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Within the farming community — and especially among Practical Farmers of Iowa members — there is a renewed focus on soil health, its role in crop productivity and environmental conservation, and the role played by soil microbes and farm management practices.
On Practical Farmers’ 2017 member survey — a comprehensive questionnaire we send out every few years to learn more about our members, their goals and priorities — soil health ranked third among a long and varied list of priorities. We heard the message loud and clear, and are responding with a suite of soil-focused sessions at our upcoming annual conference (Jan. 18-20, in Ames). Among them, we’re pleased to bring expert no-till and cover crop farmer Keith Berns to Iowa from south-central Nebraska.
Keith is a former teacher who no-tills 2,500 acres of irrigated and dryland corn, soybeans, rye, triticale, peas, sunflowers and buckwheat near Bladen, Nebraska, and also co-owns Green Cover Seed, one of the of the major cover crop seed providers and educators in the U.S.
A few years ago, Keith developed the concept of “carbonomics,” a framework for thinking about soil health in terms of economic principles. I chatted with Keith to learn more about this unique approach to understanding the bigger picture of soil health and its complexities.
(Note: Keith will be teaching an in-depth session on carbonomics at our conference, as well as a session on the SmartMix Calculator he developed for selecting the best cover crop species mixes. Learn more or register on our 2018 conference website.)
What is “carbonomics”? How did you come up with the concept?
It came about a few years ago. I was visiting with Kristine Nichols, who works with Rodale Institute now. We were talking about the whole concept of carbon being a currency, that that really drives the whole system. Based on that conversation, probably four years ago, it kicked around in the back of my mind how plants are using carbon to buy things from the biology.
So the concept of it being an underground economy was kicking around in my head. As I was laying out the principles of economics – supply, demand, energy, resources, infrastructure, etc. – everything lined up very well from what I knew about the soil. I sat down one evening and mapped out the rough outline, then spent a fare amount of time filling in the gaps.
The result is that everybody – especially non-farmers – can listen to that and have a much better appreciation of soil health. Everyone understands an economy, even if they don’t know it. You live in an economy, you function it in every day, work in it. This gives you a framework to be thinking about soil health.
So in this framework, carbon is like cash that plants use to buy things. How does the metaphor translate into soil health and farm production practices?
Everyone understands cash: You can only grow your savings account when you have more cash than you spend. If you think of carbon as cash, the only way you can build your soil organic matter is if you have excess carbon.
As a general rule, we’ve lost vast amounts of carbon because of tillage and other practices, not having cover crops. That’s in essence like running up a national debt. We were spending more than we were earning. If you look at Iowa, at the amount of carbon that would have been held collectively in Iowa soils 150 years ago versus the amount of carbon in Iowa soils now, it’s probably less than half. The same thing could be said for anything that’s been farmed for 100 years.
In a strictly corn-soybean rotation, I compare it to someone living paycheck to paycheck. You’re getting by, making ends meet, but not building up the soil. That’s where cover crops come in. It’s like having a second job or getting a raise. The soil system has extra carbon ‘income’ so you can start growing your organic matter levels. When you introduce cover crops you help carbon rise in the soil, so you see your organic matter rise.
How quickly do you see those soil health benefits from cover crops?
Organic matter tends to builds fairly slowly – although some people have seen significant gains in a short amount of time. A lot of that [rapid gain] happens when you make pretty radical changes — so not just doing corn and soybeans, but incorporating wheat, which is a high-carbon crop. With wheat, you could almost do two rounds of cover crops between wheat and corn the next year. Some people are bringing livestock into the system too.
There are ways you can get fairly quick increases – but I don’t want to get farmers thinking that if you do this, you’ll get a 1 percent organic matter increase per year.
The other thing is, if farmers try to take cover crops and just squeeze them into what they’re already doing, they’re probably going to fail. It’s a systems approach, cover crops, and can’t just be forced in there without some type of disaster. You need to look at whole system and how cover crops fit as part of that.
For example, a farmer willing to grow wheat for a year and have a cover crop after that will see faster changes than the one doing only corn and soybeans. Farmers willing to maybe put 2.4 maturity soybean instead of 3.5 maturity will have more success than the farmer that gets it planted late every year.
For farmers who’ve never planted cover crops before, one hesitation I’ve heard to trying cover crops is how long it will take to see benefits versus the challenges of adjusting their management.
In a corn-bean rotation, you’re not harvesting anything until October, so you don’t leave a lot of time for your cover crop to grow and you either have limited growth or limited benefits. It’s still better than having nothing [growing in the soil], but benefits will be pretty slow.
The other thing is when you plant a cover crop that late, you really have to plant something that will overwinter, which really limits your choices and also creates a higher burden of management in the spring. If you’re not prepared to terminate in the spring, you can really get into trouble for the next crop.
For example, cereal rye is probably the number-one cover crop in Iowa and the U.S. It’s really cold tolerant and works really well – but it’s a really aggressive scavenger of nitrogen. Ahead of soybeans, that’s a good thing and a good fit. But it can be a really bad thing for corn — corn can be yellow, and farmers will probably blame the cover crop, which is partly true, but it’s partly a timing issue.
So a higher level of management is needed when you have cover crops that overwinter into the spring, versus someone planting wheat, which winter-kills in October, and then you don’t have to deal with [those issues] in the spring.
Soil is one aspect of farming that unites virtually all farmers — how the soil functions affects a farmer’s operation, and it plays a big role in ecosystem health too. Most farmers strive to care for their soil in one way or another, yet soils are increasingly stressed — from erosion, nutrient loss, diminished microbial communities and other pressures of modern farming — and this also has big ripple effects on the environment.
Are there any key messages about soil health that you think farmers need to better understand? Is there a disconnect between knowledge of soil health and practice of soil stewardship?
The biological component of the soil is the one we understand the least – and especially anyone who’s been through an agronomy program at university. They probably had very little time dedicated to soil biology. If you take a soil biology class, you will talk about physical and chemical properties, but very little on soil biology.
Soil can only be healthy if it has that living component. I really try to stress that in the “Carbonomics’ talk: that biology only works when all three – the physical, chemical and biological – are contributing to the underground economy.
With industrial farming, we’ve ignored the biology. The plant suffers, looks yellow and sick, and so we come in and spray or fertilize. In economic terms, that’s providing welfare – I call that ag welfare. We have to step in and basically give handouts to the plants, because the soil economy can’t support it.
In a healthy economy, you shouldn’t need much of that. In a healthy soil economy, it should be able to function on its own.
It sounds like your session on “Carbonomics” will appeal to both farmers and non-farmers alike.
This talk is really big-picture, the theoretical part of soil health. There will b very little practical information as to how it applies to your own farm. I’ll give some examples of how it applies to our farm, but the focus will be the big picture: how all the pieces and parts interact – principles and not practices, and those principles apply to any soil, any crop.
SmartMix: Started as Excel spreadsheet that we would use to put mixes together that we were using on our own farm. I wanted to know what percentage I had of peas vers other things. Started out that way, and I started adding some of the factors, because we knew some things did better for weed suppression, some things did better for covering the soil.
You’ll also be teaching a session on the SmartMix Calculator for cover crop selection. Tell me a bit more about how that came about.
I started adding those details to a spreadsheet, which I used internally for two or so years for our own internal business decision-making. Then I found a little program I could buy, like an Excel spreadsheet, that compiled the information to an HTML file for use on the internet. Once I found that, I realized I could put it out for other people to use.
The SmartMix Calculator has gone through quite a few iterations. One of the things that it’s always had from the beginning that sets apart from other tools is it will give you a real-time cost of what that mix will cost you per acre.
It doesn’t matter if you have the nicest mix. If it costs you $70 per acre, it doesn’t matter – no one will do it. [The calculator gives you a] real-time cost because you can punch a button and order right from our site.
I ran it on that spreadsheet for a couple of years, but I wanted to take the calcular further beyond what Excel could do, so at that point, I had to take it all to computer code and write a custom program to do the same thing.
My son has actually done all the programming; he has an IT degree. I had all the algorithms and he had the knowledge to integrate it into a very user-friendly system, to the point that now that you can put in your own zip code and it knows where you’re at, your growing-degree days, your first and last frost dates, the precipitation you get every year — it uses all that geographic information to help select the best cover crop species for you.