Search results

Iowa landscape
Land Management

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.


Funders:  Iowa Nutrient Research Center

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


Grazing cover crops

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.  


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. 

Bioreactor site prep

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.   


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. 

LiDAr image showing conservation practices
Nutrient Management

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 at


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.


Bioreactor installation

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. 

Archived soils samples from nitrogen fertilizer rate trials going back 20-30 years.  These will be incubated for 24-hour CO2 Burst, a test for soil microbial activity, to look relationship with economic optimum nitrogen rate.
Nutrient Management

Title:  Investigating the double-impact of soil health promoting practices on water quality

Location:  Boone

Time Period:  2019-2021

Research Team:  Marshall D. McDaniel, Morgan P. Davis, Wendong Zhang, and John E. Sawyer

Project Description:  A common assumption is that soil health promoting practices also reduce nitrate leaching and improve farm profits – but little evidence exists to back this up.  That is until two recent, independent studies both showed that soil CO2 Burst, a soil health indicator and measure of microbial activity, negatively correlated with fertilizer nitrogen needed to achieve optimal corn yield.  However, the link between the soil CO2 Burst and corn nitrogen needs remain highly variable, and the ability of management practices to increase CO2 Burst is largely unknown.  This study will investigate this ‘Double Impact’ of soil health promoting practices – that is their ability to reduce nitrogen leaching AND increase soil nitrogen supply to crops.


Funders:  Iowa Nutrient Research Center

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

Long term rotation study
Land Management

Title:  The Marsden farm experiment: A long-term investigation of how cropping system diversification and crop-livestock integration affect sustainability

Location:  Iowa State University Marsden Farm, Boone, Co., Iowa

Time Period:  2001-present

Research Team:  Matt Liebman and Matt Woods

Project Description:  Sustainable farming practices are intended to minimize the use of non-renewable resources, decrease the emission of pollutants into water and air, retain and regenerate soil, and protect human health. They are also intended to maintain or increase farm productivity and profitability while reducing reliance on purchased inputs. A central tenet of sustainable farming systems is that careful stewardship of diverse ecological communities can be used to replace a substantial portion of the mineral fertilizers, synthetic pesticides, and petrochemical energy used in conventional farming systems.

 Since 2001, we have used a 9-hectare (22-acre) field experiment at the Iowa State University Marsden Farm to investigate how cropping system diversification and crop-livestock integration affect productivity, profitability, and environmental quality. Three systems have been compared within the experiment: a 2-year corn/soybean rotation, a 3-year corn/soybean/oat + red clover rotation, and a 4-year corn/soybean/oat + alfalfa/alfalfa rotation. The 3-year and 4-year systems have periodically received cattle manure. By 2006, each of the plots had passed through at least one complete cycle of its respective rotation system.

For the ‘core set’ of comparisons among experimental treatments, the 2-year corn-soybean system has been managed with conventional rates of mineral fertilizers and herbicides, whereas the more diverse 3-year and 4-year systems have been managed with lower rates of agrichemicals. The experiment has also been used for a number of short-term component studies investigating a wide range of factors that can affect agroecosystem performance, including weed seed consumption by mice and insects, nitrogen mineralization from soil organic matter, and weed and crop responses to different ‘technology packages’ involving crop genotypes (transgenic versus non-transgenic) and weed control regimes (broadcast herbicides versus banded herbicides plus interrow cultivation).

Key results that have emerged from the study are as follows:

  • During the period of 2006-2016, mineral N fertilizer use was 86% and 91% lower, and herbicide use was 96% and 97% lower in the 3-year and 4-year systems, respectively, than in the 2-year system.
  • Corn yield has averaged 4% higher (p<0.0003) and soybean yield has averaged 16% higher (p<0.0001) in the more diverse systems compared with the 2-year system.
  • Weed management has generally been effective regardless of rotation, with weed biomass in corn and soybean averaging <22 kilograms per hectare (20 lb per acre) in all systems.
  • Incidence and severity of sudden death syndrome, a key disease affecting soybean in the Corn Belt, have been markedly lower in the longer rotations than in the 2-year rotation.
  • Three indicators of soil quality–particulate organic matter carbon, microbial biomass carbon, and potentially mineralizable nitrogen–were 22% to 51% higher in the 3-year and 4-year rotations than in the 2-year rotation. 
  • Spring (March-May) concentrations of nitrate in drainage water collected from corn in the more diverse systems were 57% lower (p<0.005) than from corn in the 2-year system.
  • Soil erosion was 50% lower, fossil energy consumption was 60% lower, and freshwater toxicity associated with herbicide use was 93% lower in the more diverse systems than in the conventional system.
  • During 2008-2016, increases in rotation length led to greater labor requirements and decreased gross revenue. However, production costs also dropped substantially as cropping system diversity increased. Consequently, net returns to land and management did not differ among systems (p=0.56, mean=$845 per hectare per year, $342 per acre year), though profitability tended to rise as rotation length increased.

Collectively, results of this long-term study indicate that diversification of conventional corn-soybean systems with small grains and forage legumes, coupled with integration of those systems with livestock, can allow for large reductions in the use of mineral fertilizers and herbicides and lead to less environmental damage, equivalent profitability, improved soil quality, and higher crop productivity. Thus, the diversified, integrated crop-livestock systems we have investigated are in many ways more sustainable than a conventionally managed corn-soybean rotation. Translating these potential gains in agricultural sustainability into broad-scale changes in the U.S. Corn Belt will likely depend on combinations of factors that include government policies, farmer confidence, technical support, and markets for ‘non-conventional’ products.

Publications:  Chen, X., X. Wang, M. Liebman, M. Cavigelli, and M. Wander. 2014. Influence of soil quality on carbon mineralization response to residue and nitrogen fertilizer additions. PLOS ONE 9(7): e103720, doi:10.1371/journal.pone.0103720.

Cruse, M.J., M. Liebman, D.R. Raman, and M. Wiedenhoeft. 2010. Fossil energy use in conventional and low-external-input cropping systems. Agronomy Journal 102: 934-941, doi:10.2134/agronj2009.0457; erratum: doi:10.2134/agronj2009.0457er.

Davis, A.S., J.D. Hill, C.A. Chase, A.M. Johanns, and M. Liebman. 2012. Increasing cropping system diversity balances productivity, profitability and environmental health. PLoS ONE 7(10): e47149. doi:10.1371/journal.pone.0047149.

Gómez, R., M. Liebman, and G. Munkvold. 2013. Weed seed decay in conventional and diversified cropping systems. Weed Research 54: 13-25.

Gómez, R., M. Liebman, D.N. Sundberg, and C.A. Chase. 2012. Comparison of crop management strategies involving crop genotype and weed management practices in conventional and more diverse cropping systems. Renewable Agriculture and Food 28: 220-233.

Heggenstaller, A.H. and M. Liebman. 2006. Demography of Abutilon theophrasti and Setaria faberi in three crop rotation systems. Weed Research 46: 138-151.

Heggenstaller, A.H., F.D. Menalled, M. Liebman, and P.R. Westerman. 2006. Seasonal patterns in post-dispersal seed predation of Abutilon theophrasti and Setaria faberi in three cropping systems. Journal of Applied Ecology 43: 999-1010.

Hunt, N., J. Hill, and M. Liebman. 2019. Cropping system diversity effects on nutrient discharge, soil erosion, and agronomic performance. Environmental Science and Technology, doi:10.1021/acs.est.8b02193.

Hunt, N., J. Hill, and M. Liebman. 2017. Reducing freshwater toxicity while maintaining weed control, profits, and productivity: effects of increased crop rotation diversity and reduced herbicide usage. Environmental Science and Technology 51: 1707–1717, doi:10.1021/acs.est.6b04086.

Jordan, N.R., and A.S. Davis. 2015. Middle-way strategies for sustainable intensification of agriculture. Bioscience 65: 513-519.

King, A.E., and K.S. Hofmockel. 2017. Diversified cropping systems support greater microbial cycling and retention of carbon and nitrogen. Agriculture, Ecosystems and Environment 240: 66-67. 

Lazicki, P., M. Liebman, and M. Wander. 2016. Root parameters show how management alters resource distribution and soil quality in conventional and low-input cropping systems in central Iowa. PLOS ONE 11(10): e0164209, doi:10.1371/journal.pone.0164209.

Leandro, L.F.S., S. Eggenberger, C. Chen, J. Williams, G. Beattie, and M. Liebman. 2018. Cropping system diversification reduces severity and incidence of soybean sudden death syndrome caused by Fusarium virguliforme. Plant Disease 102, doi:10.1094/PDIS-11-16-1660-RE.

Liebman, M., B. Baraibar, Y. Buckley, D. Childs, S. Christensen, R. Cousens, H. Eizenberg, S. Heijting, D. Loddo, A. Merotto Jr., M. Renton, and M. Riemens. 2016. Ecologically sustainable weed management: How do we get from proof-of-concept to adoption? Ecological Applications 26: 1352–1369.

Liebman, M., L.R. Gibson, D.N. Sundberg, A.H. Heggenstaller, P.R. Westerman, C.A. Chase, R.G. Hartzler, F.D. Menalled, A.S. Davis, and P.M. Dixon. 2008. Agronomic and economic performance characteristics of conventional and low-external-input cropping systems in the central Corn Belt. Agronomy Journal 100: 600-610.

Liebman, M., M.J. Helmers, L.A. Schulte, and C.A. Chase. 2013. Using biodiversity to link agricultural productivity with environmental quality: results from three field experiments in Iowa. Renewable Agriculture and Food Systems 28: 115-128, doi:10.1017/S1742170512000300.

Liebman, M., Z.J. Miller, C.L. Williams, P.R. Westerman, P.M. Dixon, A.H. Heggenstaller, A.S. Davis, F.D. Menalled, and D.N. Sundberg. 2014. Fates of Setaria faberi and Abutilon theophrasti seeds in three crop rotation systems. Weed Research 54: 293–306.

Liebman, M. and L.A. Schulte. 2015. Enhancing agroecosystem performance and resilience through increased diversification of landscapes and cropping systems. Elementa: Science of the Anthropocene, doi:10.12952/journal.elementa.000041.

O’Rourke, M.E., A. Heggenstaller, M. Liebman, M.E. Rice. 2006. Post-dispersal weed seed predation by invertebrates in conventional and low-external-input crop rotation systems. Agriculture, Ecosystems and Environment 116: 280-288.

O’Rourke, M.E., M. Liebman, and M.E. Rice. 2008. Ground beetle (Coleoptera: Carabidae) assemblages in conventional and diversified crop rotation systems. Environmental Entomology 37: 121-130.

Osterholz, W., M. Liebman, and M.J. Castellano. 2018. Can soil nitrogen dynamics explain the yield benefit of crop diversification? Field Crops Research 291: 33-42, doi:10.1016/j.fcr.2018.01.026.

Osterholz, W.R., O. Rinot, M. Liebman, and M.J. Castellano. 2016. Can mineralization of soil organic matter meet maize nitrogen demand? Plant and Soil, doi:10.1007/s11104-016-3137-1.

Osterholz, W.R., O. Rinot, A. Shaviv, R. Linker, G. Sanford, J. Strock, M. Liebman, and M. Castellano. 2017. Predicting gross nitrogen mineralization and potentially mineralizable N using soil organic matter properties. Soil Science Society of America Journal, doi:10.2136/sssaj2017.02.0055.

Poffenbarger, H., G. Artz, G. Dahlke, W. Edwards, M. Hanna, J. Russell, H. Sellers, and M. Liebman. 2017. An economic analysis of integrated crop-livestock systems in Iowa, U.S.A. Agricultural Systems 157: 51-69, doi:10.1016/j.agsy.2017.07.001.

Poffenbarger, H.J., D.C. Olk, C. Cambardella, J. Kersey, M. Liebman, A. Mallarino, J. Six, and M.J. Castellano. 2020. Whole-profile soil organic matter content, composition, and stability under crop rotations differing in belowground inputs. Agriculture, Ecosystems, and Environment, doi:10.1016/j.agee.2019.106810.

Rinot, O., W. Osterholz, M.J. Castellano, R. Linker, M. Liebman, and A. Shaviv. 2018. Excitation–emission matrix fluorescence spectroscopy of water extractable organic matter to predict nitrogen mineralization rates in soil. Soil Science Society of America Journal, doi:10.2136/sssaj2017.06.0188.

Tomer, M.D. and M. Liebman. 2014. Nutrients in soil water under three rotational cropping systems, Iowa, USA. Agriculture, Ecosystems and Environment 186: 105-114.

Wattenburger, C.J., L.J. Halverson, and K.S. Hofmockel. 2019. Agricultural management affects root-associated microbiome recruitment over maize development. Phytobiomes Journal. doi: 10.1094/PBIOMES-03-19-0016-R.

Westerman, P.R., M. Liebman, F.D. Menalled, A.H. Heggenstaller, R.G. Hartzler, and P.M. Dixon. 2005. Are many little hammers effective? Velvetleaf population dynamics in two- and four-year crop rotation systems. Weed Science 53: 382-392.

Williams, C.L., M. Liebman, P.R. Westerman, J. Borza, D. Sundberg, and B. Danielson. 2009. Over-winter predation of Abutilon theophrasti and Setaria faberi seeds in arable land. Weed Research 49: 439–447.

Funders:  USDA Agriculture and Food Research Initiative, Leopold Center for Sustainable Agriculture, Iowa Soybean Association, and Iowa Nutrient Research Center

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

Mriganka De sampling stream water at Tipton Creek (42.317819, -93.251334).
Nutrient Management

Title:  Does quantity and quality of tile drainage water impact in-stream eutrophication potential? Evidence from a long-term biofuel cropping systems experiment.

Location:  Boone

Time Period:  2019-2021

Research Team:  Marshall D. McDaniel, Mriganka De, Michael L. Thompson, Matt Liebman, and Matthew J. Helmers

Project Description:  The challenge with farming is balancing crop nutrient needs while minimizing losses.  Fertilizer nitrogen (N) and phosphorus (P) are added to agricultural fields to increase yields, but these nutrients also limit algal growth in the aquatic ecosystems and in excess can lead to eutrophication. Tile drainage is used extensively across the U.S. Midwest to also improve yields, but these tile drainage lines can directly transport nutrients to streams - effectively bypassing natural stream buffers. The quantity (i.e. load) and quality (i.e. chemical composition of nutrients and carbon) of the tile drainage water likely plays a crucial role in stream water quality, but most tile drainage studies focus on only the quantity of total dissolved and inorganic forms of N and P. This, however, may not be giving us the whole story of how tile drainage water can affect stream water quality. Instead, we propose to delve further into the chemical forms of N and P (and dissolved organic carbon) in tile drainage water, and look at how management practices affect these. Furthermore, we will evaluate the eutrophication potential of the same tile water in order to gain a more comprehensive understanding of the effects of tile drainage water on stream water eutrophication. We will analyze tile drainage water samples from an ongoing, long-term experiment near Boone, IA called the Comparison of Biofuel cropping Systems (or COBS). The COBS experiment consists of five treatments: continuous corn, corn-soybean, corn with cover crop, fertilized prairie, and unfertilized prairie. Our specific research objectives are to:

1.  Assess the impact of the five different management practices on chemical composition and bioavailability of dissolved organic matter in tile drainage water.

2. Determine the eutrophication potential of tile drain water from these different management practices.


Funders:  Iowa Nutrient Research Center

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


Streambank erosion on Onion Creek in Story County, Iowa

Title:  Phosphorus contributions from eroding streambanks

Location:  Onion Creek, Story and Boone Counties, IA; Nishnabotna River watershed, SW Iowa

Time Period:  2016-2019

Research Team:  Peter Moore, Forrest Williams, Tom Isenhart, John Kovar, John Thomas (Hungry Canyons Alliance), Colton Dodson.

Project Description:  Stream bed and bank erosion represents a significant contribution to phosphorus (P) export from Iowa’s streams, worsening downstream eutrophication and water quality concerns.  The size of this contribution is not well known in time or space, and may depend on many factors including watershed size, geomorphology, land use, stream channelization history and hydrological regime, and soil composition and texture. This project investigated the distribution of streambank erosion in time and space in two contrasting watersheds in Iowa. Erosion and P export was monitored in the field monthly over a two-year period in the Onion Creek watershed, a 20 square-mile catchment on the Des Moines Lobe near Ames. Remote sensing and GIS methods were developed to study the same processes within the much larger Nishnabotna River watershed (2806 square miles) in the deep-loess region of southwest Iowa.

Publications:  Williams, F., 2019, AIMM: A method for measuring bank erosion on a statewide scale, Graduate Theses and Dissertations. 17360.

Funders:  Iowa Nutrient Research Center, Hungry Canyons Alliance


Turf grass as a cover crop
Land Management

Title:  Perennial turfgrass cover crops in maize production systems

Location:  Sorenson Research Farm, Ames

Time Period:  2019-2021

Research Team:  Shui-zhang Fei, Ken Moore, Andrew Lenssen, and Allen Chen

Project Description:  The current crop production system in the Midwest is highly productive but it negatively impacts the environment in a number of ways including non-point source nutrient pollution in waterways, soil erosion and declining soil quality. Growing annual cover crops can be a partial solution to these problems, however, the cost of annual planting, increased potential for corn root diseases, and the narrowed planting windows for subsequent crops continue to be hurdles to the widespread adoption of annual cover crops. Growing cool-season grasses with corn or soybean as perennial ground cover (PGC) provides similar benefits as annual cover crops but it does not require costly annual replanting or delayed planting of row crops. Many cool-season grasses that are commonly used as lawn grasses possess characteristics that make them ideal ground covers for maize and soybean: preference for cool, moist weather, shallow roots, good shade tolerance and winter hardiness. Our previous research indicated that Kentucky bluegrass grown concurrently with conventionally managed corn can produce comparable corn yields to a no-grass control, and Sandberg bluegrass which exhibits distinct summer dormancy can perform similarly. This proposal seeks to investigate the compatibility of PGC with maize by growing a diverse set of cultivars of Kentucky bluegrass and Sandberg bluegrass as PGC.  We will investigate above and below-ground nutrient dynamics and the potential of using PGC to reduce non-point nitrogen and phosphorus pollution. Team members include Shuizhang Fei, professor of Horticulture, Andy Lenssen and Ken Moore, professors of Agronomy and Allen Chen, Ph.D. candidate.  


Funders:  Iowa Nutrient Research Center

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