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No-till pollution claims hard to understand

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• UCS casts aspersions on a practice that allows some farmers to improve soil conservation. • UCS folk have no clear understanding of how conservation tillage works. • Plowing to kill weeds is not part of most reduced-tillage systems.

As if the Environmental Working Group (EWG) isn’t challenge enough to farmers doing their best to provide adequate food and fiber to a rapidly increasing global population—while also doing their best to preserve the natural resources necessary to accomplish those goals—along comes another self-righteous organization to cast aspersions on a practice that allows some farmers to improve soil conservation.

The Union of Concerned Scientists (UCS) is taking no-till to task, claiming that the practice is linked to increased waterway pollution. A recent news release hit my e-mail box with that claim.

The “news” item—and I use that term “news” guardedly—suggests that “conservation tillage, turning or plowing the soil to kill weeds, may be linked to an increase in toxic algae blooms.”

The opinion piece—which is a more apt description—says the claim is based on “new research.” The toxic blooms come from runoff that carries phosphorus into waterways, according to the UCS.

Apparently, the UCS folk have no clear understanding of how conservation tillage works. The process of “turning or plowing the soil to kill weeds,” does not fit the definition of most conservation tillage practices and particularly not no-till, which minimizes soil disruption to seedbed preparation. Other practices, including reduced-till, ridge-till and other systems, vary in the amount of soil disruption used to plant seed. But plowing to kill weeds is not part of most reduced-tillage systems.

But no worries, the UCS offers options. “Sustainable practices, like cover crops, achieve all the suggested benefits of no-till and more, but the agriculture industry continues to push no-till,” according to a UCS spokesperson. They add: “Unlike sustainable practices, no-till depends on expensive purchased products. It’s good for the industry’s bottom line, not so good for the rest of us.”

I don’t disagree with the idea of using cover crops. Indeed, many practitioners of no-till, reduced-till and minimum-till rely on cover crops to provide the residue they need to hold moisture, increase organic matter in the soil and protect the land from water and wind erosion in the off-season.

Some also plant into small grain stubble and residue from a previous crop—which also helps prevent erosion through fall and winter months.

Some no-till farmers I’ve interviewed over the years also plant cover crops following fall harvest for the express purpose of holding soil over the winter and supplying residue at planting. Those cover crops also build organic matter and the root systems help move water deeper into the soil, stockpiling it for the next crop.

It’s not always feasible, however. Cover crops, like the plants that will follow them, require moisture. Apparently, UCS folk have never spent a winter in the Southern High Plains, where the wind blows strong and rainfall is uncertain. Even with irrigation, the challenge of maintaining a cover crop throughout the winter may require more water than can be depended on or justified. Conserving water is also part of a sustainable system. Water demand for a cover crop must be balanced against the potential advantages. Sometimes it works out; sometimes not.

We’ve written many articles depicting the various ways farmers use reduced tillage practices, including cover crops, to improve soil conservation efforts, preserve water and prevent runoff. We’ve applauded efforts of those who found ways to improve stewardship—sustainability—while maintaining profitable yields. And still we have self-righteous organizations that hijack the term “sustainability” and define it in their own narrow terms. To be sustainable, a practice has to make sense. In some cases, cover crops fit that criterion. In some they do not.

Farming is not a one-size-fits-all proposition. Creativity and flexibility are part and parcel of any successful agriculture enterprise and trying to fit all operations into one pigeon hole is doomed to failure.

 

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Discuss this Blog Entry 1

Doug Gurian-Sherman (not verified)
on May 6, 2013

Ron,

You misrepresented my description of tillage.

You wrote that my blog post as says that conservation tillage or no-till are used to control weeds, and so on. In fact, the description of tillage was just that, a description of the uses of plowing. It was not a description of no-till or con till. It was in a separate paragraph from the discussion about no-till, and was intended to give readers a little background about what tillage is, since many of them do not know about farming practices.

Since you do not link my blog, I supply that link here, and encourage readers to see for themselves: http://blog.ucsusa.org/toxic-algae-and-no-till-117

Groups like EWG and UCS want farmers to succeed. We also want farming to not only be productive--which it has been, to the credit of farmers and ag scientists--but good for the environment, farm families, farm workers, and rural communities. To accomplish that, we need policies that allow farmers to adopt more sustainable practices.

There are possible solutions to some of the problems that no-till may be causing, as my blog notes. These may include some forms of conservation tillage that do not leave so much phosphorus at the soil surface. So far, though, there is not enough information to know if that will work.

As for cover crops, they could undoubtedly be used effectively and economically much more than they are used in the corn belt now. Only a very small percentage of growers use cover crops now. There are several reasons for this, and these need to be addressed.

The issue of cover crops potentially drying soils is well known (some of that could have been useful this year!). Research out of U. Nebraska suggests that there may be some viable solutions to this problem. In addition, for states in the central corn belt, where rainfall is usually adequate, this is not an issue most years.

On the other side of the ledger, because cover crops help build soil organic matter over time, and because soils with more organic matter and good structure hold more water, cover crops can improve drought resistance over time. But it takes years to achieve this, so there can be some possible short term trade-offs, which are hard to accept.

So yes, a one-size-fits-all approach will not work. But we do not suggest that is the way to go.

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