By Scout Nelson
Cover crops play a vital role in protecting and enhancing soil health, especially in regions where harsh climate conditions limit the planting window each fall. These crops help reduce soil erosion, boost organic matter, and capture excess nitrate before it can seep into groundwater sources.
Recognizing the importance of cover crops, the University of Nebraska–Lincoln launched the Highboy Cover Crop Interseeding Project in 2022, in collaboration with the Nebraska Department of Environment and Energy and participating Natural Resources Districts. The goal is to identify practical solutions for establishing cover crops and to measure their influence on water quality.
In fall 2024, approximately 1,100 acres on multiple fields were interseeded into corn at the R5.5 growth stage. At this phase, the corn canopy is more open, allowing sunlight to reach the soil surface for covering crop establishment.
Because rainfall was sparse, operators were encouraged to irrigate at least half an inch following interseeding to ensure robust seed germination. The broadcast cover crop mixes often included cereal rye or a combination of cereal rye, rapeseed, and turnip at around 70 pounds per acre.
An additional 800 acres were reserved for drilling cover crop seed after soybean harvest, following a three-year rotation protocol of corn-soybean-corn. These fields received either winter wheat alone or a blend of winter wheat, turnip, and rapeseed. The drilling process typically occurred once the soybean residue was cleared, allowing for adequate seed placement and improved soil contact.
Preliminary stand counts, taken in mid-November 2024, suggest variable emergence rates between R5 interseeded fields and post-harvest drilled fields. Some sites showed promising germination levels, while others experienced lower percentages of living plants.
This difference may reflect the extremely dry conditions recorded in September 2024, marked as the driest on record in Nebraska. Where irrigation was limited, cover crop seedlings struggled to establish.
Researchers will continue monitoring these sites to measure spring biomass production in 2025 and assess soil nitrate dynamics. These evaluations will help determine how effectively cover crops that capture excess nutrients and contribute to long-term environmental health.
By refining interseeding and post-harvest planting strategies, this project aims to support sustainable farming practices and protect Nebraska’s vital water resources for future generations.
Photo Credits:gettyimages-eugenesergeev
Categories: Nebraska, Crops, Weather