Sustainable agriculture is not enough
Roger Zylstra harvest soybeans on his farm near Kellogg, Iowa, in 2017, working into the night to catch up after a wet week. Rodney White and Michael Zamora/The Register
Iowa is a thermonuclear-powered photosynthetic manufacturing machine for calories and BTUs.
This is how I have thought of the agricultural industry in Iowa for many years, but it really started millions of years ago. Not just a few, but 350 million years ago. This is when the vegetation produced by this photosynthetic machine started turning into coal. We can refer to this as “old sun” since the BTUs of this “sunlight-produced jungle/prairie” were buried underground and converted to coal through time, temperature and pressure. Estimates by JH Lees in 1927 indicated we had 30 billion tons of coal in Iowa, enough to last us for 3,000 years.
Herein lies our problems. It took us 350 million years to convert sunlight to coal, and we could use it up in 3,000 years.
Let’s look at soil.
For the last 12,000 years, since the last of the Wisconsin glaciation receded, leaving a pretty flat, slightly rolling landscape, Iowa has enjoyed a spring, summer, fall and winter. These four distinct seasons helped to produce vast prairies of biomass that grew, flourished and died every year. This natural cycle of nature resulted in building up to 12 feet of the most precious, luscious and high-animate matter topsoil in the world.
“Despite all our achievements, we owe our existence to a six-inch layer of topsoil and the fact that it rains,” says the farm equipment association of Minnesota and South Dakota.
Just as it took 350 million years to make the coal under Iowa, it took 12,000 years to make the soil that sits on top. Every year, we convert millions of Joules (a measurement of sunlight energy) to corn, beans, pasture, prairie and trees. That is more than 15 million megawatts of power that we convert to vegetation which stores this energy in crops until we need it. To compare this to wind energy, Iowa has the ability to produce 6,300 megawatts of electricity.
And that is where I start the real story.
Our soil, our average annual rainfall, and our growing degree days all contribute to our ability to make carbohydrates and/or oils from various seeds. In the old days when we shipped lots of corn outside the state, we exported these calories/BTUs from our photosynthetic machine to other places. We finally figured out that if we wanted to keep all these calories in the state and make better use of them, we had to re-convert the photosynthetic calories to other products with more value to them. So we expanded the animals that consumed these calories (pigs, chickens, cattle and turkeys) and built ethanol and bio-diesel capacity to re-convert this photosynthetic storage device (corn and beans) into vehicular fuel.
As a result, we find ourselves in this cycle of working harder and harder to photosynthetically convert more and more sun to carbohydrates and oil and vegetable protein. We accomplish much of this by turning it into meat, milk, eggs, fiber, food and fuel. But there’s the problem — we are using up our soil to do this, and we are not putting enough back to keep up with the loss. We have lost half of the 12 feet of topsoil in Iowa in the last 100 years. Six feet, gone! And it’s almost impossible to replace. If we are really intentional and work hard at it, we can make an inch of soil in 500 years. It will take us three times as long just to replace what we’ve lost than it took to build the original 12 feet of topsoil in the first place.
I still believe in exporting calories from Iowa, in the form of feed, food, fuel and fiber, as this is a great way to provide the benefits of Iowa's photosynthetic machine to others. But we must protect our most valuable asset, the one that took 12,000 years to make, and less than 100 years to cut in half: our precious soil. Sustainable agriculture is not enough. We need regenerative agriculture to keep on supplying our thermonuclear-based photosynthetic bounty to the rest of the world.
To quote Thomas Jefferson: “While the farmer holds the title to the land, actually it belongs to all the people, because civilization itself rests upon the soil."
Riley is chairman of the board and founder of Feed Energy in Pleasant Hill. Feed Energy provides high-energy feed ingredients for poultry and pork producers throughout the Midwest.