Research Projects

Current Research Projects

Long-Term Tillage and Crop Rotations Study

Principal Investigator: Mahdi Al-Kaisi

Project Description:
There is a need to document long-term tillage practices and crop rotations impact on yield, agronomic relations and soil quality indicators.  The study consists of eight locations across the state in a complete randomized block design with tillage as the main plots of five tillage systems (No-tillage, strip-tillage, chisel plow, deep tillage and moldboard plow) for corn-soybean, corn-corn-soybean rotations and continuous corn.  The sites are located at eight research and demonstration farms across the state representing different soil associations and climatic conditions.

Project Objectives:

  • Evaluate the impact of five tillage systems and three cropping systems on the yield of corn and soybean.
  • Study the long-term impact of these tillage systems and cropping systems on soil quality indicators and soil carbon dynamics.
  • Evaluate the economic returns of different tillage and cropping systems.


Completed Research Projects

Corn Residue Removal Impacts on Soil Carbon Dynamics, Greenhouse Gas Emission and Nutrient Cycling

Principal Investigator: Mahdi Al-Kaisi

Personnel Involved: Jose Guzman

Project Description: 
Corn residue (stalk, leaves, cobs and husk) in the Corn Belt region is a potential feedstock source for biofuel production that may alleviate some of the United States' dependence on foreign fuel and net greenhouse gas emissions.  The current emphasis on using corn residue as a feedstock for future ethanol production presents a soil and environmental challenge that needs to be addressed.

This field study was established in the fall of 2008 in two locations in Iowa in a complete randomized block design in a split-split arrangement, with two tillage systems as a main plot and three levels of residue removal and six N rates to determine the short and long-term impacts of varying corn residue removal and N fertilization rates and tillage systems on soil, air and water resources.  The project has five anticipated outcomes which include reliable estimates of: (1) amount of C and nutrients removed and returned to the soil by residue, (2) soil C and N sequestration potential with different residue management practices, (3) amount of greenhouse gas emissions, (4) assessing needs for supplemental fertilization of following crops and the cost thereof, and (5) impacts on soil physical properties.

Project Objective:

  • Examine the interaction effects of corn residue removal rate, nitrogen (N) fertilization and tillage practices on continuous corn production, greenhouse gas emissions, soil C dynamics and nutrients cycling.

Soil Carbon Dynamics and Greenhouse Gas Emission Evaluation of Organic and Conventional Vegetable and Grain Cropping Systems

Principal Investigators: Mahdi Al-Kaisi and Kathleen Delate

​​​​​​​​​​​​​​Personnel Involved: Chris Pelzer

Project Description:
Despite the interest in organic agriculture and potential environmental and economic advantages over conventional crop production, there is still a need to determine the difference, if any, in environmental impacts between conventional and organic agriculture vegetable and grain cropping systems.  Of particular interest and importance is the difference in soil carbon pool changes and greenhouse gas emissions between organic and conventional cropping systems.

In spring 2010, a complete randomized block design study was established at the ISU Horticulture Station (Gilbert, IA).  The study focuses on evaluating two different cropping systems, consisting of organic and conventional corn and soybean and organic and conventional vegetable systems. All individual plots have at least 20 foot grass separation borders to follow National Organic Program (USDA-AMS) guidelines for organic crop certification.

Project Objectives: 
Determine the differences between organic and conventional agriculture systems in:

  • Change in soil carbon pool
  • Soil carbon sequestration potential
  • In-situ measurement of soil gas emissions (CO2, N2O, CH4 and NH3)
  • Carbon and nitrogen budgets as affected by cropping system and tillage system
  • Soil nitrate leaching measurement

Corn Cob Study 

Principal Investigators: Mahdi Al-Kaisi and Roger Elmore

​​​​​​​Personnel Involved: Carlos Tenesaca, Brad Oneal

Project Description: 
In recent times, a new approach for ethanol production has been explored by producing ethanol using lignocellulosic materials such as corn stovers and corn cobs.  This advance in technology will bring the first generation of cellulosic ethanol production, utilizing a wide range of cellulosic materials.  Corncobs are especially a relevant option across Iowa and the Midwest due to the prevalence of corn based agriculture.  New cellulosic ethanol technology offers more options for fuel production and could allow farmers to boost their income by selling corncobs.

One common practice for cob removal is to collect corncobs after harvest and pile them on the field until they are collected the following spring.  Preliminary results from this study show a slower and stunted corn growth in the cob pile areas where corncobs were stored over winter when compared with areas cleaned of corncobs.

Project Objectives:

  • Investigate the effects of corncob affected areas on corn plant growth and development the following season.
  • Analyze the effects of the corncob residue on soil chemical, biological and physical properties.
  • Determine the impact of corncob affected areas on grain yield.
  • Identify management practices to mitigate the corncob effect on subsequent crops.

Interaction Effects of Tillage and Cover Crops on Soil Carbon Dynamics and Water Quality

Principal Investigator: Mahdi Al-Kaisi

​​​​​​​​​​​​​​Personnel Involved: Greg Wilson

​​​​​​​Project Description:
Erosion of topsoil and non-point water pollution from crop land has become one of Iowa's largest problems.  Conservation tillage systems and extended crop rotations offer an alternative to minimize nitrate leaching and increase soil carbon.  The inclusion of cover crops with conservation systems presents an attractive alternative to achieve the improvement of both water and soil quality.  With increasing concerns in the areas of soil erosion and groundwater quality, significant interest has been developed to examine the interaction effect of tillage systems and cover crops on both soil and water quality parameters.

Project Objectives:

  • Evaluate the potential impact of different tillage systems coupled with a cover crop on soil nitrate movement.
  • Evaluate the effect of different tillage systems and cover crops on soil C stocks and soil aggregate C fractions. 
  • Assess the potential impact of different tillage systems and cover crops on selected soil properties.

Iowa Learning Farm

Principal Investigators: Mahdi Al-Kaisi, Rick Cruse, Mike Duffy, Mark Hanna, Matt Helmers, Lois Wright Morton

​​​​​​​Personnel Involved: Aaron Andrews, Jamie Benning, Carol Brown, Jackie Comito, Mary Holmes, John Lundvall, Laura Miller, Brad Oneal, Ann Staudt and Xiaobo Zhou

Project Description: 
The Iowa Learning Farm is a model for learning and exchanging ideas among farmers, government agencies, scientists, agribusinesses and the general public.  This project demonstrates conservation management systems with an emphasis on conservation tillage, cropping systems and nutrient management across Iowa, while promoting an efficient agriculture production system leading to agronomic, economic and environmental improvement through increased awareness and adoption of conservation systems and ethics.  The goal of this project is to help producers recognize resource problems by using conservation planning processes to implement conservation systems that improve soil and water quality.

Project Objectives:

  • Demonstrate field trials so producers can evaluate agronomic and economic information, share local wisdom and provide a place where "seeing is believing"
  • Utilize locally-led networks
  • Structure a state-wide educational program on the importance of residue management
  • Perform water quality modeling for estimating pollutant load reductions
  • Offer educational materials related to the social, agronomic, environmental and economic aspects of residue management and other conservation practices.
  • To build a Culture of Conservation that strengthens our individual and collective commitments to a set of values, beliefs and attitudes about the centrality of natural resources to our standard of living and quality of life.

Iowa Cover Crop Working Group

Principal Investigators: Mahdi Al-Kaisi, Sarah Carlson and Mark Hanna

​​​​​​​Personnel Involved: Kevin Dietzel, John Lundvall and Brad Oneal

Project Description:
Cover Crops can provide significant benefits to reduce soil erosion and improve soil and water quality, especially over winter in crop production fields (i.e., corn and soybean), when topsoil is most vulnerable to water erosion and there is increased potential of nutrient leaching to groundwater.  A living cover crop will increase the potential of active root systems to intercept soluble nutrients such as nitrate and provide a source of organic matter input through above and below ground biomass.

Selecting cover crop varieties and the short window of growing cover crops--particularly in the Midwest--are some of the challenges that producers and agronomists face.  Winter hardy varieties of cover crops are typically planted after the crops are harvested in the fall and provide cover for the soil until they are killed in the spring prior to planting of the next crop.  A multi-faceted demonstration and education program is necessary to educate producers and provide information to help them overcome these challenges.

Project Objectives:

  • Promote the use of cover crops to reduce soil erosion and improve soil and water quality.
  • Demonstrate successful establishment and management practices of cover crops across Iowa.
  • Identify management challenges and recommend management options to overcome these challenges.
  • Demonstrate how cover crops can improve soil quality.