Researchers create six step guide to improve global water quality

nitrogen legacies
© Sean Pavone

The University of Waterloo have created six steps to improve water quality, address nitrogen pollution and examine nitrogen legacies

Nitrogen fertilisers are crucial in promoting crop growth and feeding the global population however when applied in excess it can pollute water for decades. This study from the University of Waterloo found in the Nature Geoscience journal, provides a step by step plan for scientists, policymakers, and the public to reduce the impact of long lasting nitrogen pollution and ensuring fast improvements to water quality on a global level.

“We have to think about the legacy we leave for the future in a strategic way from both the scientific and socio-economic angles,” said Nandita Basu, a professor of Earth and Environmental Sciences and Civil and Environmental Engineering at Waterloo and the study’s lead author.

“This is a call to action for us to accept that these legacies exist and figure out how to use them to our advantage.”

Previous efforts to manage nitrogen reduction have seen few results due to the amount of time nitrogen can be present in water – an effect known as nitrogen legacies. This has resulted in management efforts seeming futile and unattractive due to low results.

This is a key factor that research is suggesting governments attempt to tackle.

6 steps to improving water quality

Waterloo University researchers put forward their recommendation for 6 steps that governments and policymakers can undertake to make real changes.

  1. Focus research to quantify the length of time the nitrogen stays in our ecosystems to adjust our expectations for conservation timelines.
  2. Find ways to use the legacy nitrogen as a resource for growing crops instead of adding new nitrogen fertilizers to our ecosystems with already high levels of nitrogen.
  3. Target conservation strategies to get the maximum water quality improvement instead of a widespread blanket approach.
  4. Combine conservation methods that reduce the amount of nitrogen that has already left the farm fields, such as in wetlands, with methods that harvest nitrogen from past legacies accumulated in the soil.
  5. Monitor water quality at both large and small scales so that short-term results can be seen at scales like a farm field and long-term results downstream at river basins can also be tracked.
  6. When assessing the economic impacts of conservation strategies, incorporate both short- and long-term cost-benefit analyses.

Nitrogen legacies

Differing about the world, nitrogen legacies depend on the climate, historical land use and land management patterns.

While theoretical knowledge of these legacies has existed for decades, measurements and monitoring have not yet been thorough  or widespread enough to understand these differences and support water quality policies, where there is still an expectation of short-term water quality improvement.

“It’s time we stop treating nitrogen legacies as the elephant in the room and design watershed management strategies that can address these past legacies,” said Basu.

“We need to ask ourselves how we can do better for the future.”

Read the full study here.



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