Working Within Our Current System: A Conservation Chat with Eileen Kladivko

Cover kladivko_creditHost Jacqueline Comito sat down with Dr. Eileen Kladivko, Professor of Agronomy at Purdue University and founding member of the Midwest Cover Crops Council (MCCC), for the most recent episode of the Conservation Chat podcast.

Eileen Kladivko’s chat covered many issues areas that she has studied for decades surrounding soil health, cover crops, earthworms and drainage. To start the chat off, Eileen wanted to make something clear: drainage is essential.

“I like to remind people that we wouldn’t be growing crops at all on some of our most productive lands in the Midwest if we didn’t have tile drainage.”

Tile drainage is essential if we want to farm much of the land that we currently farm – especially in Iowa. While there are benefits to tile drainage, a drawback of the system is the movement of nitrate with water that flows out of tile lines and into the surface water. How can we begin to solve this challenge? Mimic nature and the system that we replaced, Eileen suggested.

We’ve got agriculture, we’ve got lots of human beings here, and we want to be productive. We want to mimic nature where we can, but we’re not going back to pre-settlement conditions. That’s impossible. But let’s see if there are some things we can learn from what the vegetation cycles were, and the hydrology cycles, that can help us with our current system.”

Adding cover crops to our current system is one way to address our nitrate challenge and to mimic the natural vegetation cycle that once existed on the land. Cover crops have seen a steady increase in popularity, and for some farmers, the desire to grow something comes naturally.

A subject that Eileen Kladivko is most passionate about is soil health. Soil health is a popular topic because we want our soil to function to full capacity for crop production, but we understand relatively little about the soil biology that can shape the physical and chemical properties of soil. In recent years, the soil health conversation is shifting to research about soil biology. The downside is that soil health research takes time.

“That’s one of the challenges with the whole soil health thing . . . we’re trying to look at some of the commercial soil health tests that are available right now and see which of those might actually be able to detect changes with time in some of our Indiana sites. It’s quite challenging because the tests are quite variable. Soil health does take time to improve, and sometimes those tests just don’t show it over the short term.”

Without lab tests to show short-term gains in soil health, there is one indicator that can give farmers a short-term pat on the back: earthworms! Earthworm populations are highest in systems with limited tillage and high levels of crop residue. Eileen has spent much of her career counting earthworms.

“I didn’t think that was going to be a long-term commitment of mine,” said Eileen. Decades later, Eileen has developed a foundation for research on the physical and chemical properties of soil as they relate to soil health and good soil biology.

What are your chances of having a high earthworm population within a system that includes tillage? Not likely. Switching to no-till and adding a cover crop will increase your chances to see early signs of soil health and good soil biology before other commercial soil health tests are able to show results. Iowa Learning Farms has seen similar results when counting earthworms under different tillage and cover crop systems here in Iowa.

Listen to the full Conservation Chat episode! If you’re on the go, take the Conservation Chat podcast with you – find it on iTunes or search for “Conservation Chat” on the podcast app of your choice!

Julie Whitson

Earthworms serve as Indicator of Soil Health

A friend of the farmer, gardener, and angler alike, the earthworm may help to unlock the secrets of the soil by serving as an early indicator of soil health!  Anecdotally, farmers have expressed benefits to using cover crops and noted improvements to their soil, but quantifying changes in soil health can be complex to measure (and require years of intensive sampling). That’s where earthworms come into play!

Thanks to funding from a USDA-NRCS Conservation Innovation Grant, the Iowa Learning Farms team is studying the common nightcrawler, Lumbricus terrestris, and investigating its population dynamics in agricultural ecosystems.

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In particular, we are conducting midden counts at seven sites across the state (6 on-farm demonstration sites, 1 research site), all managed as a no-till corn/soybean rotation.

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Within that system, we are evaluating earthworm populations on side-by-side strips with and without cereal rye cover crops.  Read more about the study in our earlier blog posts Guest Blog: Digging for Worms and Midden Madness.

What have we found?

The midden counts conducted in June 2016 indicate that on each site, strips with a cereal rye cover crop have comparable or higher earthworm counts than those without a cereal rye cover crop …

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Looking at all sites together across the board, we see statistically significant differences between the strips with a cereal rye cover crop and those without. Based upon this preliminary data set, we are seeing 38% more earthworm middens with a cereal rye cover crop!

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If you’d like to learn more, I just gave a webinar earlier in the week on this topic. The archived webinar can be viewed on the Iowa Learning Farms webinar page (along with all of our previous webinars). Click on the November 16 webinar to view Earthworms and Cover Crops: Unlocking the Secrets in Soil!

Ann Staudt

This material is based upon work supported by the Natural Resources Conservation Service, U.S. Department of Agriculture, under NRCS Conservation Innovation Grant 69-6114-15-005.