Mixing Reconstructed Prairie with Cropland to Balance Food and Biofuel Production with Environmental Quality
Research and outreach efforts were successful in 2010. It was one of the wetter seasons in recent history at the Neal Smith National Wildlife Refuge, which allowed us to collect data in environmental conditions differing from past years. Native perennial vegetation continued to positively impact sediment and nutrient losses from watersheds via reduced surface water runoff. In addition to surface water, soil water and groundwater samples were collected throughout the field season. On June 25, the 4th annual stakeholders meeting was held to discuss research with interested parties, as well as tour the research field sites. Presentations were given by representatives of all research areas of concentration. The meeting was considered successful and informative by all who attended.
During 2010, efforts were focused on two objectives; 1) Quantify the impacts of integrating native perennial plants into agricultural fields by monitoring hydrologic flows and nutrient and sediment movement in experimental watersheds, and 2) Promote outreach to stakeholders.
Surface runoff was reduced by an average of 46% in watersheds that consist of 10% or 20% native prairie cover (Figure 1). As a result of the native plant community continuing to develop over time, this percentage of runoff reduction has continued to increase from values of 29 and 44% in 2008 and 2009, respectively.
Lower concentrations of sediment, total nitrogen and total phosphorus in surface runoff have been observed from watersheds that incorporate 10% or 20% of the area in native prairie as well (Figures 2 and 3). Post-treatment data on nutrient and sediment loss from the watersheds showed interesting trends in how the different spatial configurations and amounts of perennial cover influenced water and nutrient flows. Manuscripts on surface runoff, sediment loss, and nutrient loss are being prepared and will be submitted in 2011.
Soil water and groundwater samples have been analyzed for nitrate-nitrogen. Overall, after disturbance and tillage in the fall of 2006, an increase in nitrate-nitrogen concentration was observed starting in about August 2007. In general, lower nitrate-nitrogen concentrations were found in those areas with native vegetation both in soil water and groundwater samples. This is more evident at monitoring locations at the toe of the watersheds. Despite the relatively young age of these established prairie patches, it appears there is a positive impact on nitrate-nitrogen concentrations. This work has been published in the Journal of Environmental Quality.
For the fourth consecutive year, a stakeholders meeting was held at the Neal Smith National Wildlife Refuge, near Prairie City, IA. This meeting allowed researchers to disseminate their findings to interested parties in attendance. Attendees representing 8 groups, ranging from academic, environmental, wildlife, and agricultural interests were present. After the presentations, a guided tour of field research sites was given to show how and where the information was gathered.
- Figure 1: Surface runoff in 2007, 2008, 2009, and 2010 (PFS – prairie filter strips)
- Figure 2: Sediment export in 2007, 2008, 2009, and 2010 (PFS – prairie filter strips)
Impacts and Contributions/Outcomes
Impacts and Contributions/Outcomes:
Throughout the year, a number of presentations were given at local and national conferences and peer-reviewed publications produced. They are listed below:
Hernandez-Santana, V, Zhou, X, Helmers, MJ, Asbjornsen, H, Kolka, R. 2010 Fall Meeting, AGU, San Francisco, CA (13-17 December, 2010). Perennial strips reduce runoff and contaminant export in annual cropping systems in the corn belt region, USA.
MacDonald, A.L. and L.A. Schulte Moore. 71st Midwest Fish and Wildlife Conference, Minneapolis, MN (12-15 December, 2010). Avian community composition and habitat use within watersheds of contrasting annual-perennial vegetation configurations.
Helmers, M. Cedar River Watershed Coalition, Waterloo, IA (12 November, 2010). Incorporating native prairie on agricultural land for reducing runoff and improving water quality.
Helmers, M., H. Asbjornsen, X. Zhou, R. Kolka, M. Tomer and R. Cruse. ASA, CSSA, and SSSA 2010 International Annual Meetings, Long Beach, CA (31 October – 4 November). Integration of perennials in rowcrop agriculture for enhancing water quality in central Iowa. (Poster presentation)
Liebman, M. Environmental Defense Fund, Science Day, San Francisco, CA (26 October, 2010). Balancing agricultural productivity with environmental quality in the Corn Belt.
MacDonald, A.L. Iowa Ornithologists Union Fall Meeting, Neal Smith NWR, Prairie City, IA (23 October, 2010). Blurring the lines between conservation and agriculture: bird use of prairie strips in crop fields.
Helmers, M. Anatomy of Iowa Floods: Preparing for the Future, Des Moines, IA (21 October, 2010). Trends and strategies in water run-off.
Liebman, M. Iowa State University, One Health Symposium: People, Plants, and Animals, Ames, IA (15 September, 2010). STRIPS: Science-based Trials of Row-crops Integrated with Prairies.
Harris, M. 2010 Ecosystem Management Seminar Series, University of New England, Armidale, NSW Australia (2 September, 2010). Ecosystem services in an agricultural landscape.
Liebman, M. Western Illinois University, Allison Farm field day, Roseville, IL (12 August, 2010). Managing cropping systems to address challenges from weather, energy costs, and weeds.
Liebman, M. Soil and Water Conservation Society, workshop on managing agricultural landscapes for environmental quality, Denver, CO (29 April, 2010). The role of bioenergy in sustainable landscapes.
Liebman, M. and M. Helmers. Midwest Organic and Sustainable Education Service, Organic Farming Conference, La Crosse, WI (25-27 February, 2010). Prairie strips for habitat enhancement and erosion control.
Helmers, M. Tallgrass Prairie Center seminar, Cedar Falls, IA (March, 2010). Using Perennial Vegetation to Reduce Nutrient and Sediment Loss in Surface Runoff.
Helmers, M. Iowa Water Conference, Ames, IA (March 2010). Landscape Scale Nutrient Reductions from Nonpoint Sources: Science Perspective.
Liebman, M. University of Wisconsin-Madison, Grasslands bioenergy symposium, Madison, WI (16 February, 2010). King Corn and the prairie.
Liebman, M., M.J. Helmers, and L. Schulte Moore. In press. Integrating conservation with biofuel feedstock production. In: M. Schnepf (ed.), Managing Agricultural Landscapes for Environmental Quality II. Soil and Water Conservation Society of America, Ankeny, IA.
Perez-Bidegain, M., M. J. Helmers, and R. Cruse. 2010 Modelling phosphorus transport in an agricultural watershed using the WEPP model. Journal of Environmental Quality. 39: 2121-2129.
Zhou, X., M., M.J. Helmers, H. Asbjornsen, R. Kolka, M.D. Tomer. 2010. Perennial filter strips reduce nitrate levels in soil and shallow groundwater after grassland-to-cropland conversion. Journal of Environmental Quality.39:2006-2015.
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