Show simple item record  

dc.contributor.authorMudge, Paul Lawrence
dc.contributor.authorSchipper, Louis A.
dc.contributor.authorGhani, A.
dc.contributor.authorUpsdell, M.
dc.contributor.authorBaisden, W. Troy
dc.date.accessioned2013-06-06T02:55:56Z
dc.date.available2013-06-06T02:55:56Z
dc.date.copyright2013
dc.date.issued2013
dc.identifier.citationMudge, P. L., Shipper, L. A., Ghani, A., Upsdell, M. & Baisden, W. T. (2013). Changes in natural ¹⁵n abundance in pastoral soils receiving differing amounts of superphosphate fertilizer and irrigation for 50 years. Soil Biology & Biochemistry, 77(3), 830-841en_NZ
dc.identifier.urihttps://hdl.handle.net/10289/7683
dc.description.abstractIntensification of pastoral agriculture has led to increased N losses to the wider environment. This has led to an emphasis on improving our understanding of soil N dynamics, and development of management practices which mitigate N losses. The natural abundance of the stable isotope δ¹⁵N relative to ¹⁴N (δ¹⁵N) in soils can provide an integrated measure of past N cycle processes, and in particular soil δ15N can reflect past N losses, because during most N transformation processes 14N is preferentially lost. We therefore hypothesized that pastoral soils under intensive management regimes (with high N inputs, cycling, and loss) would become progressively enriched with ¹⁵N relative to soils under less intensive management. To test this hypothesis we analyzed archived surface soils from two long-term grazed field trials in New Zealand, where different rates of irrigation and superphosphate fertilizer had been applied for ∼50 yr. In all treatments except one (a control treatment receiving no fertilizer), δ¹⁵N increased with time and the increase was greater in treatments receiving more superphosphate or irrigation (average increases ranged from ∼0.015–0.034 ‰ yr–1). Pasture production and grazing intensity also increased with increasing fertilizer rate and irrigation frequency, and we found positive correlations between the average rate of change in soil δ¹⁵N, and total pasture production (r² = 0.77, p = 0.02), clover production (r² = 0.95, p < 0.001), and calculated N losses (r² = 0.98, p < 0.001) over ∼50 yr. We suggest that most of the difference in δ¹⁵N observed between treatments was due to the influence fertilizer and irrigation had on pasture production, and the resulting effects this had on isotope fractionating N loss processes. Soil δ¹⁵N could therefore be a useful indicator of past management intensity and N cycling and loss from pastoral systems.en_NZ
dc.language.isoenen_NZ
dc.publisherSoil Science Society of Americanen_NZ
dc.relation.ispartofSoil Science Society of America Journal
dc.relation.urihttps://www.soils.org/publications/sssaj/abstracts/77/3/830en_NZ
dc.titleChanges in natural ¹⁵n abundance in pastoral soils receiving differing amounts of superphosphate fertilizer and irrigation for 50 yearsen_NZ
dc.typeJournal Articleen_NZ
dc.identifier.doi10.2136/sssaj2012.0333en_NZ
dc.relation.isPartOfSoil Science Society of America Journalen_NZ
pubs.begin-page830en_NZ
pubs.elements-id38434
pubs.end-page841en_NZ
pubs.issue03en_NZ
pubs.volume77en_NZ


Files in this item

FilesSizeFormatView

There are no files associated with this item.

This item appears in the following Collection(s)

Show simple item record