Search results

Pothole "hotspot" research
Practice: 
Nutrient Management

Title:  Quantifying hotspots of nitrate and dissolved phosphorus losses from cropped depressions and their impacts at the catchment scale

Location:  Story, Boone, Palo Alto Counties

Time Period:  2018-present

Research Team:  Steven Hall, Bill Crumpton, and Matt Helmers

Project Description:  Improving our understanding of the spatial distribution of “hotspots” for nitrate and phosphorus loading to surface water provides a key opportunity for informing strategic management interventions and their potential for improving regional water quality. Drained and cropped depressions (former prairie pothole wetlands) under corn and soybean cultivation often experience intermittent flooding and crop mortality. Our preliminary data show that these depressions represent likely hotspots for hydrologic nutrient losses that contribute disproportionately to nutrient losses at the field scale. Targeting these hotspots could enable an efficient strategy for nutrient reduction with lower impacts to farm operations. We will quantify the importance of depressions vs. uplands to field- and catchment-scale nutrient loading under traditional management, and in fields with cover crops.

Publications: 

Funders:  Iowa Nutrient Research Center, EPA, USDA

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

Wartershed monitoring site
Practice: 
Multi-Objective

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. 

Iowa landscape
Practice: 
Multi-Objective

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

Iowa landscape
Practice: 
Multi-Objective

Title:  The Iowa Nutrient Reduction Strategy Farmer Survey project

Location:  Statewide

Time Period:  2015-present

Research Team: J. Arbuckle, Zhengyuan Zhu, and Laurie Nowatzke

Project Description:  The Iowa Nutrient Reduction Strategy Farmer Survey project, a five-year (2015-2019) farmer survey that is: (1) measuring farmer knowledge, attitudes, and behavior related to nutrient management and nutrient loss into waterways, (2) identifying barriers to and facilitators of behavior change that reduces nutrient loss, and (3) measuring changes in these over time.

Publications:

https://store.extension.iastate.edu/product/15707

https://store.extension.iastate.edu/product/15507

https://lib.dr.iastate.edu/stat_las_pubs/153/

Funders:  Iowa Nutrient Research Center, IDALS, Iowa State University Extension

Gully erosion at Neal Smith National Wildlife Refuge
Practice: 
Nutrient Management

Title:  Phosphorus loss from ephemeral gully formation and sediment transport

Location:  Neal Smith National Wildlife Refuge

Time Period:  2015

Research Team:  Richard Cruse, Eric Hurley, Antonio Mallarino, and Matt Helmers

Project Description:  Project goal was to determine the quantity of phosphorus loss in 12 Iowa watersheds and the proportion of total phosphorus loss from these watersheds that originates from ephemeral gully formation.  In watersheds with 100% rowcrop, approximately 50% of total phosphorus loss was ephemeral gully sourced. The contribution of phosphorus loss from ephemeral gullies is reduced by an average of 50% in watersheds that contain perennial cover in strategic locations reducing ephemeral gully formation. Average loss of water soluble phosphorus from ephemeral gullies was also reduced by 40% when perennial grasses were strategically placed reducing ephemeral gully formation.  

A second task of this grant was to define a mapping procedure to delineate permanent vegetation along streams that represents the riparian zone. Automated methods using imagery, NDVI and proximity to streams generated vegetation polygons far beyond the riparian zone especially in more forested areas of the state. Ancillary data such as alluvial soils and landscape position were tested to see if they improved the riparian designation. Alluvial soils were shown to be helpful but the process still required a staff person to review the preliminary results and make data modifications. This process proved faster than manual digitizing and provided more repeatable and consistent results however, it required good resolution spring CIR imagery.

About a year after this portion of the project was completed, QA/QC conservation practice data was made available for public download as it was reviewed and finalized at https://www.gis.iastate.edu/gisf/projects/conservation-practices. The entire statewide dataset was finally completed and online in May 2019.

Publications:

Funders:  Iowa Nutrient Research Center, NIFA and Iowa State University Department of Agronomy

 

Iowa landscape
Practice: 
Nutrient Management

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

Emerging cover crops at ISU research farm
Practice: 
Land Management

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. 

COBS site in Boone County
Practice: 
Nutrient Management

Title:  Comparison of Biofuel Cropping Systems (COBS)

Location:  Boone

Time Period:  2008-present

Research Team:  Michael Thompson, Matt Helmers, Matt Liebman, and Robert Horton

Project Description:  The experiment is large-scale (24 plots, each 27 m x 61 m, four replications of each system) and compares biomass production, fossil fuel replacement value, and environmental impacts for continuous corn grown for grain and stover removal with (CCW) and without (CC) a rye cover crop; multi-species perennial crops grown for aboveground biomass with (PF) and without (P) fertilizer; and a conventional corn-soybean grain system, used as a comparison baseline.

Twelve aluminum culverts were buried vertically at the ends of the center drainage lines from pairs of individual plots. Drainage lines from the plots are directed to sumps in the culvert, and drainage is pumped through plastic plumbing fitted with a plated sprayer nozzle and a water meter. Back pressure created by the meter forces a constant fraction (~0.25%) of all drainage to be diverted to a 10-L sampling bottle. The in-line flow meter is read when water samples are taken, and the system is also set up for continuous logging of the flow meters through switch-closure logging. This configuration provides the infrastructure for continuously monitored flow-volume measurements and flow-integrated sampling of subsurface drainage from each plot.

Drainage water samples have been collected weekly from the outlets of each plot during flow periods. Concentrations and loads of nitrate (NO3-N) and phosphate (PO4-P) were determined. Drainage water samples collected from the PF and P cropping systems had the lowest flow weighted mean concentration and load of NO3-N, which means the prairie cropping systems substantially limited the leaching of NO3-N even when the prairie received nitrogen fertilizers. Additionally, the continuous corn system with cover crops had lower nitrate-N concentration and load than the continuous corn system with no cover crop. Overall, the mass loss of PO4-P is quite low -- less than 0.14 kg/ha for all treatments.

Publications:  Daigh, A.L.M., U. Ghosh, J. DeJong-Hughes, and R. Horton. 2018. Spatial response of near-surface soil water contents to newly imposed soil management. Agric. Environ. Lett. 3:180032. doi:10.2134/ael2018.06.0032.

Daigh, Aaron L. M., Xiaobo Zhou, Matthew J. Helmers, Carl H. Pederson, Robert Horton, Meghann Jarchow and Matt Liebman. 2015. Subsurface drainage nitrate and total reactive phosphorus losses in bioenergy-based prairies and corn systems. Journal of Environmental Quality 44:1638-1646.

Funders:  Leopold Center for Sustainable Agriculture, Iowa Nutrient Research Center, Agronomy Department, ISU, College of Agriculture and Life Sciences, ISU

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

Spatial planting arrangement of a winter cereal rye cover crop
Practice: 
Land Management

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. 

Strip tillage with rye cover crop
Practice: 
Nutrient Management

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. 

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