Spatial regression models were used to predict yields of nitrogen (N) and phosphorus (P) discharged from catchments throughout New Zealand. The models were derived using loads (kg yr‚àí1) of TN, NO3-N, TP and DRP calculated for 592 river water quality monitoring sites. Anthropogenic increases in loads of TN, NO3-N, TP and DRP exported to the ocean were 74%, 159%, 48% and 18%, respectively. Increases in loads varied considerably at smaller scales, between 4- and 26-fold for N and 6- to 9-fold for P. Predictions of yields and loads have utility in the development of strategies to manage nutrients.
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 project Land Use Suitability|Assessing Contaminants with Stream Order
History
Publication date
2017-10-07
Language
English
Does this contain Māori information or data?
No
Journal title
New Zealand Journal of Marine and Freshwater Research