Should prairie potholes and other wet areas be farmed?

If you farm in the Des Moines Lobe, you know a thing or two about growing corn and soybeans in prairie potholes. They don’t usually yield as much as other parts of your field and they can often cause planting to be delayed in the spring. Perhaps it is time to consider a more economical and environmental land use for those areas.

Prairie potholes account for approximately 3.5 million acres (44%) of the Des Moines Lobe landform. These soils were naturally wetland soils until intensive agriculture and artificial drainage came into being. Most farmers know these potholes are not holes with clear boundaries. Sometime they can be found in upland locations and other times as riparian wetlands.

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Capture2Through artificial drainage, these soils have become part of the row crop systems common across Iowa. In dry years, even when tiled, these areas are the most productive soils. More often than not, in normal to wet years these areas struggle to be profitable. These soils have poor natural drainage and shallow water tables that limit root growth that makes for a poor productivity soil environment due to seedling diseases, root rots, and poor nutrient uptake.

With that background let’s go back to the title; should prairie potholes and other wet areas be farmed? Even with tile drainage systems, these field areas pull down field average yields more years than not. This question is just as much about the social and economic aspects as it is about productivity. It should be hard to justify high corn and soybean costs of production when the return on investment in those areas is negative 50 to 80 percent of the time. There is an opportunity of land use change in these soils and field areas to minimize nutrient loss, increase wildlife habitat, and provide ecosystems services.

GraphicI truly recognize that ease of farming could be impacted and farming around small areas may not be feasible. I also recognize that this takes a commitment of both the tenant and landowner. Despite the challenges, the benefits are many: higher overall profit margins, reduced nutrient loss, and recreational opportunities through increased wildlife habitat.

Mark Licht

Mark Licht is an Iowa Learning Farms team member and Assistant Professor and Extension Cropping Systems Specialist at Iowa State University.

Wetlands: By the Numbers

Iowa (and much of the Corn Belt) was once characterized by extensive wetlands dotting the vast prairie. As the land was settled, wetlands were drained for agriculture, as well as development of railroads and early community settlements. While wetlands can be found across the state, the majority of Iowa’s wetlands were located in the north central part of the state (Des Moines Lobe).

Created by the last glacier to cover the state 10,000-15,000 years ago, this area was left flattened with thousands of indents when the ice receded. Deep indents became lakes, while the more shallow recesses became prairie pothole wetlands. In some places within the Des Moines Lobe, it is estimated that as many as 200 potholes could be found within a one square mile section of prairie!

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Where have all the wetlands gone?
It is estimated that over 90% of the original wetlands in Iowa have been lost. In the Des Moines Lobe specifically, that number climbs — approximately 99% of wetlands had been lost on the Des Moines Lobe as of the 1970s (Wetland Restoration in Iowa: Challenges and Opportunities/Iowa Policy Project).

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After bottoming out in the 1970s, the tide has slowly and steadily changed. Beginning in the 1980s and continuing through today, more and more citizens across the state are seeing the true value that wetlands provide out on the landscape and have acted towards increasing wetlands acres. Numerous restoration programs have strived to support this momentum, working collaboratively to bring back these vibrant ecosystems on our landscape.

Through programs such as CREP (Conservation Reserve Enhancement Program) and CRP (Conservation Reserve Program), wetland areas are being maintained and restored as we speak. These state and federal programs work with farmers and landowners who would like to voluntarily transition land use from agricultural production to wetlands production.

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Iowa is currently ranked 4th in the country in CRP wetland restoration, behind only Minnesota and the Dakotas (December 2015 USDA-Farm Service Agency Monthly Summary).  Wetlands restoration is making forward progress — good news!  There’s also still quite a ways to go.

Depending upon their placement on the landscape, restored wetlands can offer benefits for water quality (more information coming in next week’s wetlands feature!), wildlife habitat, flood storage, and more. Every additional wetland out there helps!  As Rebecca Christoffel, Wildlife Specialist with the Snake Conservation Society, emphasizes in the video Incredible Wetlands,

“Iowa has already somewhere between ninety and ninety-nine percent of its wetlands. In my view whether it’s a recreated wetland, if it’s a restored wetland, or if it’s a constructed wetland, that’s still a positive move.”

Catch up on our previous features celebrating American Wetlands Month:

Ann Staudt