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