Iowa State’s Dr. Matt Liebman is a professor of agronomy and holds the Henry A. Wallace Endowed Chair for Sustainable Agriculture. He studied biological sciences at Harvard University and earned his Ph.D. in botany from the University of California-Berkeley. At ISU, he focuses on how to use ecology to maintain or increase agricultural production while reducing dependence on chemicals and fossil fuels.
Now I’m sure a lot of you will look at his Harvard and U.C.-Berkeley background and dismiss him as another East coast/West coast elitist trying to preach nonsense to the real folks in flyover country. To those folks, let me grab you by the scruff of the neck and point out the years he has spent working in the real world, flyover country around Iowa State University, one of the top ag schools in the country. He digs in the dirt, plows it up, plants crops and carefully gauges the results. He has mud on his boots and dirt under his fingernails.
Not too long ago, he completed a long term study on the effects of increasing the number of crops in a rotation sequence. What he did was ask an interesting question about our current practice of a two crop rotation: Corn and soybeans. We know what it does to the soil and the amendments needed to maximize production. What happens, though, if we add one or two more crops to that rotation?
Of course greater crop diversification has been the constant chatter from folks who fear we are losing the plant DNA that has sustained us for centuries. To maximize production, an important step to making sure farms are economically viable and they can produce enough to feed a hungry world, they say we are ignoring heritage seedstocks and that is a dangerous tradeoff. To the alarmists, the trend toward monoculture creates an unnatural and harmful reliance on fertilizers and pesticides.
Let’s be fair. ‘Alarmist’ is often used as a dismissive term similar to ‘Chicken Little.’ Can we rephrase and use ‘whistle-blower,’ a term that often describes someone who notices real wrong-doing and calls attention to the problem? The catch, I think is ‘real wrongdoing.’ Where is the hard evidence that current practices are potentially bad for the future of agriculture and that ‘multi-cropping’ can hold its own against the proven advantages of a two crop system?
Dr.Liebman’s crew established a powerful argument for multi-cropping. Their study showed that it can lead to a reduced reliance on herbicides, pesticides and artificial fertilizer, and less use of fossil fuels – four things that might mean better sustainability.
Q: You and your colleagues have recently completed a long-term study on the effects of crop rotation. What was the impetus behind the project and what did you hope to learn?
A: We started with the assumption that for any production system, there is a need to balance productivity, and protection of environmental quality. We conducted the experiment to learn how increasing the number of crops grown within a rotation sequence and the integration of crop and livestock production affected
(1) requirements for fertilizers, herbicides, and fossil fuel energy;
(2) crop yields;
(3) production costs and returns;
(4) weed dynamics; and
(5) impacts on the environment, specifically toxicity to aquatic organisms.
We hypothesized that diversification and integration could lead to large reductions in agrichemical and fossil energy use, while maintaining or improving productivity and profitability, and greatly reducing impacts on the environment. We were right.
Q: Your study was based on small plots of land in the heart of very large farm country. Is what you’ve learned really applicable to modern, large-scale farming? Is what you’ve learned really scalable?
A: Yes, it’s applicable to large-scale farming and yes, it’s scalable. We based the treatments in our study on what is already being done on conventional and more diversified, more integrated farms in our area. Some of them are large.
Q: There is wide-spread assumption that world agriculture will have to greatly increase its output. In June, 2011, Bloomberg News reported “Global agriculture production needs to increase 70 percent to meet food demand by the middle of the century.”
On the surface, that statement suggests a continued move toward large scale farming. Doesn’t your study suggest we take a few steps back in time and can we really count on it to help boost productivity?
A. We used modern crop genetics, fertilizers, herbicides, and farm machinery, and information-intensive management practices, and we achieved yields that were at or above the county averages. The principles we applied may have been used in the past, but diversification and integration are as relevant today as they were in the past, especially if you believe that agriculture must reduce its negative impacts on water quality and wildlife habitat.
Q: As part of the study, didn’t you use grazing animals – cattle – to ‘mow the lawn’ and fertilize the land, almost eliminating the need for artificial fertilizers? In a recent TED presentation by Alan Savory, he talked about a similar practice to alleviate desertification. Is the raising of livestock, which was once under attack, as ecologically damaging, undergoing a renaissance?
A: In our study, we did NOT include grazing livestock directly. We harvested forage crops mechanically and spread 7 tons/acre (fresh weight) of beef cattle manure once every three years in the 3-year rotation and once every four years in the 4-year rotation.
The amount of manure we spread was consistent with the amount of material that would be generated by the number of cattle that could be supported with the concentrates and forages produced in the diversified rotations. Based on the results of our study, we believe that cattle production can be a very positive component of highly productive, profitable, and environmentally benign farming systems.
Q: How much of the success of your study can be attributed to livestock inputs? And does your study suggest that ‘free-ranging’ livestock is a better management practice than CAFO’s?
A: Our use of livestock manure was important for recycling P and K back to the land that we used for crop production, thus reducing our requirements for synthetic P and K in the 3-year and 4-year rotations. The manure also contained some N, but most of the N in the 3-year and 4-year systems was supplied by residues of red clover and alfalfa.
Q: Last fall, Mark Bittman, a columnist for The New York Times, wrote a column about your work with the rather simple headline, “A Simple Fix for Farming.” He stated, “In short, there was only upside — and no downside at all — associated with the longer rotations. There was an increase in labor costs, but remember that profits were stable.”
With farming being generally a very low margin business, increased labor cost can be called a downside. There is also the corresponding problem of a lack of a good knowledge base. Most farmers are experts in the current two-crop system. Wouldn’t a three or four crop rotation require a whole new learning curve? - And wouldn’t adding livestock to the mix, if they weren’t already there, compound the problem?
A. It’s true that not all farmers want to produce both crops and livestock. Some farmers prefer to raise crops; some prefer to raise livestock. That makes it possible for neighboring operations to be coupled, as well as having crop and livestock operations directly integrated on some farms that want to have both types of enterprises. American farmers are highly intelligent and learn and adapt quickly when they have sufficient motivation and when new opportunities present themselves.
Q: Back to the increased labor costs: It’s becoming increasingly difficult to find farm labor. How much more labor is required and must it be a more skilled work force than we’ve had in the past?
A: All the treatments in our study were fully mechanized. For the period 2006-2011, average annual labor requirements were 0.7 hours/acre for the 2-year rotation, 1.1 hours/acre for the 3-year rotation, and 1.5 hours/acre for the 4-year rotation. Labor costs were small relative to costs for seed, fertilizer, and fuel for machinery and grain drying.
For the period of 2006-2011, non-labor and non-land related production costs were $279, $181, and $203/acre for the 2-year, 3-year, and 4-year rotations, respectively. In contrast, labor costs were $8, $12, and $16/acre for the 2-year, 3-year, and 4-year rotations, respectively. Average net returns to land and management were $387/acre for the 2-year system, $392/acre for the 3-year system, and $369/acre for the 4-year system.
With regard to the policy context that affects farming, you might want to consider that during the period of 1995-2011, Iowa farmers received an average of $1.4 billion per year from the federal government (meaning your tax dollars and my tax dollars). With some rounding, 67% of that went to commodity subsidies, 15% went to crop insurance subsidies, 15% went to conservation payments, and 2% went to disaster payments.
Almost all of the commodity subsidies and crop insurance payments went to support corn and soybean production. I’d like to see my taxes better support soil and water conservation and diverse, integrated crop-livestock systems. How do you want your money to be used?
The opinions expressed in this column are solely those of Chuck Jolley and Matt Liebman.