Experts Dispute Study That Relates No-Till to Algae Problem

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Phosphorus runoff contributes to the shoreline of Lake Erie accumulating algae.

 

Photo courtesy of EPA

 
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Experts Dispute Study That Relates No-Till to Algae Problem

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Rachel Doctor

Last spring, a study conducted by Hiedelberg College's water lab in Tiffin, Ohio, reported that no-till farming was contributing to the dissolved phosphorus that enters the water supply and causes an accumulation of algae in Lake Erie.

According to Norm Widman, national agronomist with the Natural Resources Conservation Service (NRCS), no-till systems are not the reason for this dissolved phosphorus, but several things have caused a “perfect storm” for this phosphorus runoff.

”Most phosphorus runoff is caused by the timing and methods of application of phosphorus,” Widman says. “Too much application in the summer and fall with no incorporation leaves extra phosphorus to be sitting on the soil surface that can be dissolved into the water supply and eventually make its way to Lake Erie.”

In an article in The Toledo Blade, one of the Great Lakes region's top algae researchers, The Ohio State University's David Culver, says he can't say farming is to blame for any of the algae problems he's seen, nor can he rule out any other potential sources of pollution, especially sewer contamination.

In fact, the conservation practices of no-till and high-residue mulching improve soil tilth and reduce runoff and erosion, as do other practices such as cover crops and buffers. Several other things farmers can do to decrease the amounts of soluble reactive phosphorus (SRP) in the water supply are listed below. The bottom line is that there is no correlation between no-till farming and increased phosphorus runoff.

To read the full article from The Toledo Blade, visit: toledoblade.com/apps/pbcs.dll/article?AID=/20080907/COLUMNIST42/809070333

For more information about conservation tillage, visit CTIC's web site: www.conservationinformation.org/?action=learningcenter_core4_convotill

For any additional questions, contact Norm Widman at norm.widman@wdc.usda.gov or 202-720-3783.

Potential practices and management to address increased soluble reactive phosphorus:
 
  1. Use continuous no-till cropping and high-residue mulch till systems to improve soil tilth and reduce runoff and erosion.
  2. Use cover crops to take up nutrients from summer and fall applications of manure and fertilizers, reduce erosion and runoff.
  3. Incorporate more of the nutrients.
  4. Do not apply nutrients from any source during the winter season, unless fully incorporated.
  5. Implement soil tests on all cropland fields and follow agronomic application recommendations.
  6. Implement precision farming technologies to better match nutrients needs with soil, crop needs, and crop response.
  7. Implement buffers within the fields to better filter runoff and remove filter strip biomass every 2-3 years.
  8. Implement practices to not only address the existing soil compaction problems, but also implement practices that will minimize future soil compaction.
  9. Develop a National Phosphorus Assessment Tool that will better assist states to develop management systems to address phosphorus runoff.

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