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A risk index tool to minimize the risk of nitrogen loss from land to water

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posted on 2025-01-21, 00:53 authored by Rich McDowellRich McDowell, Val SnowVal Snow, Reina Tamepo, Linda Lilburne, Rogerio Cichota, Kohji Muraoka, Elizabeth Soal

Simple models can help reduce nitrogen (N) loss from land and protect water quality. However, the complexity of primary production systems may impair the accuracy of simple models. A tool was developed that assessed the risk of N loss as the product of N source inputs and relative transport by leaching and runoff. A dynamic process-based model was used to estimate the long-term monthly N loss risk by leaching and runoff in response to the interaction of static biophysical factors like soil type, slope, and long-term climate. Source inputs included dung and urine (from livestock), fertilizer, crop residues, and soil erosion. Estimates of the rank of N loss risk were related (r2 = 0.69, p < 0.001) to 96 observations of N loss (kg ha-1 year-1) across nine land uses; all but two of the observations fell within 95% prediction intervals. Across land uses, leaching accounted for 84% of N loss risk. Additional observations are needed to determine if N loss risk is representative of short-rotation vegetables and to account for potential lag times between calculated and measured losses. The good performance of the tool suggests that when displayed spatially, the tool can be used to target high-risk areas with actions to reduce the risk of N loss and the likelihood of water quality impairment.

Funding

Funded by the New Zealand Ministry for Business, Innovation and Employment’s Our Land and Water National Science Challenge (Toitū te Whenua, Toiora te Wai), as part of the project Linking Legacies to Wai

History

Rights statement

© 2024 The Author(s). Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of 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 originalwork is properly cited.

Publication date

2024-12-16

Project number

  • Non revenue

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

Wiley

Journal title

Journal of Environmental Quality

ISSN

0047-2425

Volume/issue number

54(1)

Page numbers

233-245

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