Just one more delicate balance destroyed by Roundup. Toxic algae gets bloom booster applications in Lake Erie from Roundup Ready crops. The glyphosate applications create 20-25% of the lake’s phosphorous pollution. The problem? Mobilization of dissolved reactive phosphorous (DRP) draining into the Maumee watershed. Cynobacteria find glyphosate itself highly nutritious. It’s reached epic proportions in recent years.
Pinpointing the problem is a result of research done by Christopher Spiese, chemistry professor at Ohio Northern University, and Roundup herbicide is responsible for the huge increase. As we learned in the summer issue of Garden Culture Magazine, soil type and pH can both cause undesirable things to happen with glyphosate. Like mobilizing in Napa Valley vineyards, and hard water making Roundup’s acids come apart – because of soil, pH, and minerals naturally present.
Spiese was surprised to discover that soil pH and mineral content all had a direct affect on Roundup’s behavior, and it’s affect on the phosphorous in the upper 2 inches of field soils.
“The P in glyphosate is what we call phosphonate, a phosphorus-carbon bond,” he explains. “A phosphorus-carbon bond is extraordinarily stable. It’s very difficult to break. We don’t expect this to contribute one bit to the DRP.” (Spiese quote from No-Till Farmer)
But it is. He’s not the first soil scientist to consider the Roundup – toxic algae connection. A study conducted in 2008 under the Ohio Sea Grant also suspected that Roundup was contributing to the resurgence of Cyanobacterial bloom in Lake Erie, though nothing concrete developed. Suspicion isn’t hard to arrive at, because the phosphorous issue in Lake Erie was conquered in the 80s. Suddenly it returned about 15 years later, growing stronger year by year. A phenomenon that matched the birth of Roundup Ready crops, and the ever-increasing field occupation. The majority of farms in the Maumee Basin grow Roundup-tolerant corn and soybeans, the total acreage of which has exploded in recent years.
As with any area, the soil type isn’t the same all over the Maumee watershed. Spiese discovered that the amount of desorption glyphosate caused wildly varied from 1% to 100% in some hot spots. And this is on top of the DRP desorption scientists have already known about and reported in various situations as early as 1998. There is significant loss of P from cropland. Not just from surface runoff, but also in freely draining sandy soils, and field drain tiling. Environmental scientist John Freeland of the American Geophysical Union cites several of them in his addition to this development of a Roundup – toxic algae bloom discovery:
“A subsurface mechanism for phosphate transport is now well documented. Any conditions in the soil that would make phosphorus more mobile, such as a chemical that would loosen soil’s tight grip on phosphorus, would set up a situation for off-site losses of phosphorus. The Spiese study presents evidence that glyphosate does just that in some, but not all soils.” — John Freeland
The Maumee River is a major waterway. It’s the largest river in the Great Lakes System. The watershed channels the drainage off of over 4 million acres into Lake Erie. It covers 6,562 square miles of land in Ohio, Indiana, and Michigan that is largely productive farmland… thanks to 16,000 miles of drainage ditches, and heaven knows how many miles of underground drain tiles. All of which transport water, nutrients, and pesticides not tied up by soil and plants into the Maumee River – the largest conduit of phosphorus pollution flowing into Lake Erie. Farmers apply some 2.2 million pounds of Roundup to these fields annually. Spiese has determined that 1/3 pound of glyphosate per acre mobilizes as DRP, and winds up in the lake.
No-till farming is also part of the equation. This does greatly lessen topsoil loss, and the amount of sediment that winds up in waterways and lakes. However, it leaves phosphate buildup in the top 2 inches of soil where it readily mobilizes. No-till also greatly increases the amount of water exiting fields through enlarged soil tunnels into the tiling below. No surface runoff necessary for it’s mobilization.
It’s not just happening in western Lake Erie.
Some of the richest farmland in North America sits in the watersheds that feed the Great Lakes. Both in the US and Canada. Ontario farmland also has problems with DRP runoff, but that’s not where this algal bloom is coming from. It’s not coming out of Detroit either. The major source is the mouth of the Maumee River. There are also problem spots in Lake Ontario, and Lake Huron, but nothing like the epidemic taking place in Lake Erie.
The Saginaw Bay in Lake Huron, where the Saginaw Valley Watershed drains into the lake has the second largest Cyanobacterial bloom problem. The watershed handles drainage out of a big portion of mid-Michigan’s farmland, where not just Roundup Ready corn and soybeans flourish, but Roundup Ready sugar beets as well, especially in The Thumb area.
The Lake Huron bloom looks unimpressive compared to what’s happening in Ohio. However, it’s not difficult to see the similarities in land use between the two on this NASA satellite image, along with the algal blooms. Google Earth is even better for a closer look for farmland concentration in both Saginaw Valley and Maumee Basin watersheds. Notice that the expanse of uninterrupted farmland in Michigan emptying into Saginaw Bay covers only about 1/4 of the peninsula. Forest covers much of what lies north if the Bay Area. Part of the farmland to the south lies in the Maumee watershed. The west side of the state drains into Lake Michigan, where the only algae issues is in a northern Wisconsin bay. Compared to the massive expanse of the Maumee watershed!
So, there is far less free phospherous and phosphonate dumping into Saginaw Bay than out of the river at Toledo. Amounts of Roundup applied per acre won’t vary much, though soil composition may differ some from that in Ohio. It will still be a contributor to the problem in Saginaw Bay. It may be that there are more buffer zones in use in Michigan versus Ohio. Maybe there’s greater crop diversity. Maybe open water currents keep the cyanobacterial bloom contained. Will they take a deeper look with the establishment of a direct connection to Roundup Ready crops, and no-till farming?
“Farming in the heart of one of the world’s largest fresh water reserves must not be taken lightly. Special management and practices will need to be continually implemented to minimize P leaving agriculture land. Let there be no misunderstanding producers will come under more scrutiny in the future when it comes to nutrient management, particularly with phosphorus. Small management changes implemented on more than one million acres surrounding the Saginaw Bay can have a large total impact.” — Steven Poindexter, Michigan State University
Reducing the amount of glyphosate applied per acre to say, zero pounds? Probably not what he’s referring to as small changes. But the stuff is like a free radical. It turns problems into mega issues: super weeds, super algae, super secret food ingredients. What’s next?
- Source: No-Till Farmer
- American Geophysical Union
- Ohio Sea Grant Looks at Roundup
- Tiling Phosphorous Loss
- Vintage Glyphosate – US/CA 10, page 35
- Saginaw Bay – Michigan State University
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