Tracing nitrate in watersheds

Mar 15, 2013

Plants need nitrogen to grow, and nitrate is a common fertilizer ingredient, but high levels of nitrate contamination in drinking water sources can cause health problems. It is generally known that nitrogen flows through watersheds from upslope areas down to streams, but the relationships between upslope soil solution or groundwater nitrate concentrations and stream water nitrate levels—and the ways in which land use changes may alter this relationship—are not fully understood.

Sudduth et al. analyzed published studies of 62 watersheds to see if a consistent relationship between upslope soil solution or groundwater and nitrate concentrations exists and whether ecosystem disturbances such as fire or land use changes such as clearing forests for agriculture or affected the relationship between soil and stream water nitrate concentrations.

For 40 undisturbed forest watersheds and 10 disturbed forest watersheds, they find that stream water nitrate concentrations are typically about half that of soil solution nitrate concentrations, indicating that a significant amount of nitrate is removed as water passes through watersheds to streams. For the 12 watersheds in their study that had significant agricultural or urban development, there is less reduction in nitrate concentrations between soil solutions and stream waters, suggesting that in human-dominated landscapes, upland soils and riparian zones are less efficient at removing nitrate than in undisturbed ecosystems.

The study suggests that, in general, stream water nitrate concentrations can provide an indication of upland soil solution or groundwater nitrate levels. The authors conclude that undisturbed watersheds have a significant capacity to remove nitrate, but land use changes tend to diminish the efficiency of nitrate removal from watersheds or alter the flow paths of nitrate.

Explore further: Pact with devil? California farmers use oil firms' water

More information: Nitrate in watersheds: Straight from soils to streams? Journal of Geophysical Research-Biogeosciences, doi:10.1002/jgrg.20030, 2013 http://onlinelibrary.wiley.com/doi/10.1002/jgrg.20030/abstract

Related Stories

Is your drinking water safe?

Feb 28, 2008

Lake Bloomington is a major source of drinking water for residents of Bloomington, IL, and has a history of nitrate concentrations that exceed safe levels. Because Lake Bloomington has a record of elevated nitrate levels, ...

Nitrate fertiliser wasted on sugarcane

May 09, 2011

(PhysOrg.com) -- Rising nitrogen fertiliser application to sugarcane crops globally and the potential for this fertiliser to be leached from soil and lost to the atmosphere have been highlighted in a new study led by The ...

Prairie restoration also helps restore water quality

Mar 08, 2012

U.S. Department of Agriculture (USDA) scientists are studying the overall improvement in water quality when native prairie vegetation is restored to fields once cropped with corn and soybeans. Agricultural ...

Melting snow provides clues for acidification

Feb 15, 2008

In forests of the northeastern United States, sulfate and nitrate are the dominant dissolved forms of sulfur and nitrogen in precipitation. In winter, these acidic agents accumulate in the snowpack and are released to groundwater ...

Dutch researcher develops catalysts for clean drinking water

Jun 18, 2010

Jitendra Kumar Chinthaginjala of the University of Twente, The Netherlands, has developed a catalyst that can efficiently remove nitrite and nitrate from drinking water. These two toxic substances are increasingly found in ...

Recommended for you

Gimmicks and technology: California learns to save water

Jul 03, 2015

Billboards and TV commercials, living room visits, guess-your-water-use booths, and awards for water stinginess—a wealthy swath of Orange County that once had one of the worst records for water conservation ...

Cities, regions call for 'robust' world climate pact

Jul 03, 2015

Thousands of cities, provinces and states from around the world urged national governments on Thursday to deliver a "robust, binding, equitable and universal" planet-saving climate pact in December.

Will climate change put mussels off the menu?

Jul 03, 2015

Climate change models predict that sea temperatures will rise significantly, including in the tropics. In these areas, rainfall is also predicted to increase, reducing the salt concentration of the surface ...

As nations dither, cities pick up climate slack

Jul 02, 2015

Their national governments hamstrung by domestic politics, stretched budgets and diplomatic inertia, many cities and provinces have taken a leading role—driven by necessity—in efforts to arrest galloping ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.