With the most productive acres in Illinois, McLean County farmers are well versed on effective ag conservation practices. Most cropland is tiled and tillage practices protect against erosion and nutrient loss.
But as farmers attending the July 12 Nutrient Stewardship Field Day at the Illinois State University (ISU) Research Farm found, there is always room for improvement.
The field day was developed from ongoing Lake Bloomington and Evergreen Lake watershed planning efforts focused on educating landowners about plans and practices they can use to help meet watershed goals.
Planning is led by the McLean County Soil and Water Conservation District and McLean County Farm Bureau, the city of Bloomington and Northwater Consulting. Additional field day partners include Illinois Nutrient Research & Education Council, ISU, Purdue University and CoverCress, Inc.
“One of the most cost-effective solutions for watershed improvement may be adding more cover crops for an estimated 32% reduction in nitrates, 18% in phosphorus and 30% in sediment,” said Jeff Boeckler of Northwater Consulting, who is helping to update the Lake Bloomington and Evergreen Lake watershed plans.
That will allow farmers and other groups to determine how best to protect and improve drinking water and find funding assistance for those efforts.
“It may be possible to avoid costly water treatment facility upgrades with agricultural ground improvements, but farmers will need to be incentivized,” said Boeckler.
Farmers and others attending the the event viewed cover crop plots organized by ISU ag professor Rob Rhykerd and several associates, targeted at evaluating several different crops and crop combinations. Innovative studies include measuring the impact of different species on soil organic matter, carbon sequestration, microbial communities and subsequent corn and soybean yields.
Pennycress is one of the unique crops being tested.
Bill Perry, ISU associate biology professor, said work with CoverCress, a new seed technology that has turned pennycress into a rotational cover crop, utilizes nitrates in water in a similar manner to cereal rye while also providing a potential, additional cash crop revenue stream.
Nathan Smith with CoverCress told attendees CoverCress seed will be available this fall as a contract production opportunity in Illinois.
Shalamar Armstrong, Purdue University associate professor of agronomy, shared his cover crop ideas, too, defining next generation cover crop management as practices that maximize production and nutrient use efficiency while minimizing environmental degradation. Armstrong has been working in the watershed to develop recommendations for area farmers.
His work looked at timing for nitrogen applications with and without cover crops and found a 46% to 49% reduction in spring and fall nitrate loss when cover crops were used. On a watershed level, assuming mass cover crop adoption, nitrate loss reduction was in a 33% to 48% range. Nitrogen management alone did not have a significant water quality impact in tile drained systems.
“We also did not see a cover crop impact on soybean yield, but corn had a 6-13% reduction in yield after cereal rye with only a 9-12% recovery of cereal rye N,” said Armstrong. “All cover crops species are not created equal when it comes to DRP (dissolved reactive phosphorus) interaction either; annual rye is better than cereal rye which is better than radish/oats.”
Based on his work, Armstrong’s advice is to consider planting overwintering legumes ahead of corn to get good biomass.
“Inclusion of overwintering legumes has the potential to generate significant nitrogen credits. Precision planting cover crops and using UAV technology so farmers can better manage crops in zones all have the potential to close the yield gap for corn after cover crops,” he said.
Farmers also visited ISU's saturated buffer installed in 2018 to keep nutrients out of the water with use of a drainage control structure on what had been Conservation Reserve Program (CRP) acres. Researchers noted the buffer was easy to install with a simple, three-compartment design to manage water levels through heavy rains and drought conditions. University trials show 30% to 85% of nitrate reduction in diverted drainage water, and up to 20% phosphorus removal.
Illinois Director of Agriculture Jerry Costello also spoke to attendees and praised the work Illinois Farm Bureau and the McLean County Farm Bureau do in working with the Illinois Department of Agriculture and Illinois Environmental Protection Agency on the Nutrient Loss Reduction Strategy (NLRS).
“Illinois Farm Bureau (IFB) has found that investing in the science and promoting in-field and edge-of-field practices that improve water quality make a big difference downstream,” said Lauren Lurkins, IFB director of environmental policy.
“The city of Bloomington partners with agriculture in many ways to keep drinking water clean, and we also pair with the university research community to find answers. There has to be that connection.”
To read more about IFB’s nutrient stewardship field days, visit www.ilfb.org/fielddays.