New Delhi: Nitrogen fertilisers help crop plants grow faster, and allow agricultural land to be used more efficiently. But, these fertilisers can pollute our water for decades when applied in excess.
A new study, conducted by researchers at University of Waterloo in Ontario, Canada, suggests six steps to address nitrogen pollution and improve water quality. The study, titled "Managing Nitrogen Legacies to Accelerate Water Quality Improvement", was recently published in the journal, Nature Geoscience.
Nitrogen persists for long, and hence, management efforts may seem futile. However, the new study provides a roadmap for scientists, policymakers, and the public to overcome the challenges associated with legacy nitrogen for faster improvements to our water quality.
What Is Legacy Nitrogen?
Widespread decreases in nitrate loads in the rivers and streams of several regions, such as the United States, remain elusive, despite the tremendous effort invested in reducing the use of nitrogen. The slow release to streams of nitrogen that has accumulated in ground water and other storage areas is known as legacy nitrogen.
"We have to think about the legacy we leave for the future in a strategic way from both the scientific and socio-economic angles," Nandita Basu, the lead author of the study, was quoted as saying in a statement issued by University of Waterloo. She said that this is a "call to action for us to accept that these legacies exist and figure out how to use them to our advantage."
Six Steps Recommended By The Study
The study recommends six steps to improve water quality and address nitrogen pollution, which include focusing research to quantify the length of time the nitrogen stays in our ecosystems, finding ways to use the legacy nitrogen as a resource for growing crops, combining conservation methods, among others.
Following are the six steps:
- One must focus research to quantify the length of time the nitrogen stays in our ecosystems. This will help adjust one's expectations for conservation timelines.
- People must find ways to use the legacy nitrogen as a resource for growing crops. This should be done instead of adding new nitrogen fertilisers to our ecosystems with already high levels of nitrogen.
- Instead of a widespread blanket approach, one must target conservation strategies to get the maximum water quality improvement.
- People must combine conservation methods that reduce the amount of nitrogen which has already left the farm fields. For instance, in wetlands, conservation methods can be combined with the methods that harvest nitrogen from past legacies accumulated in the soil.
- One must monitor 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.
- Both short- and long-term cost-benefit analyses must be incorporated when assessing the economic impacts of conservation strategies.
Different parents of the world have different nitrogen legacies, depending on the climate and historical land use, and land management patterns. Measurements and monitoring have not yet been widespread enough to understand these differences and support water quality policies, though theoretical knowledge of these legacies has existed for decades, according to the study.
Basu said that one must stop treating nitrogen legacies as the elephant in the room. Instead, watershed management that can address these past legacies must be designed.
"We need to ask ourselves how we can do better for the future," the statement quoted her as saying.