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Title:  Black Hawk Lake watershed NWQI monitoring

Location:  Nearest centrally located town is Carnavon, IA

Time Period:  2014-2019 (Phase I), 2020-2024 (Phase II)

Research Team:  Michelle L. Soupir, Matthew Helmers, Amy Kaleita, Leigh Ann Long, Ji Yeow Law, Allen Bonini, Jason Palmer, T.J. Lynn, and Ethan Thies

Project Description:  Water quality monitoring (nitrogen, phosphorus, sediment, and bacteria) is conducted in several smaller subwatersheds of the larger Black Hawk Lake watershed from March-November. The monitoring data are being used to determine if pollutant load reduction strategies, including grass waterways, terraces, cover crops, CRP – native grass plantings, CREP wetlands, reduced tillage, and nutrient management plans, are effective in different subwatersheds with various levels of BMP implementation, ranging in areal coverage from 20% to 88%. In the monitored subwatersheds, both surface outlets and tile outlets are monitored during baseflow and storm events to capture the total outflows from these subwatersheds.

Publications:  Brendel, Conrad. 2017. Evaluation of subsurface drainage on phosphorus losses and application of the SoilIceDB model in the Black Hawk Lake Watershed, Iowa. M.S. thesis, Iowa State University.

Brendel, Conrad E., Michelle L. Soupir, Leigh Ann M. Long, Matthew J. Helmers, Charles D. Ikenberry, and Amy L. Kaleita. 2018. Catchment-scale phosphorus export through surface and drainage pathways.  Journal of Environmental Quality 48 (1):117-126.  doi:10.2134/jeq2018.07.0265.

Law, Ji Yeow, Conrad Brendel, Leigh Ann Long, Matthew Helmers, Amy Kaleita, Michelle Soupir (submitted). Impact of land use changes and conservation practices on phosphorus and sediment export at the catchment scale. Journal of Environmental Quality.

Neher, Timothy P. 2019. Catchment-scale export of antibiotic resistance genes and bacteria from an agricultural watershed in central Iowa. M.S. thesis, Iowa State University.

Neher, Timothy P., Lanying Ma, Thomas B. Moorman, Adina C. Howe, and Michelle L. Soupir. 2020. Catchment-scale export of antibiotic resistance genes and bacteria from an agricultural watershed in central Iowa.  PLoS ONE 15(1):e0227136. https://doi.org/10.1371/journal.pone.0227136.

Van der Woude, Katherine. 2018. An analysis of BMPs and their combined effectiveness at reducing nitrate-nitrogen export to the Black Hawk Lake Watershed, Iowa. M.S. thesis, Iowa State University.

Funders:  National Water Quality Initiative - US EPA Region 7, Section 319; Iowa Department of Natural Resources; USDA

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits. 

Title:  Increasing farmer engagement with conservation practices through more effective communication strategies: A media content analysis, stakeholder survey, and digital message test

Location:  Statewide

Time Period:  2019-2021

Research Team:  Laura Witzling, Dara Wald, and Jacqueline Comito

Project Description:  “Increasing farmer engagement with conservation practices through more effective communication strategies: A media content analysis, stakeholder survey, and digital message test” is a collaboration between the Iowa Learning Farms and communication researchers at Iowa State University in the Greenlee School of Journalism and Communication. The long-term objective of the project is to grow current farmer and landowner engagement in conservation practices. Organizations like the Iowa Learning Farms have taken steps to engage farmers, but more work is needed to amplify such efforts and to call attention to a greater diversity of conservation options, and to younger and female farmers and landowners. In order grow engagement, project partners will first evaluate existing messages about conservation and barriers to conservation action designed to minimize nutrient loss. The content analysis will include messages that appear in agricultural news media publications and messages that appear in media produced by key farmer organizations. Using transcripts from interviews with farmers, messages produced by farmers themselves will also be analyzed. Next, Iowa farmers and landowners will be surveyed in order to better understand their perspectives on conservation practices and communication preferences. Lastly, project partners will take what they’ve learned from the content analysis and survey and create different messages promoting online resources about conservation and a field day (an educational event where farmers can learn about different conservation practices) on social media. The messages will be evaluated based on their ability to generate clicks and attendance at the field day. Project partners expect that this project will ultimately result in more effective message strategies for engaging farmer audiences in conservation practices aimed at reducing surface water nutrient loss, and more effective message strategies for engaging farmers in less popular conservation practices aimed at reducing surface water nutrient loss.

Publications:

Funders:  Iowa Nutrient Research Center

Title:  Mitigating reduced yields of corn following a winter rye cover crop: what role does allelopathy play?

Location:  Iowa State Campus

Time Period:  2019 -2020

Research Team:  Alison Robertson

Project Description:  Environmental benefits associated with growing cover crops (CC) are well documented. In Iowa, winter rye is the most extensively used CC. In some years and fields, however, corn yield decreases have been reported following winter rye CCs, consequently, many corn producers are hesitant to try CCs. Potential causes of this yield decline include allelopathy and planting issues. We demonstrated winter rye serves as a green bridge for soil-borne pathogens of corn and seedling disease may also play a role in yield decline. However, seedling disease cannot solely be blamed. We hypothesize that allelopathy may also play a role in yield decreases of corn in the winter rye-corn production system. Winter rye produces numerous allelopathic compounds that may affect corn growth and development, and the soil microbial community, including plant pathogens. The persistence, availability and activity of allelochemicals is influenced by a range of biotic and abiotic factors. We are curious if allelopathy could explain why corn yield decreases occur in some fields but not others. The central hypothesis of our proposed project is when corn is planted into rye residue, corn growth is stunted and seedling roots more rotted because rye allelochemicals enhance seedling disease caused by Pythium spp. This proof of concept study will provide (i) data regarding the interaction of allelopathic compounds and corn seedling pathogens in a lab-based assay. If an interaction is detected, the data will inform further research in this area.

Publications:

Funders:  Iowa Nutrient Research Center

Title:  Improving cereal rye cover crop BMPs to increase adoption of cover crops by Iowa farmers

Location:  Iowa State University Ag Engineering and Agronomy Farm, Boone, Iowa State University Northwest Research Farm, Iowa State University South East Research Farm

Time Period:  2018-2020

Research Team:  Alison Robertson, Mark Licht, J. Arbuckle, Mike Castellano, Liang Dong, Bob Hartzler, Erin Hodgson, Andy Lenssen, Marshall McDaniel, Tom Moorman and Alejandro Plastina

Project Description:

Issue: The Iowa Nutrient Reduction Strategy (INRS) calls for cover crop implementation on over 12 million acres, which equates to every other field. Despite numerous environmental benefits associated with cover crops, many farmers are still hesitant to change their current production practices. Major barriers to introducing cover crops as a conservation practice include cost of implementation, yield drag, and knowledge. This multi-disciplinary team will address the barriers of using cover crops and develop best management practices (BMPs) for including a cover crop in a corn-soybean production system in Iowa for “hesitant” farmers. Using these data, we will develop a set of BMPs with a partial cost budget to encourage farmers to include cover crops in corn-soybean production systems, and therefore meet the INRS goals of cover crop acreage adoption in Iowa.

Objective: This research will evaluate the effect of cover crop seeding rate, seeding method, and termination timing on corn production, soil health and nutrient recycling. Treatment effects on (i) cover crop and corn growth and development (ii) weed, pest and disease pressure, (iii) nutrient recycling, and (iv) soil health will be assessed. In addition, partial budgets for treatments will be developed and Iowa farmers surveyed to identify common methods of seeding cover crops users and perceived efficacy of those methods.

Publications:

Funders:  Iowa Nutrient Research Center

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits. 

Title:  Influence of spatial planting arrangement of a winter cereal rye cover crop on corn productivity

Location:  Iowa State University Ag Engineering and Agronomy Farm, Boone

Time Period:  2018-2020

Research Team:  Alison Robertson, Tom Moorman and Andy Lenssen

Project Description: 

Issue: Winter cover crops have the potential to recycle nutrients, reduce nutrient contamination of surface waters, improve soil health, and increase the sustainability and resilience of our agricultural landscapes. Winter rye is one of the most widely used and successful cover crops in the Upper Midwest, but many farmers are reluctant to try winter rye for various reasons. Although soybean yield following a rye cover crop is usually the same or greater than without a cover crop, there have been reports of possible corn yield reductions following a rye cover crop. Winter rye is a known host of corn seedling pathogens and these pathogens can increase while the rye is dying.  Under cold and wet weather conditions, seedling disease may reduce stands or reduce the vigor of corn planted after winter rye.  Our previous research has shown that increasing the time between rye termination and corn planting reduces this. Additionally, our new preliminary research suggests that the closer corn is planted to the rye crown and the roots originating from it, the greater the chance it will be infected by pathogens from the dying rye resulting in seedling disease. New advancements in precision planting and guidance make controlling the spacing of rye cover crop plants and the following corn row feasible on a field scale.

Objective: This research will evaluate the effect of the proximity of winter rye crowns to corn growth and development with a view to improve our understanding of yield decline that may occur in corn planted after rye. We will examine treatment effects on (i) corn growth and development throughout the growing season, and yield, (ii) seedling disease and stalk rot development, and (iii) N recycling.

Publications:  Kurtz, S.M., Acharya, J.A., Kaspar, T.C., Moorman, T. and Robertson, A.E. 2019. Does the proximity of corn seedlings to terminated winter rye affect seedling disease development caused by Pythium species? (Abstr.). Phytopathology 109.S2.139.

Funders:  Iowa Nutrient Research Center and NC-SARE

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits. 

Title:  Corn management following cereal rye cover crop with strip tillage and in-row fertilization

Location:  Iowa State University Farms: Ames and Kanawha

Time Period:  2019 - 2021

Research Team:  Mark Licht, Alison Robertson, Bob Hartzler, Erin Hodgson, and Andy Lenssen

Project Description:  Cover crops are a conservation practice that can have tremendous benefits for improving soil health and reducing nutrient losses. There is limited research available on management practices that provide farmers information to facilitate cover crop adoption and minimize potential yield limiting factors. Our project evaluates the effects of a winter rye cover crop-free zone through the use of strip-tillage and starter fertilizer to improve seedling vigor and eliminate yield drag associated with winter cereal rye. This objective will be reached by elucidating treatment effects on: 1) corn growth and development throughout the growing season; 2) disease, insect and weed incidence, severity, and prevalence; and 3) winter cereal rye biomass growth and nutrient uptake. This study will be conducted at the ISU Agricultural Engineering and Agronomy Farm (AEA) and one outlying research farm. Experimental treatments will consist of two tillage systems (strip-tillage and no-tillage) and three starter N fertilizer rates. Cover crops will be seeded in the fall into soybean. Cover crops will be terminated 10-14 days ahead of corn planting for all treatments as per current recommendations. Cover crop and corn crop growth and development parameters will be collected throughout the respective life cycles. Corn seedling roots will be evaluated for root rots. Insect incidence and weed density/community notes will be determined.

Publications:

Funders:  Iowa Nutrient Research Center

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits. 

Title:  Interseeding grass and legume cover crops into early vegetative stage corn

Location:  To be determined

Time-Period:  2020-2022

Research Team:  Mark Licht, Micheal Witt, Angie Rieck-Hinz, and Md. Rasel Parvej

Project Description:  Three main areas of cover crop interseeding (cover crop species selection, establishment timing, and seeding method) need further research to understand how they interact with modern corn hybrids under Iowa climate and soil conditions. Further exploration of these factors will fill a knowledge gap to guide best management practices for interseeding cover crops into a corn cash crop. This project will develop best management practices for interseeding cover crops into a corn cash crop. Our objective is to evaluate the effects of interseeded cover crop species, establishment timing, and seeding method on corn productivity. This objective will help clarify treatment effects on: (1) cover crop establishment, biomass accumulation and nutrient uptake; (2) corn growth, productivity, and nutrient uptake; and (3) weed community and diversity. A comprehensive field study will be conducted at the ISU Northwest Research and Demonstration Farm, Sutherland, IA and the Armstrong Research and Demonstration Farm, Lewis, IA. Three cover crop species will be used (winter rye, annual rye grass, and red clover) with three establishment timings (V3, V5, and V8) and two seeding methods (drilled or broadcast). Crop growth and development, nutrient uptake, crop reflectance, and grain yield will be evaluated. We will conduct 5 to 10 on-farm trials utilizing a sub-set of the treatments from the research farm trials that match the farmers’ interests and/or abilities. The on-farm trials will compare no interseeding with 1 or 2 additional treatments in a replicated strip trial design throughout the field. Crop growth and grain yield will be evaluated.

Publications:

Funders:  Iowa Nutrient Research Center

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits. 

Title:  Evaluating rotations of cover crops and summer annual forages for yield, nutritional value, effect on soil nutrient profile, and economic sustainability as forage resources for beef cattle

Location:  Armstrong Research Farm, Lewis, IA.  Neely-Kinyon Farm, Greenfield, IA.  McNay Research Farm, Chariton, IA

Time Period:  2019-2023

Research Team:  Chris Clark, Erika Lundy, Patrick Wall, and Aaron Saeugling

Project Description:  Researchers are using replicated forage test plots on southern Iowa research farms to provide beef producers with research-based information on cool season and warm season annual forage feeding value, expected yields, and impact on soil nutrient profile.  The study began with baseline soil samples and seeding of summer annuals in summer of 2019.  Crop rotation will consist of summer annual forage species such as pearl millet, sorghum-sudangrass, and forage sorghum followed by fall-seeded winter cover crop species such as cereal rye, triticale, and winter wheat.  Forage samples will be collected to be tested for nutrient content, which will be used to determine feeding value and to calculate estimated soil nutrient removal with forage harvest.  Small strips of forage will also be harvested for yield estimates. Soil samples were collected and tested for phosphorus, potassium, pH, and OM prior to plot establishment. Samples will also be taken upon conclusion of the study to evaluate changes in soil nutrient profile and organic matter that may have developed over the course of the study. ISU Extension Beef and Agronomy specialists will cooperate to collect and analyze data and share results through a variety of methods. The forage test plots are anticipated to be used at each of the ISU outlying farms as demonstration resources throughout the growing season including new and existing ISUEO forage related programs such as Greenhorn Grazing, Southwest Iowa Pasture Clinics, and the annual McNay Fall Field Day. Outreach materials may also include newsletter articles from the Iowa Beef Center and the agronomy team and presentations at various ISU Extension programs.  At the conclusion of the study, a research report will be generated highlighting the data collected as well as the challenges and opportunities identified in the project.  

Publications: 

Funders:  Iowa Nutrient Research Center, Southern Iowa Forage and Livestock Committee

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits. 

Title:  Corn cobs as an alternative carbon source to enhance bioreactor performance for improved water quality

Location:  Iowa State University Ag Engineering and Agronomy Farm, Boone, IA

Time Period:  2018-2020

Research Team:  Michelle Soupir, Ji Yeow Law, Thomas Isenhart, Morgan Davis, Natasha Hoover, and Alexis Slade

Project Description:  In 2018, the six of the nine pilot-scale bioreactors at the Experimental Tile Drainage Denitrification Bioreactors site were modified with the addition of corncobs. Woodchips were excavated from the inlet end ¼ of three bioreactors and ¾ of another three bioreactors, then refilled with corncobs. The study will focus on differences in nitrate (NO₃-N) removal with the more readily available carbon provided by the corn cobs and changes in microbial communities, as well as a techno-economic analysis (TEA) evaluating the feasibility of corncobs as a replacement for the current go to fill material of woodchips.   

Publications: 

Funders:  Iowa Nutrient Research Center , Green Products Company

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits. 

Title:  Woodchip bioreactors for improved water quality

Location:  Iowa State University Ag Engineering and Agronomy Farm, Boone, IA

Time Period:  2017-2018

Research Team:  Michelle Soupir, Natasha Hoover, Thomas Moorman, Thomas Isenhart, Morgan Davis and Emily Martin

Project Description:  This research was completed at the pilot-scale bioreactor system that was installed in 2014, and focused on building on the knowledge of kinetics and mechanisms for nitrate removal in woodchip bioreactors and identified flow conditions that may contribute to potential negative impacts such incomplete denitrification resulting in potential greenhouse gas emissions. Analysis and evaluation of the results of this study are ongoing, and will continue to add to the body of knowledge about woodchip bioreactors.  

Publications:  Davis, M.P., E.A. Martin, T.B. Moorman, T.M. Isenhart, M.L. Soupir. 2019. Nitrous Oxide and Methane Production from Denitrifying Woodchip Bioreactors at Three Hydraulic Residence Times. Journal of Environmental Management 242: 290-297.

Martin, E.A., M.P. Davis, T.B. Moorman, T.M. Isenhart, M.L. Soupir. 2019. Impact of hydraulic residence time on nitrate removal in pilot-scale woodchip bioreactors. Journal of Environmental Management, 237: 424-432.

Funders:  Iowa Nutrient Research Center

Disclaimer:  This is an active research site, please contact the research team prior to planning any site visits.