Navigation Links
Cropland diversity reduces nitrogen pollution
Date:2/11/2009

Researchers have identified a link between the diversity of crops grown in farmlands and the pollution they create in lakes and rivers. In a Frontiers in Ecology and the Environment e-View paper, ecologists show that when the biodiversity of crops is high, less dissolved nitrogen is found exiting the surrounding watersheds.

Nitrogen from agricultural fertilizers leaches through soils to groundwater and runs off into rivers and lakes, increasing aquatic dissolved nitrate. Too much nitrate in the water can lead to prolific growth of aquatic algae, which can use up most of a water body's oxygen when they die and are decomposed, creating "dead zones" that cannot support life.

Whitney Broussard of the University of Louisiana at Lafayette and R. Eugene Turner of Louisiana State University at Baton Rouge compiled data from the past 100 years on watersheds varying in size from the Illinois Cache River basin (400 square miles) to the Mississippi River Basin (more than a million square miles). The researchers compared this watershed data with land-use practices since the early 1900s.

The results show that since the beginning of the last century, the average farm size in the United States has doubled and the number of farms has fallen by almost two-thirds. Broussard also says that a shift from farm animals and simple plows to the use of machines to till croplands has changed not only the culture but the environmental impact of farming.

"With the growing American farm comes the necessity to use more industrialized means of farming," says Broussard. "Our agricultural practices have always impacted water quality, but over the past century the mechanization of agriculture and the use of more potent fertilizers has caused a greater effect: the nitrogen leakage rate is higher."

Modern farms tend to produce fewer crop varieties; this lower crop biodiversity can negatively impact surrounding watersheds. According to the study, within a given area, a higher biodiversity of crops led to less dissolved nitrogen in surrounding water bodies. The explanation for this phenomenon, Broussard says, is difficult to discern.

"Diverse farms tend to have smaller fields with more edges, which can mean there's a greater buffering effect on nitrogen runoff by surrounding grasslands or woodlands," he says.

The researchers' results also showed that since 1906, the average aquatic nitrate concentration increased threefold in the entire U.S. and tenfold in the Iowa, Des Moines, and Minnesota Rivers, all of which fall in heavily tilled agricultural areas.

In areas where farming is scarce or absent, however, the authors found no perceptible change in dissolved nitrogen concentrations since the early 1900s. Broussard thinks this indicates that the impacts might be reversible if policy changes included incentives for farmers to rotate more crops, decrease their field size, increase the edges of fields and sizes of buffering zones, and incorporate more native perennial grasses into farms and in between fields.

"There has been great progress made to reduce the footprint of agriculture, but there is still room for improvement," says Broussard. "The American farmer is caught in a mode of production that has tremendous momentum and cannot be changed on the farm it's a policy question now."


'/>"/>

Contact: Christine Buckley
christine@esa.org
202-833-8773
Ecological Society of America
Source:Eurekalert

Related biology news :

1. Biodiversity itself begets a species cascade, researchers say
2. The global impact of climate change on biodiversity
3. Alpine rivers hold important clues for preserving biodiversity and coping with climate change
4. Networks of small habitat patches can preserve urban biodiversity
5. Latin American Science Initiative Puts Tropical Rainforest Diversity Online
6. Marine invasive species advance 50 km per decade, World Conference on Marine Biodiversity told
7. Marine invasive species advance 50km per decade, World Conference on Marine Biodiversity told
8. Study confirms amphibians ability to predict changes in biodiversity
9. European biodiversity and ecosystem scientists merge and gear up for long-term research
10. Diversity of trees in Ecuadors Amazon rainforest defies simple explanation
11. DFG continues to strengthen biodiversity research
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/24/2017)... Janice Kephart , former 9/11 ... Partners, LLP (IdSP) , today issues the following ... March 6, 2017 Executive Order: Protecting the ... be instilled with greater confidence, enabling the reactivation ... applications are suspended by until at least July ...
(Date:4/13/2017)... , April 13, 2017 UBM,s Advanced Design ... will feature emerging and evolving technology through its ... Summits will run alongside the expo portion of the ... panels and demonstrations focused on trending topics within 3D ... design and manufacturing event will take place June 13-15, 2017 ...
(Date:4/11/2017)... , April 11, 2017 No ... but researchers at the New York University Tandon ... of Engineering have found that partial similarities between ... systems used in mobile phones and other electronic ... The vulnerability lies in the fact ...
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 , ... ... President Andi Purple announced Dr. Suneel I. Sheikh, the co-founder, CEO and ... Labs ), Inc. has been selected for membership in ARCS Alumni Hall ...
(Date:10/11/2017)... , ... October 11, 2017 , ... ... announced today it will be hosting a Webinar titled, “Pathology is going digital. ... Associates , on digital pathology adoption best practices and how Proscia improves lab ...
(Date:10/11/2017)... Austin, TX (PRWEB) , ... October 11, 2017 ... ... in August compared the implantation and pregnancy rates in frozen and fresh ... the contribution of progesterone and maternal age to IVF success. , After comparing ...
Breaking Biology Technology: