Climate change likely to cause surge in nutrient runoff


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A small portion of a hypoxic dead zone in the Chesapeake Bay. (Chesapeake Bay Program)
Jenna Ladd| August 4, 2017

A recent study found that increased precipitation due to climate change will lead to markedly increased nutrient runoff.

Nitrogen rich fertilizers are widely used by U.S. farmers. Many times, more fertilizer than crops can use are applied to the land and the excess runs off into local waterways, eventually draining into the ocean. Excessive nutrient enrichment, also known as eutrophication, decreases available oxygen in the water and kills off aquatic species, resulting in “dead zones.”

Warmer temperatures associated with climate change are expected to continue producing heavier rainfall, thereby increasing nutrient runoff by up to twenty percent by 2100. Anna Michalak, a professor of global ecology at the Carnegie Institution for Science at Stanford and one of the authors of the study, told the New York Times, “When we think about climate change, we are used to thinking about water quantity — drought, flooding, extreme rainfall and things along those lines. Climate change is just as tightly linked to issues related to water quality, and it’s not enough for the water to just be there, it has to be sustainable.”

Researchers concluded that the Upper Mississippi Atchafalaya River Basin, the Northeast and the Great Lakes basin are likely to see the largest increases in nutrient runoff because these areas of the country are already creating hypoxic dead zones. Climate change will likely compound these effects.

While the study focused on the continental U.S., the researchers did apply their model to parts of the world most similar to it. They found that large areas of East, South and Southeast Asia will likely see nutrient runoff surges similar to those in the U.S. Given that some people in these regions depend on surface water to survive, the impacts of nutrient pollution there may be especially lethal.

Cover crop planting on the rise, but still used by just a small fraction of Iowa farmers


Iowa farmers planted 600,000 acres of cover crops last year. (flickr/CAFNR)

Katelyn Weisbrod | June 14, 2017

Iowa farmers planted 600,000 acres of cover crops last fall. This is an increase of over 60,000 acres, but covers just 2.6 percent of the 23.4 million acres of corn and soybean crops in the state.

Various state and federal conservation programs provided funding for 353,000 of these acres, including a cost-share program through the Iowa Department of Agriculture and Land Stewardship, as part of the Iowa Water Quality Initiative to meet the needs of the Iowa Nutrient Reduction Strategy.

Cover crops provide land with a vegetative cover during the months that crops are not actively growing, between the harvest and replanting. This helps to reduce the amount of nutrients that are washed into Iowa’s water bodies from agricultural lands, ultimately protecting the water quality. According to a report by the Environmental Working Group, cover crops can reduce the amount of nitrates leaching from the soil by 35 percent, and they are the the most effective practice for retaining nitrogen in the soil.

Washington County leads the state with the most acres of cover crops planted, followed by Cedar and Iowa counties, Wallaces Farmer reports.

Iowa Agriculture Secretary Bill Northey told Wallaces Farmer that he is encouraged by the increase in the practice.

“It’s obvious with the interest we’ve seen over the past few years that farmers are seeing the benefits that cover crops provide,” Northey said to Wallaces Farmer. “Cover crops are an important tool to help improve water quality and soil health in Iowa, and it is great to see an increasing number of farmers use this practice.”

Soybeans may play bigger role in nitrate levels than previously thought


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IIHR’s water-quality monitoring network has generated interesting data that contradicts some widely-held beliefs regarding corn and soybeans and their impact on nitrate in Iowa’s streams. (IIHR)
Jake Slobe | September 28, 2016

New research shows that soybeans may play a key role in the transport of nitrate from farmed fields to the stream network.

As Iowa farmers have planted more acres of corn to meet the increasing demand, many models predicted that nitrate concentrations in Iowa streams would increase as a consequence. However, a new study conducted by the UI’s IIHR-Hydroscience & Engineering group and the Iowa Soybean Association, published in the Journal of Soil and Water Conservation, challenges many of these predictions.

As the amount of corn planted increased and the amount of soybeans decreased, fertilizer application increased by 24 percent in the watershed. Surprisingly, the nitrate levels in the river saw no increase and in some cases saw slight decreases.

The study evaluated 7,000 water samples in the Raccoon River Watershed from 1999- 2014 and had access to fertilization data for 700 fields in the watershed. The result from the study has led researchers to believe that nitrate levels are less dependent on corn production than previously thought.

IIHR —Hydroscience & Engineering researcher Chris Jones says that clues to the reduction in nitrate levels can be found in the differences between corn and soybean  growth, soil chemistry, and the decay of other crop residues. Conversely, the dead and decomposing soybean plants can increase the amount of nitrate in the soil vulnerable to loss.

“We know we can’t just focus on fertilization of corn. We need a systems approach to improve water quality. It also demonstrates the power of monitoring water quality. Without this data, we could easily have missed this important and counter-intuitive conclusion.” 

As a result, Jones says he believes that declining amount of soybeans planted may have reduced the cropped areas most susceptible to nitrate loss, more than compensating for the increased fertilizer inputs on corn production.

 

Study links contaminants from rural well water to birth defects


(Darin/Flickr)
(Darin/Flickr)
Nick Fetty | May 4, 2016

Water contaminants found in some rural agricultural areas could be linked to birth defects in pregnant women, according to a recent study co-authored by a University of Iowa researcher.

Peter Weyer, associate director of the Center for Health Effects of Environmental Contamination at the UI, along with Jean Brender, professor emeritus at the Texas A&M School of Public Health, studied water sources for pregnant women in rural areas of Iowa and Texas. The researchers found the presence of atrazine, nitrate and arsenic in well water samples.

Nitrate, commonly used in fertilizer, has been linked to neural tube defects, oral clefts, and limb deficiencies while atrazine, also used in fertilizer, can cause abdominal defects and gastroschisis. Arsenic contamination was found to be more of an issue in Texas where it seeps into water sources through the bedrock and if consumed by pregnant women can cause developmental problems in fetuses. While each of these compounds individually have been tied to birth defects and other health complications, the effects are unclear when two or more of these compounds are found in a single water source.

This recent study builds on work published by Weyer and Brender in 2013. Their 2013 study looked specifically at nitrate pollution in water and its links to birth defects. The researchers studied water sources for pregnant women in Iowa and Texas and used data from the National Birth Defects Prevention Study.

In both studies, the researchers recommend that before becoming pregnant, women should have wells tested for contaminants. If contaminants are found in a well women should consider other sources such as bottled water.

 

Nitrates often released back into rivers


Photo via Jason Mrachina; Flickr
Des Moines cityscape. Photo via Jason Mrachina; Flickr

According to the Des Moines Register, Des Moines’ nitrate removal facility was responsible for dumping approximately 13,500 pounds of the contaminant into the Raccoon River last year.

Nitrates can be detrimental to human health if consumed in high enough quantities, which is why the U.S. Environmental Protection Agency requires drinking water to be monitored for the compound. However, once nitrates are removed from the drinking water, they are often released back into Iowa’s waterways.

The Des Moines location is not alone in this practice. The majority of Iowa’s other 15 nitrate removal facilities follow the same routine, and many do not monitor what quantity of nitrate they are releasing.

Although this practice is completely legal, it has serious environmental ramifications. The Raccoon River is part of the Mississippi River watershed, which empties into the Gulf of Mexico. Midwest fertilizer runoff from the watershed, high in nitrates, is largely responsible for the Gulf of Mexico’s Dead Zone. Nitrate levels in the Gulf’s water allow algal blooms to thrive, which in turn leads to low oxygen levels that are deadly for many aquatic species.

The future is not completely bleak; progress is being made towards preventing the nitrates from reaching water systems in the first place. Farmers and researchers are collaborating to explore and advance environmentally sustainable agricultural practices.

On the Radio: Des Moines Water Works Safety Measures


Photo by w4nd3rl0st (InspiredinDesMoines); Flickr

This week’s On the Radio segment covers Des Moines’ actions in meeting the high nitrate levels in their river water. Continue reading for the transcript,  or listen to the audio here: Continue reading

Advocates urge safer and cleaner drinking water in Iowa


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Photo by instory_fan; Flickr

A campaign for cleaner water took place in Des Moines on Tuesday urging the state to take  mandated actions to reduce water pollution in some Iowa rivers with high nitrate levels. Continue reading