Navigation Links
Nitrogen mysteries in urban grasslands
Date:10/13/2009

MADISON, WI, OCTOBER 12, 2009 Areas of turf-forming species created and maintained by humans for aesthetic and recreational (not grazing) purposes, i.e. "urban grasslands" are an extremely common, but poorly studied ecosystem type. There are over 150,000 km2of urban grasslands in the U.S. and many receive high rates of fertilizer, creating concerns about nutrient runoff to streams, lakes, and estuaries and emissions of greenhouse gases such as nitrous oxide (N2O) to the atmosphere. Most turfgrass research has been done on highly controlled research plots which can be very different than actual urban grasslands which have highly variable management regimes and physical, biological, and chemical conditions.

In the Baltimore Ecosystem Study (BES, http://beslter.org), one of two urban components of the U.S. National Science Foundation (NSF) Long Term Ecological Research (LTER) network, scientists from the Cary Institute of Ecosystem Studies (Peter Groffman), the U.S. Forest Service (Richard Pouyat, Ian Yesilonis) and the University of North Carolina (Lawrence Band) established a series of long-term study plots to evaluate multiple ecological variables in different components of the urban landscape. An NSF-funded Research Experience for Undergraduates student (Candiss Williams) used these plots for a summer research project. Forest plots were established in urban and rural parks for comparison with grass plots that vary in management intensity, ranging from unfertilized and infrequently mowed to high levels of fertilizer and herbicide input and frequent mowing. Plots were instrumented with lysimeters to measure nutrient leaching losses, soil chamber bases for measuring soil/atmosphere fluxes of N2O, and sensors for soil temperature and moisture. Results on nitrate (NO3-) leaching and N2O fluxes over a period of significant climatic variability (2001�) were presented in a paper in the SeptemberOctober 2009 issue of Journal of Environmental Quality.

Differences in NO3- leaching and N2O flux between forests and grasslands were not as high as expected given the higher frequency of disturbance and fertilization in the grasslands. Annual NO3- leaching was usually higher in grass than forest plots, but in a very dry year and when a disturbed forest plot was included in the analysis, differences were small and insignificant. There were few differences in N2O between grass and forest plots, and markedly higher fluxes in wet years. In a dry year, N losses from the grasslands were equal to less than 10% of the amount of N applied in fertilizer, and even in a wet year, losses were less than 40%. Lots of N appears to be retained in urban grasslands, likely because they support rapidly growing vegetation and high stocks of soil organic matter.

While surprising, these results do not suggest that we should not be concerned about the environmental impacts of urban grasslands. If leaching losses equal 40% of the amount of N applied in fertilizer, and high rates of fertilizer (e.g., 200 kg N ha-1 yr-1) are applied, lawns will have a strongly negative effect on receiving water quality. However, our results suggest that urban grasslands have considerable capacity for N retention that should be studied and considered in evaluations of land-use change and in the development of management plans for urban and suburban watersheds.

The full article is available for no charge for 30 days following the date of this summary. View the abstract at http://jeq.scijournals.org/cgi/content/abstract/38/5/1848.

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) www.agronomy.org, is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.


'/>"/>
Contact: Sara Uttech
suttech@agronomy.org
608-268-4948
American Society of Agronomy
Source:Eurekalert

Related biology news :

1. Planets nitrogen cycle overturned by tiny ammonia eater of the seas
2. Is nitrogen the new carbon?
3. Nitrogen fixation and phytoplankton blooms in the southwest Indian Ocean
4. Ozone, nitrogen change the way rising CO2 affects Earths water
5. Nitrogen research shows how some plants invade, take over others
6. UC Davis begins $2.8 million in studies of agricultural nitrogens impacts
7. Illinois Soil Nitrogen Test measures microbial nitrogen
8. Tree species composition influences nitrogen loss from forests
9. Researchers call for nitrogen and phosphorus reductions to combat eutrophication in aquatic systems
10. Cropland diversity reduces nitrogen pollution
11. Lichens function as indicators of nitrogen pollution in forests
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:8/23/2017)... -- The general public,s help is being enlisted in what,s thought to be ... on the human body –and are believed to affect health.  ... The Microbiome Immunity Project is the largest study ... gut. The project's goal is to help advance scientific knowledge of the ... ...
(Date:6/30/2017)... Today, American Trucking Associations announced Seeing ... and eye tracking software, became the newest member ... "Artificial intelligence and advanced sensing algorithms ... driver,s attentiveness levels while on the road.  Drivers ... fatigue and prevent potential accidents, which could lead ...
(Date:5/23/2017)...  Hunova, the first robotic gym for the rehabilitation and functional motor ... Genoa, Italy . The first 30 robots will be ... USA . The technology was developed and patented at the ... spin-off Movendo Technology thanks to a 10 million euro investment from entrepreneur ... ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... ... States multicenter, prospective clinical study that demonstrates the accuracy of the FebriDx® ... identifying clinically significant acute bacterial and viral respiratory tract infections by testing ...
(Date:10/11/2017)... ... October 11, 2017 , ... At its ... announced Dr. Suneel I. Sheikh, the co-founder, CEO and chief research scientist of ... been selected for membership in ARCS Alumni Hall of Fame . ASTER ...
(Date:10/11/2017)... ... 2017 , ... Proscia Inc ., a data solutions ... “Pathology is going digital. Is your lab ready?” with Dr. Nicolas Cacciabeve, Managing ... how Proscia improves lab economics and realizes an increase in diagnostic confidence.* ...
(Date:10/11/2017)... ... October 11, 2017 , ... A new study published ... frozen and fresh in vitro fertilization (IVF) transfer cycles. The multi-center ... success. , After comparing the results from the fresh and frozen transfer cohorts, ...
Breaking Biology Technology: