Field Trials to Evaluate N Export from Perennial Groundcover Corn Systems
Corn and soybean dominate the Midwestern landscape. Both are annuals, only present on the landscape for a fraction of the year. In their absence, they cannot intercept and protect soil from rainfall, nor can they slow runoff and promote infiltration. Members of the research team pioneered a perennial groundcover (PGC) system for corn, wherein a summer-dormant perennial groundcover, such as fescue, provides year-round soil cover. Managed correctly, the corn thrives because the cover is dormant in the summer. The PGC approach requires fewer late and early-season field activities, which are barriers to wider adoption of annual cover crops. Modeling predicts that PGC-corn can reduce runoff, enhance soil organic matter and reduce nitrogen leaching. However, further field research is needed to validate modeling to better understand the impact of a PGC-corn system on nitrogen loss.
This project will provide experimental data that can be used to validate models and to estimate the potential impacts on nitrogen-export of widespread PGC-adoption.
Researchers will implement PGC-corn treatments at ISU’s Northeast Iowa Research and Demonstration Farm to monitor the surface and drainage water volumes and macronutrient concentrations and compare to long-term controls at the same site.
Activities during this period:
- Established perennial groundcover (Kentucky bluegrass) on three plots at Northeast Research Farm.
- Planted cover crop (cereal rye) on three other plots at NERF 3.
- Applied manure to 12 plots (3 PGC treatments, 3 cereal rye cover crop treatments, six interseeded cover crop treatments).
- Conducted preliminary soil sampling for phosphorus and basic soil chemistry on all 12 plots.
- Recruited graduate student on project.
- Determined proposed seed mix for interseeding cover crop.