Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists surprised at persistence of nitrate from dated experiment

11.12.2003


An analysis of ground water and stream pollution 30 years after an agricultural study of nitrate began suggests that nitrate fertilizer can influence the watershed for decades.



Nitrate pollution from agricultural fertilizers can make water unsafe to drink, and may be causing a "dead zone" near the outlet of the Mississippi River in the Gulf of Mexico. For these reasons, farmers are being encouraged to alter their practices to use nitrogen more efficiently, but environmental improvements from these new practices have been difficult to document using short, two-to-four-year experiments. Some new findings are showing why.

An agricultural experiment concluded nearly 30 years ago is still influencing concentrations of nitrate in ground water and stream flow draining from a 74-acre field in western Iowa, according to scientists at the National Soil Tilth Laboratory, Ames, Iowa.


"Scientists are trained to study agricultural practices over several years to obtain conclusive data on how agricultural production is affected, but we are realizing the environmental effects of those practices take even longer to assess. The benefits of improved practices may take many years to be fully understood and realized," says Mark Tomer a scientist with the USDA Agricultural Research Service.

In an experiment conducted from 1969-1974, triple-rate fertilizer applications were made on a field forming the watershed for a small stream in western Iowa. The movement of a large pulse of nitrate into the deep soils was tracked in follow-up studies, conducted up to 10 years later. But years later, scientists were surprised when they detected evidence of the same pulse of nitrate at a 60-foot depth when setting up to monitor ground water at the site in 1996.

"We were initiating a new cropping-systems experiment, not attempting to follow up the old research," says Tomer. "The scientists who began the original experiment in 1969 have already retired."

In order to confirm the deep nitrate could originate from the old experiment, ground water flow rates and ages were investigated. The movement of the nitrate pulse to depth was also compared to stream flow records. The results provided three independent lines of evidence; all suggesting that water carrying the nitrate takes decades to flow through the subsurface of the watershed to the stream.

"We wanted to show the recommended cropping-system treatments begun in 1996 could improve water quality, but we won’t be able to do that by monitoring this stream, because the newer experiment is confounded by a persistent effect of past research. While this is disappointing, the lesson we have learned about how patient we must be in conducting research on agricultural pollution is eye opening,"

Results of the study are published in the November/December 2003 issue of the Journal of Environmental Quality. Subscribers can access the full article; nonsubscribers can access the abstract, or pay a $5 per-article fee, or buy a $15, 14-day site pass, at: http://jeq.scijournals.org/cgi/content/abstract/32/6/2158.


The Journal of Environmental Quality, http://jeq.scijournals.org is a peer-reviewed, international journal of environmental quality in natural and agricultural ecosystems published six times a year by the American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and the Soil Science Society of America (SSSA). The Journal of Environmental Quality covers various aspects of anthropogenic impacts on the environment, including terrestrial, atmospheric, and aquatic systems.

The American Society of Agronomy (ASA) http://www.agronomy.org, the Crop Science Society of America (CSSA) http://www.crops.org and the Soil Science Society of America (SSSA) http://www.soils.org are educational organizations helping their 10,000+ members advance the disciplines and practices of agronomy, crop, and soil sciences by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services

Sara Uttech | EurekAlert!
Further information:
http://jeq.scijournals.org/cgi/content/abstract/32/6/2158
http://www.agronomy.org
http://www.crops.org

More articles from Agricultural and Forestry Science:

nachricht Plasma-zapping process could yield trans fat-free soybean oil product
02.12.2016 | Purdue University

nachricht New findings about the deformed wing virus, a major factor in honey bee colony mortality
11.11.2016 | Veterinärmedizinische Universität Wien

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

IHP presents the fastest silicon-based transistor in the world

05.12.2016 | Power and Electrical Engineering

InLight study: insights into chemical processes using light

05.12.2016 | Materials Sciences

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>