Crop Rotation Generates Profits without Pollution (or, What Agribusiness Doesn’t Want You to Know)

, senior analyst, Food and Environment | October 11, 2012, 12:56 pm EDT
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UPDATE: March 18, 2013, 3:15 pm: See bottom of post for an update on coverage of this story.

Big Ag has worked hard for decades to instill a belief—in farmers, policymakers, and the public—that its chemical-intensive industrial farming methods are more productive than low-input methods, and more profitable for farmers. In recent years, study after study has cast doubt on this view, and now a team of government and university researchers has published perhaps the most compelling data yet showing that more sustainable farming systems can achieve similar or greater yields and profits, despite steep reductions in chemical inputs.

The so-called Marsden Farm study is a large-scale, long-term experiment conducted by researchers from the U.S. Department of Agriculture (USDA), the University of Minnesota, and Iowa State University. So no, these aren’t California hippies or east coast elites. These folks know the dominant agricultural landscape of the Midwest—corn and soybeans. But they also want to better understand how systems that incorporate other crops, and even livestock, compare when performing head-to-head.

Keeping it simple (or not)

Over a period of nine years (2003-2011) on the Marsden Farm at Iowa State, the researchers replicated the conventional Midwestern farming system—a highly simplified rotation of corn and soybeans on the same fields on a two-year cycle, with copious additions of chemical fertilizers and herbicides. Alongside it, they grew two multi-crop alternatives: a 3-year rotation incorporating another grain (triticale or oats) plus a red clover cover crop, and a 4-year rotation that added alfalfa (a key livestock feed) into the mix.

Aerial view of the Marsden Farm plots. (m=corn/maize, s=soybeans, g=small grain, a=alfalfa)

The researchers compared these systems on productivity, profitability, and environmental health, and their findings, published this week in the journal PLOS One, are striking. In particular:

  • The more complex systems enhanced yields and profits. Over the course of the experiment, average corn yields were 4 percent higher, and average soybean yields 9 percent higher, in the longer rotations compared to the conventional system. Furthermore, the researchers found that the longer rotations were just as profitable as corn-soy alone.
  • Conventional corn-soy rotations require more chemical fertilizer and energy inputs. Fertilizer use was higher in the 2-year rotation than in the more complex systems. And this difference increased over the course of the experiment, with the 3- and 4-year rotations requiring even less of these inputs in the later years, probably due to cumulative improvements in soil quality over time.
  • Diversification controls weeds while slashing herbicide applications. The longer rotations reduced herbicide use by a whopping 88 percent compared with the conventional system, with little difference in weediness. Furthermore, the ecotoxicity of the systems (as measured by the freshwater toxicity of the herbicides used) was 200 times less in the longer rotations. Given everything we know about weed resistance and rising herbicide use on U.S. farms (including this new estimate), strategies that help farmers control weeds with less herbicide are critically needed.
  • Longer rotations substitute labor for other inputs. Some people will no doubt see this as a strike against crop diversification. But with energy costs on the rise and unemployment stuck just under 8 percent, that’s starting to seem like seriously fuzzy logic.

Improving farming…when the cows come home?

In addition to incorporating more crops, the longer rotations at the Marsden Farm also brought animals back into the mix. The authors note that:

Reintegration of crop and livestock production, as represented by the forage legumes and manure applications present in the more diverse systems, is not simply another aspect of cropping system diversification. Instead, it embodies an important principle in sustainable agriculture: system boundaries should be drawn to minimize externalities.

In other words, livestock will produce manure wherever they are raised. In a CAFO, manure is likely to become a waste product and water pollutant. But if, as in the longer Marsden rotations, feed grains and alfalfa are grown for livestock raised on-site or nearby, their manure in turn becomes an asset, fertilizing the crops, improving soil quality, and reducing the fossil fuel needed to transport grain and manufacture synthetic fertilizers.

The researchers conclude:

Substantial improvements in the environmental sustainability of agriculture are achievable now, without sacrificing food production or farmer livelihoods. When agrichemical inputs are completely eliminated, yield gaps may exist between conventional and alternative systems. However, such yield gaps may be overcome through the strategic application of very low inputs of agrichemicals in the context of more diverse cropping systems. Although maize is grown less frequently in the 3-yr and 4-yr rotations than in the 2-yr rotation, this will not compromise the ability of such systems to contribute to the global food supply, given the relatively low contribution of maize and soybean production to direct human consumption and the ability of livestock to consume small grains and forages. Through a balanced portfolio approach to agricultural sustainability, cropping system performance can be optimized in multiple dimensions, including food and biomass production, profit, energy use, pest management, and environmental impacts.

Corporate interest vs. public good

Now, you can bet that Monsanto (or Syngenta, or Cargill) would never pursue a study like this one. I mean, why would they? There’s very little for big corporations to sell to farmers who are engaged in low-input agriculture. In fact, just the opposite—the more farmers are convinced they can’t be profitable without pricey inputs, the better the companies’ bottom lines will look.

Even when it just isn’t true.

And that brings me to another interesting finding out of the USDA last month. A trio of researchers at the agency’s Economic Research Service (ERS) documented the extent to which private companies hold the reins when it comes to research on food and agriculture. According to the ERS brief, the private sector performs 53 percent of total food and ag research in the U.S. And the long-term trend has been toward greater corporate-funded R&D.

Of course, it’s only natural that companies would invest in areas that pay off in private return rather than broader social good. That’s what corporations do. They also—as you would expect—lobby for policies that serve to increase those purely private returns on their research dollars.

But the ERS economists go on to cheerlead public research as “complementary” to all this private sector R&D. Whereas I would argue that current levels of public investment are inadequate—pitifully small, really—to address the enormous agricultural challenges our society faces, which the private sector has no interest or incentive to deal with.

Every now and then we get a Marsden study that refutes Big Ag’s dominant storyline. But mostly farmers and policymakers just hear what the companies want them to hear.

So when the Marsden researchers say in their groundbreaking paper that  “there has been an interest in reintegrating crop and livestock systems as a strategy for reducing reliance on fossil fuels, minimizing the use of increasingly expensive fertilizers, and limiting water pollution by nutrients, pathogens, and antibiotics,” it’s important to remember who has that interest.

And who doesn’t.

UPDATE: March 18, 2013, 3:15 pm:

Since I wrote this post last fall, the story of Iowa State University’s Marsden Farm study has been covered by the New York TimesWired magazine, Iowa Public Radio, and farm press outlets such as this one, and shared widely on social media, as with this tweet:


As a result of all this publicity, I am told the peer-reviewed article—published by the open-access journal PLOS ONE—has been viewed or downloaded more than 21,300 times.

(To put that in perspective, according to this usage table, PLOS ONE published 5,250 research articles on a variety of scientific topics in 2012, and their average lifetime usage—combined page views and downloads—was just 900.)

So it is curious that Iowa State’s Office of University Relations, which handles communications for the university and typically (and appropriately) takes every opportunity to trumpet the knowledge, successes, and contributions of its researchers to the general public, hasn’t done more to shine a light on these groundbreaking findings. Yes, there’s a pretty wonky article about it buried in the university’s ag extension bulletin. But as a premier taxpayer-funded university in the Midwest, ISU has a responsibility to use the tools at its disposal—a press office that can reach mainstream media, along with the university’s Twitter feed and Facebook page—to tell the average person in farm country and beyond about this research and how it could revolutionize farming.

Why wouldn’t they do that?


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  • Jim Nelson

    Doesn’t anyone but me object to dim gray text? The above exchanges look very interesting, based on the first few words I can read before an eyestrain headache begins. If you agree with me in wondering what was wrong with black on white (which has worked pretty well for the last thousand years of paper printing), please join me in asking UCS to use it for this blog.

  • Klay

    Sustainable permaculture like the Geoff Lawton way! Nice article.

  • This fits with everything we have been seeing at Sustainable Harvest International over the last 15 years as we have helped farmers in Central America diversify their farms. It drives me crazy that funders still focus on chemicals to increase production, especially where unemployment is super high.

  • The Marsden Farm Study is an important step in the right direction. I cite the example of Polyface Farm in the Virginia Shenandoah Valley reported in Michael Pollan’s “The Omnivore’s Dilemma” Part II “Pastoral Grass.” Pollan’s description of the Polyface Farm methods, called “Beyond Organic,” are far in advance of those at Marsden Farm. However, Polyface Farm is not part of a formal study other than by its owner, which is why Marsden is important and a logical move in the direction of the Beyond Organic methods used at Polyface Farm.

  • Juan Colombo

    The case for adding livestock to the rotation is much in debate where I work (a mixed agribusiness in Uruguay with crops and livestock side by side), both from a cost point of view as much as a land health one.
    Cattle stepping on farm land indeed produce the benefits of an additional rotation, natural manure deposits that act as fertilizer, as well as providing valuable feed for our livestock.
    But cattle stepping on carefully kept land for no-till farming more than offsets the benefits, we have found. Cattle weight compresses the fragile top soil, affects oxigenation and also makes it difficult to plant seeds on compact soil afterwards (no-till farming requires that top soil is “tender”).
    Cattle pasturing on farmland has made it necessary to “till” and then level the land before returning it to crops. Two separate tractor intensive activities. Tilling releases valued nitrogen to the air, and goes against farming best practices. It also adds cost to the pocket and tothe environment of increased fuel consumption, additional labor, and time to do the job.
    Additionally, the returns on farming far exceed those of ranching. We conclude that no acre of land suitable for farming should ever be used to ranching.
    We are opting instead to dedicate one rotation to cattle feed crops: sorgum, black oats, and the like, which provide an additional rotation without the drawbacks of having cattle actually stepping on the farm.
    We would very much appreciate any opinion, idea or research to validate or challenge our assumption.

    • Juan, thanks for reading. I think the Marsden authors are proposing essentially the same solution you are pursuing. Not cattle grazing on the
      crop fields, per se (though there are some schemes in which livestock graze on crop stubble), but rather livestock grazing in close proximity to those crop fields.

      Michael Russelle ( and Alan Franzluebbers ( are two scientists at the U.S. Department of Agriculture who are working on such integrated systems. They have a recent book chapter titled “Opportunities and challenges for integrating North American crop and livestock systems” ( that might be of use to you.

      Best to you in your work in Uruguay!

    • If you are trying to graze cattle on cover crops and crop residue I can see the problems you discuss.

      In our program we plant perennial pasture that is meant to be around for 5 years or more and then rotate into annual crops. One thing to consider is that cattle shouldn’t be on land until the pasture is about 1 year old. It takes time for the pasture to establish and the soil organic matter and root systems to have a sponge effect and tolerate large animals. That is why we graze sheep at first (and throughout) the rotation and bring cattle in only after a year and only seasonally when the risk of soil saturation and compaction is low.

      Having non-crop quality land in the area or partnering with a cattle producer who can bring in stock when it is suited to your operation may be a good way to go. Or consider sheep if you are not going to be putting in pasture and simply grazing annual crops. Sheeping off a cover crop could lower your costs as the plant biomass is converted to manure on-site and may lower costs associated with mowing or heavy tillage of green manure.

      • Jason, thanks for this helpful contribution. I love the phrase, “sheeping off a cover crop”!

  • Bob Williams

    I find it interesting that this article fails to point out that university research has been repeatedly cut. This leaves corporate research as the de-facto research in agriculture. There is no conspiracy in this, just business.

    As for Ms. Stillerman, I would have hoped that she would have a background in science rather than a master’s degree in public affairs and environmental policy. As such, I must wonder just how much of her article is policy and how much is actual science.

    I find great fault with her statement, “In fact, just the opposite—the more farmers are convinced they can’t be profitable without pricey inputs, the better the companies’ bottom lines will look.” Farmers are always looking for new and innovative ways of remaining profitable and would like nothing more than to reduce their dependence on pesticides – they cost too much! Co opting this research in an attempt to bolster a position is intellectually dishonest at best.

    Articles such as these are the reason that we cover the “Union of Concerned Scientists” in my classes and discuss why the talking points should be taken with a “grain of salt.” This article will be discuss this coming Tuesday.

    • Doug Gurian-Sherman


      As a colleague of Karen’s, with a Ph.D. in plant pathology, I endorse her comments. Arguments like yours that are largely based on focusing on someone’s background rather than the data they present are beside the point. Someone who purports to to address science will address the data, not personalities.

      The decisions to favor private over public funding of research is a political one. That may or may not be “business as usual,” but in any case is a policy decision that can be evaluated on its merits. “Business as usual” also gives us climate change, so that does not impress me as a valid justification of anything. And it has big implications for the independence of science. Public-private partnerships have the benefit of pumping more money into research, but at a cost to academic freedom, such as restrictions on the ability of scientists to perform the kinds of research they think are important, as was illustrated in an article in the NY Times in 2009 ( ) As that article pointed out, many scientists are afraid of speaking their minds for fear of offending private sector funding sources, as was the case for the 26 entomologists who wrote to EPA complaining of corporate research restrictions, but requested that their names not be revealed for fear of loosing funding or other negative repercussions.

      Certainly farmers want to maximize profits and cut costs. But the profitability of farms is a lot more complicated than you suggest. A big part of it has to do with policies that subsidize industrial models of production over others, both through direct payment, insurance, and a research infrastructure that has been investing heavily in those kinds of agriculture for many decades.

      In addition, the pollution caused by our farming is an economic externality. In other words, it is not captured in the economics of the farm and farmer, but instead we all pay the cost in dead zones in coastal waters that impair fisheries, polluted wells in the Midwest, sinking aquifers, and so on. So these impacts do not show up on a farmer’s balance sheets, but nonetheless have real economic costs to society.

      Science moves on, and it has become clear over the past 10 years that that low-input farming based on sound biological principles is the way to go. It takes a while for an entrenched infrastructure to catch up.

      • It would have been much more helpful if you, Doug Gurian-Sherman, were to have written this post. There was so much innuendo and so many condescending value judgments in the article as written that I couldn’t even follow most of it.

        Crop rotation is encouraged in the book of Genesis. Or maybe Deuteronomy, I don’t remember. Agribusiness isn’t keeping secrets, nor deceiving atheist farmers (non-Bible readers).

        Midwestern farmers aren’t the intellectual simpletons that the article seemed to imply. Even small farms need to know about how to hedge in physical commodity markets, as well as care for their livestock and let their fields lay fallow on a rotational basis.

        As for pesticides and herbicides, less is best, true. But also ask most residents of Pakistan today, about Monsanto. Many consider a former Monsanto employee, now deceased, in the highest regard, for helping end famine in Pakistan. There’s even an article in Wikipedia about it. Most Pakistani men of my acquaintance are not well disposed toward the USA at the moment. So they clearly aren’t biased in favor of American big companies! As Henry Kissinger said, however, “Moderation is a virtue only in those who are thought to have an alternative.”

    • Bob, thanks for reading. I am sorry you find my academic background lacking, but I have worked with scientists for many years, and I have plenty of them (like Doug) around me every day to ensure that I am reporting on studies such as this one accurately. I certainly don’t think I have “co-opted” this research in any way.

      But hey, don’t take my word for it. I hope that you and your students will read the peer-reviewed paper (it’s freely available at PLOS One, and decide for yourselves whether its findings are valid and what implications it has for the profitability of American farmers.

  • Cal

    So now we should eat MORE meat? Whew, that was a close one because we were nearly brainwashed into believing meat production is dooming us through water depletion. But, now not so much?

    And we should use less corn and soy. OK, we can always put fossil fuels back in to supply energy and plastics currently produced from corn & soy substitutes. That’s more convenient and cheaper anyway.

    Oh, great day in the morning. This will be a truly revolutionary transition of agriculture back some 40 or 50 years. I can taste the yummy pot roasts and mashed potatoes and dark gravy already! Let’s get going, the sooner the better!!

    • Tourm

      “So now we should eat MORE meat? Whew, that was a close one because we were nearly brainwashed into believing meat production is dooming us through water depletion. But, now not so much?”

      Nowhere in this article is a total increase of meat production advocated. It only suggests integration of current meat/veg farming practices.

      “And we should use less corn and soy. OK, we can always put fossil fuels back in to supply energy and plastics currently produced from corn & soy substitutes. That’s more convenient and cheaper anyway.”

      As far as I am aware, producing plastics and biofuels from high-intensity farming is not pollutant-free or even carbon-neutral. Regardless, a global planned economy is not the subject of the article, and sourcing of plastics seems somewhat beside the point in discussion.

      “Oh, great day in the morning. This will be a truly revolutionary transition of agriculture back some 40 or 50 years. I can taste the yummy pot roasts and mashed potatoes and dark gravy already! Let’s get going, the sooner the better!!”

      You may have missed the paragraphs explicitly stating modern agrichemicals were found to be still essential to maximising yeilds in any crop rotation system. You may have also confused an evaluation of profitability through intelligent land use and reduced spending on pesticides/fertilizer with a political essay on the evils of technology.

      I am not sure what point you are trying to make here, save that you are terrible at reading comprehension and have a poor grasp of sarcasm.

    • Cal, thanks for your comment. Though I have to admit, I am scratching my head trying to figure out how you heard me (or the Marsden study authors) saying anybody should eat MORE meat. As your fellow reader Tourm has already noted, that’s not what we’re saying at all. And for UCS’s part, we have pretty consistently said (HERE:; HERE:; HERE:; HERE:; AND HERE: that Americans should eat less—but better, healthier, more sustainable—meat and other animal products, and that public policies and research should help make that easier and more affordable.

      • Jasper

        So you’re going to grow more clover and alfalfa for livestock feed…but you’re not going to eat the livestock? Will they be kept as pets?

        I agree with Cal there will be more meat to eat and that’s fine with me too. Hey, livestock will always be part of any sustainable rotation. A critical link in the cycle, no?

        Beef — it’s what’s for dinner!

    • Jasper, thanks for reading. I am beginning to suspect that you and Cal are purposely misunderstanding me, however. Let’s be clear–less meat doesn’t mean no meat. Of COURSE the feed and forage crops in these longer rotations are for livestock destined for the dinner table. Where an integrated system differs from today’s dominant system is that those feedstuffs are grown close to the animals, and the manure is readily available to the crops. It cycles nutrients more efficiently and saves fuel and money that would otherwise be used to truck both resources long distances.

      • gregfullmoon

        Hey Cal and Bob, it might be that you can eat the meat from the USA and not have to import it from South America where it is implicated in the destruction of Rainforests, necessary for the absorption of CO2 from agriculture in the USA and the West generally..
        and I’m not even a scientist, you guys are joking right??

    • Cal,

      40% of the US Corn Crop is fed to livestock today, requiring increasing amounts of fertilizers and pesticides. No one (but you) are saying produce more meat, just produce more of it on forage rather than grains, reducing inputs, reducing impact, and increasing profitability.

      For the past 8,000 years agricultural advancement meant increased crop rotations. In 1950 U.S. farms produced 5 crops per farm per year (livestock, vegetables, grains, etc). Now farms produce only 1.2 crops per farm per year, resulting in topsoil loss, increased fertilizer and pesticide use, and now reduced profits. So it is your “modern” agriculture that has put us back 8,000 years. Studies like this one are helping restore some clear-headedness after a 50 year chemical binge.

      Fortunately research like this highlights the wisdom of incorporating good agronomic practices into modern agriculture, as it takes thoughtful work to create superior, sustainable agricultural systems for our future. Thanks to the scientists doing the work, and to the authors who write about it.

      Craig Wichner
      Farmland LP

      • Craig, thanks for reading, and for your comment. As you suggest, the research described here shows us a way forward to a truly modern, science- and knowledge-based way of producing the food we need without destroying the resources that future generations will rely on. Thank you for helping to spread the word.