor.authorde Klein CAM
dc.contributor.authorRollo M
dc.contributor.authorEttema P
dc.contributor.authorRys G
dc.date.available2015-07-01
dc.date.available2015-03-05
dc.date.issued2015-03
dc.description.abstractNearly one-half of New Zealand's ruminant livestock graze on hill country pastures where spatial differences in soil conditions are highly variable and excretal deposition is influenced by pasture production, animal grazing and resting behaviour that impact the nitrous oxide (N2O) emission factor from excreta (EF3). New Zealand currently uses country-specific EF3 values for urine and dung of 0.01 and 0.0025, respectively, to estimate direct N2O emissions from excreta. These values have largely been developed from trials on flat pastoral land. The use of the same EF3 for hill pasture with medium and steep slopes has been recognised as a possible source of overestimation of N2O emissions in New Zealand. The objectives of this study were to develop and describe an approach that takes into account the effects of slope in estimating hill country N2O emissions from the dung and urine of ruminant animals (sheep, beef cattle, and deer) across different slope classes, and then compare these estimates with current New Zealand inventory estimates. We use New Zealand as a case study to determine the direct N2O emissions between 1990 and 2012 from sheep, beef cattle and deer excreta using updated estimates of EF3 for sloping land, the area of land in different slope classes by region and farm type, and a nutrient transfer model to allocate excretal-N to the different slope classes, and compare the changes between these hill pastures-specific and current inventory estimates. Our findings are significant - the proposed new methodology using New Zealand specific EFs calculated from a national series of hill country experiments resulted in 52% lower N2O estimates relative to using current inventory emission factors, for the period between 1990 and 2012 and reduces New Zealand's total national agricultural N2O greenhouse inventory estimates by 16%. The improved methodology is transparent, and complete, and has improved accuracy of emission estimates. On this basis, the improved methodology of estimating N2O emission is recommended for adoption where hill land grasslands are grazed by sheep, beef cattle and deer.
dc.description.publication-statusPublished
dc.format.extent70 - 78 (9)
dc.identifierhttp://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000353748500008&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=c5bb3b2499afac691c2e3c1a83ef6fef
dc.identifier.citationAGRICULTURE ECOSYSTEMS & ENVIRONMENT, 2015, 205 pp. 70 - 78 (9)
dc.identifier.doi10.1016/j.agee.2015.03.005
dc.identifier.elements-id230769
dc.identifier.issn0167-8809
dc.languageEnglish
dc.publisherElsevier
dc.relation.isPartOfAGRICULTURE ECOSYSTEMS & ENVIRONMENT
dc.subjectScience & Technology
dc.subjectLife Sciences & Biomedicine
dc.subjectAgriculture, Multidisciplinary
dc.subjectEcology
dc.subjectEnvironmental Sciences
dc.subjectAgriculture
dc.subjectEnvironmental Sciences & Ecology
dc.subjectAnimal grazing and resting behaviour
dc.subjectCountry specific emissions
dc.subjectIPCC
dc.subjectNew methodology
dc.subjectNutrient transfer model
dc.subjectUNFCCC
dc.subjectNitrous oxide
dc.subjectNITROUS-OXIDE EMISSIONS
dc.subjectPHOSPHORUS
dc.subjectFRANCE
dc.subjectSULFUR
dc.subjectFATE
dc.subject.anzsrc05 Environmental Sciences
dc.subject.anzsrc07 Agricultural and Veterinary Sciences
dc.subject.anzsrc16 Studies in Human Society
dc.titleEstimating direct N2O emissions from sheep, beef, and deer grazed pastures in New Zealand hill country: accounting for the effect of land slope on N2O emission factors from urine and dung
dc.typeJournal article
pubs.notesNot known
pubs.organisational-group/Massey University
pubs.organisational-group/Massey University/College of Sciences
pubs.organisational-group/Massey University/College of Sciences/School of Agriculture & Environment
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