Research Projects

2026

A Coordinated Effort to Update Corn N-Fertilizer and Manure Timing Information
Investigators:
Sotirios Archontoulis, Daniel Anderson, Michael Castellano, Richard Roth, Mark Licht, Chad Hart, Mitch Baum, Leah Ten Napel, Rod Williamson
Advanced Assessment of Multipurpose Grassed Waterways
Investigators:
Matthew Streeter, Keith Schilling, Elliot Anderson, Thomas Doyle
An Easy-To-Use Web-Based Decision Support Tool to Optimize When Cereal Rye is Terminated Before Corn Based on Predictions of Corn Yield Loss
Investigators:
Alison Robertson, Rashelle Matthiesen
Assessing Changes in Crop Insurance to Promote the Removal from Production of Cropped Land Subfields that are Low Yielding, Generate Low Market Returns and Cause Environmental Harm
Investigators:
David Hennessy, John Lawrence, Chad Hart, Edward Osei, Philip Gassman, Michael Castellano
Balancing Perenniality with Reality: What are the Holistic, Field-Scale Effects of Multiple Perennial Approaches to Water Quality?
Investigators:
Marshall McDaniel, Reid Barker, Hyeonji Song, Bin Prng, Andy Vanloocke
Can Conservation Agronomists Move the Needle? Examining the Potential Strengths and Weaknesses of Private-Sector Conservation Technical Assistance for Working Lands
Investigators:
J. Arbuckle, Oliver Nell
Closing the Gap in Nutrient Reduction: How Land Tenure, Farm Structure, and Incentives Shape Conservation Adoption in Iowa
Investigators:
Rabail Chandio
Development and Validation of an Integrated Soil Nitrate Decision Support Framework for Predictive Nitrogen Management in Iowa
Investigators:
Richard Roth, Michael Castellano, Sotirios Archontoulis, Mitch Baum, Larousse Dorissant, Aaron Sassman
Field Validation of Low-Cost, In-Situ Soil Nitrogen Sensors for Quantifying Nitrogen Loss Reduction in Manure-Amended Croplands Managed with Cover Crops and Strip Tillage
Investigators:
Jonathan C. Claussen, Michelle L. Soupir, Carmen L. Gomes, Sara K. McMillan
Forecasting Iowa’s Nitrate: A Statewide Database and Weather-Whiplash Framework for the Nutrient Reduction Strategy
Investigators:
Amy Burgin, Terry Loecke, Lien Tran, Marty St. Clair
Understanding the Roles of Key Influencers in Farmer and Landowner Conservation Practice Decision-Making: A Mixed-Method Study of Operators/Non-Operating Landowners, Ag Retailers, and Conservation Agronomists
Investigators:
Erin Heiden, Kyle Endres

2025

Optimizing Planting Methods for Cover Crops Before Corn: Comparison of Precision Planting and Strip Tillage to Achieve Nutrient Loss Reduction and Maintain Yield
Investigators:
Alison Robertson, Rashelle Matthiesen, Peter O'Brien
Accelerating Farmer Adoption of Edge-of-Field Conservation Practices on Leakiest Fields: Economic Experiment Evidence that Reduces Hypothetical Bias
Investigators:
Jacqueline Comito, Wendong Zhang, Cathy Kling
Building Resources for Integrated Decision-making for aGricultural Engagement (BRIDGE)
Investigators:
Linda Shenk, Rick Cruse, Sara McMillan, Ethan Thies
Effect of Winter Cereal Rye Cultivar Selection and Herbicide Choice on Seedling Disease, Pathogen Populations, Nitrogen Dynamics and Growth and Yield of Corn - Year 3
Investigators:
Alison Robertson, Marshall McDaniel, Silvina Arias, Meaghan Anderson
Enhancing In-Season Nitrogen Management in Corn Using UAS-based Remote Sensing and Soil Data Integration
Investigators:
Richard Roth, Beth Reynolds, David Bruene, Logan Wallace
Evaluating Phosphorus Retention in Saturated Riparian Buffers
Investigators:
Wenjuan Huang, Tom Isenhart, Gabriel Johnson, Bill Crumpton
Evaluating Poultry Manure Application Timing and Cover Crops to Maximize Water Quality Benefits in Corn and Soy while Minimizing Cover Crop Yield Drag
Investigators:
Dan Andersen, Michelle Soupir, Sara McMillan
Legacy Phosphorus Storage and Remobilization in a Dynamic Floodplain
Investigators:
Peter L. Moore, Sara W. McMillan, Thomas Isenhart
Making Prairie Practical: Expanding Flexibility in Planting Methods for Retired Marginal Lands and Edge-of-field Nutrient Reduction Practices
Investigators:
Laura Jackson, Justin Meissen
Making Woodchip Bioreactors More Accessible by Expanding Woodchip Source Materials and Increasing Supply Chain Capacity
Investigators:
Jacqueline Comito, Billy Beck, Michelle Soupir
Quantifying Organic Nitrogen and Other Suspended Solids at High Resolutions to Investigate Nutrient Transport Patterns in Iowa Rivers
Investigators:
Elliot Anderson, Keith Schilling, Martin St. Clair
Uncovering Soil and Sediment Properties to Inform Saturated Buffer Design
Investigators:
Tom Isenhart, Keith Schilling, Gabriel Johnson, Matthew Streeter, Jennifer Merryman

2024

Evaluating Manure Application and Cover Crop Planting Timing to Maximize Water Quality Benefits in Corn
Investigators:
Daniel Andersen, Iowa State University
How Long Will Corncobs Improve Nitrogen Removal in Bioreactors?
Investigators:
Michelle Soupir, Iowa State University
Incentivizing Conservation: Understanding Opportunities and Barriers That Influence Iowa Farmers’ Decisions to Adopt Nutrient Management Conservation Practices Over Time
Investigators:
Chris Morris, Iowa State University, J. Arbuckle, Iowa State University
Investigating Long-term Nutrient Trends and Short-term Orthophosphate Dynamics in a HUC12 Basin with Extensive Land Use Change
Investigators:
Elliot Anderson, Iowa Geological Survey, Keith Schilling, Iowa Geological Survey , Ken Wacha, United States Department of Agriculture
Investigating the Fate of Nitrogen Fertilizer in Perennial Groundcover Corn Cropping Systems Using 15N Stable Isotope Labeling
Investigators:
Richard Roth, Iowa State University, Raj Raman, Iowa State University, Ken Moore, Iowa State University
Quantifying Nutrient Load Reduction Practices at Multiple Field Sites
Investigators:
Keith Schilling, Iowa Geological Survey
Rural Iowa Communities' Water Quality Awareness, Engagement and Policy Preferences
Investigators:
Katherine Dentzman, Iowa State University , J. Arbuckle, Iowa State University
Two-stage Agricultural Channels in Iowa's Drained Landsape to Improve Water Quality and Long-term Resilience
Investigators:
Sara Winnike McMillan, Iowa State University, Antonio Arenas, Iowa State University, Peter Moore, Iowa State University , Keith Schilling, Iowa Geological Survey, Johnathon Swanson, Polk County Conservation , Amanda Brown, Polk County Conservation
Watershed Scaling Effects Measured Via Nested High Frequency Sensors
Investigators:
Marty St. Clair, University of Iowa

2023

An integrated assessment framework to evaluate conservation practices and environmental and economic benefits: A case for central Iowa
Investigators:
Phillip Gassman, Tássia Mattos Brighenti , Yongjie Ji
Can adjustments to nitrogen rates reduce corn yield drag and disease implications following a cereal rye cover crop? 2023
Investigators:
Mark Licht, Marshall McDaniel, Alison Robertson, Fernando Marcos, Rashelle Matthiesen, Peter O’Brien
Co-benefits and possible unintended consequences of restoring wetlands for nutrient reduction
Investigators:
Charlie Loewen
Decoding and leveraging the farmer messenger effect to accelerate the adoption of critical edge-of-field conservation practices
Investigators:
Jacqueline Comito, Wendong Zhang
Effect of winter cereal rye cultivar selection and herbicide choice on seedling disease, pathogen populations, nitrogen dynamics and growth and yield of corn
Investigators:
Alison Robertson
Equipping conservation practitioners with quantitative estimations of sediment and P reduction from BMPs
Investigators:
Eduardo Luquin, Emily Zimmerman, Brian Gelder, Daryl Herzmann, Richard Cruse
IIHR water quality research plan
Investigators:
Marty St. Clair
Linking agricultural practices to water quality improvement: The importance of spatial scale in accurately characterizing nonpoint source nutrient loads in Iowa stream systems
Investigators:
David Green, William Crumpton, Sara McMillan, Tom Isenhart, Peter Moore
Quantifying nutrient load reduction practices and export at field and landscape scales
Investigators:
Keith Schilling, Matthew Streeter, Elliot Anderson, Joe Honings

2022

Assessing the effectiveness of spatial and temporal separation of a cereal rye cover crop from corn on nutrient reduction and corn yield.
Investigators:
Alison Robertson , Rashelle Matthiesen, Peter L. O’Brien
Benefits of winter cereal rye cultivar selection in mitigating corn yield drag
Investigators:
Alison Robertson , Jyotsna Acharya
Evaluating the effectiveness of stacked practices: Utilizing modified blind inlets at terrace sites for N and P load reductions
Investigators:
Matthew Streeter , Keith Schilling
Evaluating the relation of phosphorus to turbidity during high flow events in western Iowa rivers to improve phosphorus load estimates
Investigators:
Keith Schilling
Extending saturated buffers to additional landscape positions
Investigators:
Tom Isenhart , Keith Schilling
IIHR Hydroscience and Engineering Work plan (2022-2023)
Investigators:
Chris Jones
Landowners matter too: Accelerating adoption of in-field and edge-of-field nutrient reduction practices through better-engaged landowners
Investigators:
Chad Hart , Wendong Zhang
Quantifying co-benefits of water quality conservation practices for wildlife of greatest conservation need in Iowa
Investigators:
Adam Janke, Emily Zimmerman, Karen Kinkead, Tyler Harms
Sociological water quality research: quantifying factors at multiple scales that influence farmers to shift from being potential to actual adopters of conservation practices
Investigators:
Suraj Upadhaya , J. Arbuckle, Lisa Schulte Moore