Last week we introduced Michael Shermer’s “Baloney Detection Kit” questions along with an example of how Kathy got bamboozled by not asking these questions that would have saved her $10. This week, we’re going to show you how we used those questions when we looked at couple of practices that have been recommended to producers as ways to improve their sustainability and profitability.
The Yeoman’s Plow and Keyline Plowing
The two part series we published in 2013 on Keyline plowing covered research done by Rachel Gilker and colleagues to see if using the plow and the keyline system resulted in the claims that had been made and that had Vermont farmer’s intrigued and hopeful. We won’t go into all the details of the study here, (those are covered in these two articles: “Keyline Plowing: What is it? Does it work?” and “Keyline plowing results: 522,720 worms for $280“), instead, we’ll show you how we use The Questions to give us an idea of whether or not this is a practice we’d recommend jumping into.
First, here are the claims: Simply described, keyline plowing is a system of subsoiling using something called a Yeoman’s plow, a thin-shanked plow, with shallow angles on the feet of the plow. To keyline plow, the farmer must first determine the “keyline” of the slope, where the hillside shifts from convex, toward the foot of the slope, to concave, toward the top. The Yeoman’s plow is then used to create channels parallel to the keyline, throughout the targeted landscape. The idea is that these channels will distribute water from wet areas to dry areas. According to claims, this will reduce compaction, enhance plant growth, and speed soil building, as in 8-12″ or more of topsoil per year.
We skipped right to Question 4. “Does this fit with the way the world works?”
No, it doesn’t. Research has been done the world over, by countless soil scientists, for years and years and years, all coming to the conclusion that it takes decades and even centuries to build topsoil.
How about Questions 3, 5 and 8? Have the claims been verified by someone else? , Has anyone tried to disprove the claim?, and Does the claimant provide positive evidence?
Rachel found no evidence, data, or research either proving or disproving the claims about keyline plowing. There are pictures, and yes, pictures can be worth a thousand words. But they’re only valuable if you have information to go with them about what happened before the picture was taken. Meanwhile, when Kathy first heard about keyline plowing, she was told that it was a common practice in Australia and that ranchers had parked their old plows as decoration at their ranch gates and taken up the Yeoman’s plow instead. After reading studies by Australian soil scientists that corroborated the lengthy process for soil building, she contacted some of them, thinking that perhaps the papers were old and the new practice had changed their minds. They were unaware of the practice and had never seen a plow parked as decoration at a ranch gate.
If you’re a producer, at this point you might choose to move on without trying this new idea because it’s expensive to attend the keyline courses and to rent or purchase a plow and invest time in the practice. You might not want to make the investment without a better guarantee of a return. But at the time, Rachel’s job involved helping farmers figure out if new practices were worthwhile so she worked with four of them in Vermont for 2 years to test the keyline process. As noted in the articles on her research, they found no changes as a result of keyline plowing other than an increase in worms.
Now, as scientists, we’re perfectly willing to change our minds should more information become available. If anyone out there has data to share, do send it on!
In most cases the process of developing scientific knowledge is one of scientists building on or taking apart each others’ theories and studies. By testing theories and re-working studies, we get new information, and reach stronger conclusions than we would by working alone. Scientists may even change their minds about theories based on this new information. That may seem wishy-washy, but to scientists, changing your mind when you get new and better information is what makes us smarter. But scientists are only human, and in some cases, in spite of what the data shows, a human being might choose to go with his preferences instead.
Soil balancing is a good example. Beginning in the late 1800s, scientists began studying soils, learning about nutrients and trying to figure out if there was a ratio that helped plants grow best. They were hoping for that magic bullet that we all dream of and a couple of scientists proposed ratios for Hydrogen to Calcium to Magnesium to Potassium. You can read about their studies in this On Pasture article, but right now we’ll jump to the chase and tell you that all but one person ended up refuting the soil balancing concept.
Here are the questions we asked and the answers we found when we put together that article:
Have the claims been verified by anyone else?
No, they haven’t.
Has anyone tried to disprove the claim?
Yes, and the theory of ideal soil ratios has been disproven over and over again.
Does it fit with the way the world works?
No, the research shows that plants grow well in a wide variety of ratios. The limiting factor is typically calcium, which increases when well-meaning land managers make changes to reach this so-called “ideal soil.”
Where does the preponderance of evidence point?
To the fact that this theory is false.
Yet even today, many still think that the effort they are making to balance their soil is having an effect. So what did scientists do? They studied what was going on in these cases and determined that it is not the soil balancing that is improving the soil, but the other practices being done in conjunction with it like applying compost or lime, and planting cover crops.
So should you practice soil balancing? If you’re still convinced that it is a useful practice, we suggest you balance the cost with the benefits and perhaps look at the other things you’re doing and consider whether or not they would get you the same result for less money. In fact, that might be a research project you could do on your own place. So next week we’ll share some information about how you can do a little research without too much investment.
Here’s the third and final article in this series: