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Title: Evaluating the potential for drainageways at the Kirkwood Community College farm to serve as test sites for innovative grass waterway designs

Location: Kirkwood Community College, Cedar Rapids, IA

Time Period: 2019 - 2021

Research Team: Keith Schilling, and Matthew Streeter

Project Description: In this project we evaluated the subsurface soils and hydrogeology found in two grass waterways complexes in eastern Iowa and assessed the potential for nitrate processing to occur in these lowland drainageways. Using data obtained from a network of 12 shallow wells installed across six different waterways, we found that the waterways contained fine-textured and nutrient rich alluvial soils derived from erosion and deposition of upland loess and till. Strong circumstantial evidence, including a high water table, abundant organic carbon, anaerobic conditions, and an ongoing nitrogen source, suggested that conditions within the waterways were conducive for denitrification to occur. We compared groundwater patterns in the waterways to concurrent monitoring in nearby upland cropped fields and found that NO3-N concentrations in waterway groundwater (3.1 mg/l) were 70% lower compared to groundwater beneath nearby cropped fields (10.5 mg/l). Since most grass waterways are tiled, we envision a new “saturated waterway” design that would allow waterway tiles to reconnect upland groundwater to the organic-rich drainageway deposits for NO3-N reduction.

Publications:

Funders: Iowa Nutrient Research Center, complimentary funding from the Iowa Pork Producers Association started 9/1/21.

Disclaimer: This is an active research site; please contact Keith Schilling (keith-schilling@uiowa.edu) prior to planning any site visits.

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 online. 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

Title:  Development of remote sensing protocols for inventory of nutrient management practices: Permanent vegetative practices

Location:  Statewide in 40 WQI HUC 12s

Time Period:  2014 -2016

Research Team:  Robin McNeely, Jim Giglierano, Amy Logan, Sarah Porter, David James, Thomas Isenhart, and Calvin Wolter

Project Description:  This grant funded the initial work for what evolved into the statewide conservation practices inventory mapping project that spanned four years and multiple funding sources. The proposal for this grant aimed to create a GIS dataset of permanent vegetative practices in three pilot HUC 12s using semi-automated software processes with existing landcover data and newly collected imagery. After testing the procedure, it was determined that the results were not satisfactory without human interpretation and editing. The project evolved to using ISU and DNR staff to manually find six vegetative and structural practices in 40 IWQI HUC 12s. Student interns visually identified and digitized conservation practices using aerial imagery and LiDAR-derived products such as hillshade and slope. Hillshade provides a three-dimensional view of the ground to supplement the natural color and infrared aerial photography.  The conservation practices were collected as line and polygon features in a GIS dataset.

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 online. The entire statewide dataset was finally completed and online in May 2019.

Publications:

Funders:  This portion of the statewide project was funded by the INRC.  The entire four year statewide project was additionally funded by the IDNR, IDALS, INREC, AmericaView and NLAE.

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

Title:  Conservation practices inventory for select Iowa HUC 12 watersheds – Upper, Middle and East Fork Des Moines Rivers

Location:  Upper, Middle and East Fork Des Moines Rivers HUC 8 watersheds in Iowa

Research Team:  Robin McNeely, Josh Obrecht, Calvin Wolter and Adam Schnieders, and IDNR

Project Description:  This project fulfills a priority of the Iowa Nutrient Reduction Strategy by providing a meaningful record of the in-field and off-field conservation practices for reducing erosion and nutrient loss. The State of Iowa has lacked a comprehensive database of practices in each watershed and this project contributed data to that end. Student interns visually identified and digitized six specific NRCS vegetative and structural conservation practices on the landscape using aerial imagery and LiDAR-derived products such as hillshade and slope. Hillshade provides a three-dimensional view of the ground to supplement the natural color and infrared aerial photography.  The conservation practices were collected as line and polygon features in a GIS dataset. After this portion of the project was completed, the statewide dataset was made available for public download online.

Publications:

Funders:  This portion of the statewide project was funded by the Iowa Nutrient Research Center. The entire four year statewide project was additionally funded by the IDNR, IDALS, INREC, AmericaView and NLAE.

Title:  Conservation practices inventory for select Iowa HUC 12 watersheds

Location:  Upper Iowa, Upper Wapsipinicon, Skunk, Maple, Boyer, East and West Nishnabotna, and Upper Chariton HUC 8 watersheds in Iowa

Time Period:  Work was done 6/1/16–6/30/17 but the data collected used imagery from 2008-2010.

Research Team:  Robin McNeely and Josh Obrecht, ISU GIS Facility, Calvin Wolter and Adam Schnieders, and IDNR

Project Description:  This project fulfills a priority of the Iowa Nutrient Reduction Strategy by providing a meaningful record of the in-field and off-field conservation practices for reducing erosion and nutrient loss. The State of Iowa has lacked a comprehensive database of practices in each watershed and this project contributed data to that end. Student interns visually identified and digitized six specific NRCS vegetative and structural conservation practices on the landscape using aerial imagery and LiDAR-derived products such as hillshade and slope. Hillshade provides a three-dimensional view of the ground to supplement the natural color and infrared aerial photography.  The conservation practices were collected as line and polygon features in a GIS dataset. The funding from this grant allowed for data collection in 98 of the 293 HUC 12s contained by the HUC 8s listed in the location.  After this portion of the project was completed and reviewed by DNR staff, the statewide dataset was made available for public download online.

Publications: 

Funders:  This portion of the statewide project was funded by the INRC.  The entire four year statewide project was additionally funded by the IDNR, IDALS, INREC, AmericaView and NLAE.

Title: Furthering our understanding of the interaction of cereal rye allelochemicals with Pythium species and their impact on corn in the cereal rye-corn production system

Location: Iowa State University Campus

Time Period: 2021 - Present

Research Team: Alison Robertson and Jyotsna Acharya

Project Description: The most prevalent cover crop used in the corn-soybean production system in Iowa is cereal rye (CR). Management of CR in field crop production system continues to evolve, for example, some farmers are growing CR longer (planting corn into standing green rye) to get more biomass and greater ecosystem services. However, there are challenges associated with greater CR biomass production including reduced corn growth and yield. Proposed reasons for this yield decline in corn are seedling disease and allelopathy.

We have consistently demonstrated a CR cover crop serves as a green bridge for soil-borne pathogens of corn that cause seedling diseases and yield reductions, and we hypothesize allelopathy may also play a role. Allelopathy is a complex process in which plants release chemical compounds that affect the growth and physiological processes, e.g. defenses, of other plants. Allelochemicals also affect plant-microbiome interactions. Recently, with funding from INRC, we demonstrated synthetic MBOA, an allelochemical produced by CR, and secondary metabolites from CR plants reduced corn shoot and root growth in vitro and caused more severe seedling disease when Pythium was present.

The infective propagules (inoculum) of Pythium are oospores, sporangia, zoospores. Their germination is stimulated by seed and root exudates. We hypothesize allelochemicals released from decomposing rye residue favor germination and/or activity of Pythium in the corn spermosphere facilitating increased infection of the seedling that results in poor vigor and corn yield reductions in the cereal rye-corn production system by favoring seedling pathogen-corn interactions and by affecting early corn growth and development. In controlled studies, we will determine the effect of rye exudates on the (i) germination of oospores and sporangia, and (ii) movement of zoospores of Pythium species, belonging to Clade B and F, in the presence and absence of corn seedling exudates.

Publications:

Acharya, J., Kaspar, T. and Robertson, A.E. 2021. Effect of 6-Methoxy-2-benzoxazolinone (MBOA) on Pythium species and corn seedling growth and disease. Plant Dis. https://doi.org/10.1094/PDIS-04-20-0824-SC

Funders: Iowa Nutrient Research Center

Title: Unlocking the bioreactor microbiome for nutrient management and water quality

Location: Ames

Time Period: 2022- 2024

Research Team: Adina Howe, Steven Hall, Michelle Soupir, Jaejin Lee,  Lindsey Hartfiel

Project Description: Bioreactors have been adopted globally to treat nitrate-laden water. Thus far, research has largely focused on understanding the physical and chemical controls of bioreactor performance (system design, temperature, residence time, etc.), showing that regardless of engineering design, nitrate mass removal rate per unit of carbon source is similar across systems. Thus, it is unlikely that engineering design will transform bioreactor performance. Bioreactors are ‘living’ engineered biological systems, and we argue that improvements in their performance will come from design or management of their carbon source and/or microbiomes. For example, among carbon sources, corncobs have high potential for improved NO3-N removal, especially at low temperatures. Corncobs have been shown to have higher NO3-N removals than woodchips. The microbial communities in bioreactors are also pivotal for driving denitrification and “pollution swapping,” namely the production of greenhouse gases (i.e., methane  and nitrous oxide)  and pollutants (i.e., methylmercury).  In this proposal, we seek to identify and manipulate microbial communities in corncob and woodchip bioreactors that mediate complete denitrification of nitrate to dinitrogen gas, with minimal release of nitrous oxide, methane, or methylmercury to expand the full potential of this conservation practice.

Publications:

Funders: Iowa Nutrient Research Center

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

Title: The effectiveness of carbon credit programs at reducing nutrient losses: An assessment of public and private conservation programs and their interactions

Location: Statewide

Time Period: 2021 -2023

Research Team: Hongli Feng, Sarah Carlson, Paige Leytem Frautschy, Elizabeth Reaves, Lisa Schulte-Moore, Wendong Zhang

Project Description: There have been intense interests in carbon sequestration and greenhouse gas (GHG) emission reduction in the agricultural sectors recently. Meanwhile, there have been decades of efforts and investment to reduce nutrient loss from agriculture. From a policy standpoint, carbon and nutrient reduction are inseparable for to two reasons: (a) most conservation practices that reduce nutrient loss also sequester carbon; and (b) both government and private incentives can be used to support the same set of conservation practices. By investigating these links, our team of cross-disciplinary researchers and non-governmental organization (NGOs) partners will evaluate how carbon credit programs will affect nutrient loss reduction with a focus on farmers’ decision-making regarding program participation.

Publications:

Funders: Iowa Nutrient Research Center

Disclaimer: These are active research sites, please contact Hongli Feng prior to planning any site visits.

Title: Sociological water quality research: quantifying factors at multiple scales that influence farmers to shift from being potential to actual adopters of conservation practices

Practice: Multi-objective

Location: Statewide

Time Period: 2022- 2024

Research Team: Suraj Upadhaya, J. Arbuckle, Lisa Schulte Moore

Project Description: There is an increasing awareness that in-field and edge-of-filed conservation practices in agriculture improve water quality and other ecosystem services, including the reduction of greenhouse gas (GHG) emissions. Although sustaining agricultural productivity at high levels while minimizing nutrient loss is a significant challenge for modern agriculture, farmers' adoption of conservation practices can help mitigate soil degradation and water quality impairment. However, despite decades of major outreach, extension, and conservation endeavors, governmental and non-governmental organizations promoting these voluntary conservation practices still have difficulties getting farmers to adopt them. Most of the existing adoption studies typically measure whether a farmer uses a practice or not. By lumping all non-adopters into a single category, typical adoption studies miss the opportunity to examine potential adopters who may be open to or interested in adopting conservation practices. A better understanding of farmers' conservation practices and adoption behavior is essential to successfully implementing outreach interventions that improve water quality and other ecosystem outputs.

Objective: This project aims to understand which factors influence farmers to shift from potential to actual adopters of conservation practices.

Approach:  We will use data from two high-quality surveys of Iowa farmers, the Iowa Farm and Rural Life Poll (IFRLP) and the Iowa Nutrient Reduction Strategy (INRS) farmer survey, to understand the factors that predict shifts between non-adoption, potential adoption, and actual adoption categories over time. By understanding which factors predict shifts from the potential adopter of conservation practices to the adopter, we will develop a more comprehensive understanding of farmers' adoption processes. We will integrate this understanding into extension and outreach programs to stimulate the higher adoption of conservation practices in Iowa and beyond.

Publications:

Funders: Iowa Nutrient Research Center

Title: Managing crop residue to reduce optimum nitrogen fertilizer inputs and increase yield

Location: Ames, IA

Time Period: 2021 - Present

Research Team: Michael Castellano, Alexandria Logan, and Sotirios Archontoulis

Project Description:  There is growing evidence that the amount of both corn and soybean residue affect the optimum nitrogen fertilizer rate to the following corn crop (i.e, the Maximum Return to Nitrogen or MRTN). In the rainfed Corn Belt, high levels of residue are hypothesized to lead to higher optimum nitrogen fertilizer rates. However, recommended nitrogen fertilizer rates do not consider the amount of residue from the previous crop. This project will determine the ability for farmers to adjust optimum nitrogen fertilizer rates based on the amount of corn and soybean residue production in the previous year’s crop. A well-established relationship between residue production and optimum nitrogen fertilizer rate would allow farmers to: i) better manage nitrogen fertilizer inputs as they vary from field-to-field and year-to-year as a function of residue production, and ii) manage residue for lower optimum nitrogen rates.

Publications:

Funders: Iowa Nutrient Research Center

Disclaimer: This is an active research site, please contact Michael Castellano (castelmj@iastate.edu) prior to planning any site visits.