Nationwide, farmers are getting more grain out of their fertilizer, according to the National Corn Growers Association. Nitrogen use has decreased 38 percent in terms of pounds per bushel of corn, said Rod Snyder, director of public policy for the trade group.
Nevertheless, corn farmers are using as much fertilizer per acre as ever on their high-yielding crops, according to federal data. On average, farmers applied 58 pounds of nitrogen per acre to corn crops in 1964. By 1985, that number had grown to 140 pounds per acre, where it remained in 2010.
In addition, more acreage is being planted as corn prices boom, according to U.S. Department of Agriculture data. In 2012, farmers planted 96 million acres of corn – the highest level in nearly 70 years, and up nearly 22 percent from a decade earlier.
“The primary cause [of nitrate pollution] is row crop agriculture, and the primary culprit of that is corn. That’s being exacerbated by the fact that corn is expensive right now. People are taking areas out of conservation and putting them into corn production,” said Matt Rota, science and water policy director for the New Orleans-based Gulf Restoration Network.
Farmers use many methods to reduce runoff: planting cover crops, adjusting the amount of fertilizer and when it’s applied. Such conservation practices in the Upper Mississippi River basin reduce nitrogen loss by an average of 18 percent per acre, according to a USDA report.
But the same report found that only 14 percent of cropland consistently had good nitrogen management.
“What we are showing is how bad the problem would be if there were no conservation,” said Lee Norfleet, a USDA soil scientist. “If there is an uptick, it would be a lot worse if a lot of (conservation) practices had not occurred.
In addition, Norfleet said, it takes time for farmers to adapt to the changing genetics of corn, which needs less nitrogen now. Farmers who don’t adjust could end up over-applying nitrogen at the rate of 23 pounds per acre.
Other sources of nitrate also may have increased.
The Missouri River basin, which includes the cities of Denver, Omaha and Kansas City, grew by more than 1.3 million people between 1990 and 2000, now reaching more than 11 million people.
In addition to crops, “there’s also animal feeding operations, sewage treatment plants. Petrochemical industries discharge into water. And then urban runoff,” Rota said.
Home use of fertilizer for yards and gardens nearly doubled between 1987 and 1997, although it was just 1 percent of the total nitrogen, according to the USGS nationwide study. Nitrogen from manure increased almost 5 percent and nitrogen from the atmosphere, largely from the burning of fossil fuels, increased 13 percent.
Reliable data on another urban source of nitrate, sewage treatment plants, are not available. And while septic systems are responsible for about 12 percent of the nitrate in the Missouri River watershed, there is no data on whether it has increased.
None of this information provides definitive answers about what is driving the increased contamination of the river. Nitrogen applied to the ground may never reach the Gulf, depending on weather patterns, vegetation, waterway conditions and many other factors.
“There isn’t clear evidence to support the hypothesis that it’s ag or urban or wastewater treatment plants,” Sprague said. “We don’t have a good understanding of how these things have changed over time.”
A foot soldier in the war
The Missouri River has been monitored at Hermann since 1844, which makes it a good place to observe changes in the river.
See what we're tweeting about
8 Comments
Add CommentWhat is needed to get a clearer picture of the problem and its sources is to be able to deploy a large number of remote sensing devices that can monitor the water at many locations without having to send samples to a lab. This would give a better indication as to the principle entry points of the nitrates into the rivers and allow a more responsive methodology for characterizing and controlling the situation.
Reply | Report Abuse | Link to thisAs more data is collected, additional sensors can be deployed to narrow the search for the sources. Once sources are identified, they can controlled using either a nitrate tax to make it too expensive to continue allowing nitrates to enter the system or some other sort of incentive to fix the problem locally.
I am sure that there is room for research in ways to break the nitrates down before they reach the gulf as well. Perhaps systems located at the various dams along the way to process the water as it goes through. It would have to be pretty massive to be able to treat the volumes of water flowing through but perhaps it could be distributed more easily along the streams flowing into the rivers instead.
We do live in a world where everything is interconnected and where the miracle cure for one can be the eternal curse for another. We need to remember that we all need to share this planet and live more harmoniously with it.
I can't believe our rivers and the Gulf are being polluted by those evil, rotten, money-mongering oil companies...oh...wait...I mean, farmers.
Reply | Report Abuse | Link to thisThe world is becoming scarier than ever.
Reply | Report Abuse | Link to thisLittle progress is being made because global resources are being diverted combating a non-pollutant (CO2). The real significant pollutants are losing out of the trillions invested globally, with no resultant effect.
Reply | Report Abuse | Link to thisWe need to re-focus our attention (and money) to real solvable pollution problems. GK
"Little progress is being made because global resources are being diverted combating a non-pollutant (CO2)."
Reply | Report Abuse | Link to thisDenial is a mental disease far more debilitating then liberalism. In the end it results in a terminal disease.
Nitrogen increases cause phytoplankton to multiply, but this should increase nutrients for species in the food chain that consume the plankton. As the dead zone grows, so should the abundance of sea food as the oxygen further out returns to the balance nature established. This is not the case as evidenced by increasingly smaller catches in the gulf. Unfortunately there is other pollutants at work that are destroying the food chain farther out. Pesticides (which are made from petrochemicals) and crude oil which has been purposely sunk to the floor of the gulf (does anyone remember or care who NALCO was or how much they spent on lobbying during the worlds worst oil spill?)is suddenly and suspiciously not investigated or even suspect according to this article. The excuse is just that scientists don't understand it all. Apparently no one is getting paid enough to put the blame where it belongs. It is far more convenient to blame individuals that fertilize their lawns and farmers growing corn for ethanol.
Everything has a cause and effect and it should be a no-brainer to look at the total picture, but Americans have been so dumbed down by the mainstream media which is funded by big business (not liberal environmentalists as claimed by those responsible) that the obvious now becomes the ridiculous as evidenced by G. Karst's post above.
CO2 is as much a part of the problem as the rest of the oil and coal industry's pollutants. CO2 increases the acidity of the water and raises the water temperature which both benefit algae and ultimately plankton production and destroys coral which lives on live plankton, not dead decaying plankton and the poisonous bacteria it creates.
It is hardly a misunderstood problem. It is just another case of active denial by the very people and industries that are creating the problem in the first place.
What humans need to do is weigh the beneficial and non-beneficial attributes and choose solutions based on logic not greed.
Nitrogen fertilizer is depleting oxygen the dead zone of the Gulf. Why not pump air to the bottom of the gulf like is done in fish tanks? Why not pay for the operation by a tax on nitrogen fertilizer? Let the polluters pay for the consequences of their pollution.
Reply | Report Abuse | Link to thisIn my opinion, the hidden factor here is depletion of the soil in terms of buried carbon. i.e the nitrogen is not being retained as well by the soil because it is becoming more and more just a 'dry hydroponics' sterile medium.
Reply | Report Abuse | Link to thisWe need to make better soil by getting away from the idea that agriculture is about adding nutrients to a dead inorganic media designed only to stabilize the root system.
Move towards ways of allowing more nutrients from fertilizer to be retained, such as biochar, burying stalks, low tillage, etc. Maybe even letting fields lie fallow and alternating to give bacterial and worms time to establish themselves between crops. Investigate multiple crops in the same field (I know it makes harvesting more complicated but nutrients may be taken up faster. We need to develop actual soil as it is MUCH more resistant to losing nutrients than the basic minerals.
Looking over the responses, I despair of the public seeing agriculture as a biological process. They seem to regard it as an industrial one.
Of course doing the common sense thing and completely eliminating the levees south of New Orleans is just not considered of course.
Reply | Report Abuse | Link to thisIf this was done the waters of the Mississippi would then be filtered by the remaining marshlands that CAN utilize those excess nutrients and regrow themselves.
Destruction of these levees doesn't have to entail destroying communities if done right, but like I said since it's not even considered as an option proper planning has never been done. How pathetic.