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Review and update of a Nutrient Transfer model used for estimating nitrous oxide emissions from complex grazed landscapes, and implications for nationwide accounting

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posted on 2023-12-13, 02:42 authored by Ronaldo VibartRonaldo Vibart, Donna Giltrap, Surinder Saggar, Alec MackayAlec Mackay, Keith Betteridge, Des Costall, Mike RolloMike Rollo, Ina Draganova

In New Zealand, nitrous oxide emissions from grazed hill pastures are estimated using different emission factors for urine and dung deposited on different slope classes. Allocation of urine and dung to each slope class needs to consider the distribution of slope classes within a landscape and animal behavior. The Nutrient Transfer (NT) model has recently been incorporated into the New Zealand Agricultural GHG Inventory Model to account for the allocation of excretal nitrogen (N) to each slope class. In this study, the predictive ability of the transfer function within the NT model was explored using urine deposition datasets collected with urine sensor and GPS tracker technology. Data were collected from three paddocks that had areas in low (<12°), medium (12–24°), and high slopes (>24°). The NT model showed a good overall predictive ability for two of the three datasets. However, if the urine emission factors (% of urine N emitted as N2O–N) were to be further disaggregated to assess emissions from all three slope classes or slope gradients, more precise data would be required to accurately represent the range of landscapes found on farms. We have identified the need for more geospatial data on urine deposition and animal location for farms that are topographically out of the range used to develop the model. These new datasets would provide livestock urine deposition on a more continuous basis across slopes (as opposed to broad ranges), a unique opportunity to improve the performance of the NT model.

Funding

Ministry for Primary Industries Greenhouse Gas Inventory Research Fund (Agreement No. 406447)

History

Rights statement

© 2022 The Authors. Journal of Environmental Quality © 2022 American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Publication date

2022-05-28

Project number

  • Non revenue

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

John Wiley & Sons Ltd

Journal title

Journal of Environmental Quality

ISSN

0047-2425

Volume/issue number

51(5)

Page numbers

930-940

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