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9 Things You Need to Know About Water Quality
Water quality — or lack of it — is the buzzword in environmental and agricultural circles these days. Here are nine points to keep in mind about the issue following a panel discussion at the recently held North American Agricultural Journalists meeting in Washington, D.C.
1. Agricultural fertilizer is the largest contributor to nitrate levels in the Gulf of Mexico. When combined, though, other causes contribute more nitrates.
Bill Wilber, chief of the National Water Quality Assessment Program for the United States Geological Survey (USGS), cited USGS data from 2002 that showed farm fertilizer contributed 41% of nitrogen (N) to the Gulf of Mexico from the Mississippi River Basin. Even if all farm fertilizer was eliminated, though, other sources also contribute the following:
* Atmospheric deposition: 26%
* Manure (confined): 10%
* Fixation and other legume sources: 9%
* Wastewater treatment/facilities: 7%
* Urban areas: 7%
2. Nitrate loads into the Gulf of Mexico from the Mississippi River Basin rose 14% from 1980 to 2010. Loading hasn’t been uniform, though, among various river basins emptying into the Mississippi River Basin.
Nitrate loading in the Illinois River Basin declined 15% in that 30-year period. However, Wilber notes USGS scientists cannot adequately explain this and, if improved, on-farm fertility management is the reason.
3. It’s not just surface runoff that may be increasing river nitrate levels. “Groundwater may also be an increasing source of nitrates to the Mississippi River Basin,” says Wilber.
Wilber says that since the mid-1990s, nitrate concentrations have risen during low stream flows at the Mississippi River. Nitrates in groundwater may keying this, says Wilber.
Due to slow nitrogen movement through groundwater, recent stream quality changes may reflect land management from many years ago. For the same reason, the full effect of current management practices may not be measurable in rivers until many years in the future, he says.
4. Conservation practices can be antagonistic when it comes to nutrient management. “If you apply one conservation practice, it can accentuate the loss of other nutrients,” says Don Parrish, senior director, regulatory relations for the American Farm Bureau. “Nitrogen and phosphorus (P) move through the landscape totally differently. “Phosphorus moves over the soil, nitrogen moves through the soil.”
5. The growing season isn’t when most nutrients are lost. “Most nutrient losses occur from November through May,” says Parrish.
That’s the time when there’s little plant growth occurring. Little plant root means little uptake of nutrients. If nutrients are present, precipitation can cause it to move downward in the soil and exit fields via tile lines.
Cover crops are one way to salvage nutrients, although it takes more management to implement them, he says.
6. Conservation practices may not be enough if crop rotations do not change. That’s according to Craig Cox, senior vice president for agriculture and natural resources for the Environmental Working Group. “Even if producers become increasingly efficient, say if they lost just 5% of fertilizer applied, multiplied over millions of acres (an estimated combined 173.8 million acres for 2015 for corn and soybeans), that still is a significant nutrient load,” he says.
7. Regulation may be inevitable . . .
"It may not be a question of if agriculture should be regulated, but how agriculture should be regulated,” says Cox. “My answer is we need a basic standard core set of conservation practices that landowners have in place.”
After talking to farmers and scientists, here’s a set Cox would like to see:
* Buffers between cropland and waterways.
* Grass waterways.
* Management practices to reduce the impact of cattle and other livestock on stream quality.
* No manure application on frozen or saturated ground.
8. . . . but mandatory standards have problems.
“If buffers are not managed right, they may cause more problems than solutions,” says Parrish. “So just be careful about how you mandate things on the landscape.”
A better way may be what’s going on in Ohio and P-spurred algae blooms in Lake Erie, he says. Ohio farmers are enrolling in continuing education and becoming certified to apply fertilizer. “Education is knowledge and power,” he says.
9. There’s good news in all this, though. From 1980 to 2014, U.S. corn production rose nearly 115%. “That’s been done with 4% less nutrients,” says Parrish. “That is a huge gain in efficiency.”