Prairies were historically the dominant land use in Iowa, yet today less than 0.1% remain. Examining profit-gaining uses for prairies, in addition to highlighting their environmental benefits, may be an effective means of reincorporating prairie back into the landscape. In this project, we conducted a study that examined prairie plants managed for bioenergy production, wrote an extension publication that described the opportunities and benefits of using prairies in farm landscapes, and helped farmers to establish prairies on their farms that can be used as demonstration sites for other farmers. We found that there is great interest among farmers and landowners to learn more about prairies.
Before European settlement, more than 85% of Iowa’s landscape was tallgrass prairie (Sampson & Knopf 1994). Today, it is estimated that less than 0.1% of Iowa remains as either virgin or restored prairie (Sampson & Knopf 1994). The primary reason for this dramatic decline in prairie is conversion into cropland (Kurtz 2001), the majority of which is currently used to grow two annual crops: corn and soybean (USDA NASS 2008). Environmental advantages of prairies over annual crops include decreased soil erosion (Kort et al. 1998; McLauchlan 2006), decreased nutrient leaching (Donner & Kucharik 2008), more efficient use of soil nutrients through complementary patterns of resource use among diverse species (Skinner et al. 2006), increased wildlife habitat (Parrish & Fike 2005), and increased native plant species richness.
Potentially dramatic changes in agriculture are likely to occur in the foreseeable future. Inexpensive fossil energy will likely become less available as fossil fuel reserves diminish (Deffeyes 2006) and global demand for fossil energy increases (US EIA 2008a). This will necessitate changes in most of Iowa’s agriculture, which is heavily reliant on large inputs of externally derived nutrients and requires large inputs of herbicides or physical weed management (Liebman et al. 2008). Greater development of the carbon trading market will also provide strong incentives to reduce the carbon footprint of crops. The carbon footprint of crops can be reduced both by decreasing the amount of external industrial inputs used to produce the crops and growing crops that are better able to sequester carbon belowground (Tilman et al. 2006). In addition to becoming more environmentally benign, our agriculture will also be expected to produce more products, especially liquid transportation fuels (US House 2007). These changes in agriculture provide a great opportunity to develop cropping systems that are both environmentally beneficial and economically viable. Prairies grown as feedstocks for cellulosic biofuel production are one type of cropping system that can capitalize on these opportunities.
The primary objective of this project was to work with farmers, prairie conservation and farm organizations, and Iowa State University (ISU) Extension personnel to demonstrate and assess the opportunities and challenges of incorporating native tallgrass prairies into working farm landscapes.
The project had five short-term outcomes:
1) determine the effects of prairie functional group identity and diversity and nitrogen fertilization on productivity of prairies grown as biomass feedstocks,
2) disseminate knowledge of prairies grown as biomass feedstocks to farmers and ISU Extension field agronomists statewide through existing extension workshops,
3) inform farmers of the opportunities and challenges of applied uses for prairies on working landscapes through an extension publication,
4) provide tangible demonstration of prairies managed for multiple applied uses through field days, and
5) aid farmers in establishing prairies within their farms.
In the intermediate-term this research was to increase awareness among farmers of the opportunities that are available to incorporate prairies into working landscapes and the compositions of prairies that are best suited to different applied uses. In the long-term we expect that greater exposure to prairies used in working landscapes will prompt farmers to grow prairies on more of the landscape.
The general approach of this project was to provide farmers with information and exposure to native tallgrass prairie systems as a potential cropping system through three primary components: 1) data collection and results dissemination of prairies grown as biomass feedstocks from an established experiment at the ISU Agronomy Farm, 2) an extension publication and field days describing the environmental benefits and economic opportunities of incorporating prairies onto working landscapes for biomass and other applied uses such as carbon sequestration, and 3) technical and practical assistance to farmers interested in incorporating prairies onto their lands.
Data collection of prairies grown as biomass feedstocks occurred at a field experiment that was established in May 2008 on the ISU Agronomy Farm in Boone County, IA. The experiment was designed to test the effects of prairie plant functional-group identity and nitrogen fertilization on productivity. Functional groups in prairies refers to groups of plants that have similar ecological roles, such as warm-season (C4) grasses, cool-season (C3) grasses, and leguminous forbs (legumes; Kindscher & Wells 1995). Increasing the number of functional groups has been found to increase productivity in some prairies due to complementarity of resource use (Hector et al. 1999, Gross et al. 2007, Isbell et al. 2008). Adding nitrogen fertilizer, however, often increases productivity but decreases diversity due to enhancement of the most productive species (Michalet et al. 2006). This experiment tests the relationships between prairie functional groups and nitrogen fertilization using a randomized block experiment with a 4 x 2 complete factorial design. Conventionally grown corn is also included in the experiment to allow for a comparison of the prairies with the current status quo for ethanol feedstocks. Data collected from the experiment include prairie species and functional group richness and evenness, intercepted photosynthetically active radiation (IPAR), aboveground biomass, and total soil carbon and nitrogen.
We disseminated the results of this experiment directly to farmers and ISU Extension field agronomists throughout Iowa via field days. Results from this experiment were also disseminated to the agronomic and ecological research communities through scientific papers and presentations at national society meetings.
An extension publication (“Incorporating prairies into multifunctional landscapes”) was written for use that was disseminated widely across the state of Iowa and regionally. The publication was complementary to other recent publications that have addressed the advantages of planting perennials on targeted portions of the landscape (Schulte et al. 2008) by focusing on the tradeoffs necessary to manage prairies for different purposes such as environmental protection, livestock grazing, hay production, bioenergy production, and carbon sequestration. The publication included knowledge gained from the above-described field experiment in addition to the results from experiments conducted throughout the North Central region.
We participated in multiple field days/workshops in which we presented information regarding ways to reincorporate prairies into the landscape. We presented at venues hosted by Iowa State University Extension, the Leopold Center for Sustainable Agriculture, and the Iowa Crop Improvement Association.
The establishment of prairies on working landscapes can be difficult for farmers because of the lack of knowledge about prairie site preparation and establishment, lack of knowledge about design of prairie seed mixes, and lack of access to high quality prairie seed. Yet the presence of prairies as working parts of the farm landscape are crucial as demonstration sites for farmers. Because the prairie establishment is a multiple year process, the goal of this project was to identify and assist four interested farmers in establishing prairies on their land. We provided technical assistance to the farmers in determining the locations, site preparation, desirable seed mixes, and management of the prairies and provided financial assistance in purchasing and planting the prairie seed. These farmers were encouraged to use the prairies as demonstration sites for other farmers in the future.
More complete descriptions of the results and discussions of their implications from the field experiment are presented in the publications described below (reprints of any of the publications can be obtained by e-mailing firstname.lastname@example.org). Below we highlight some of the major findings from the field research.
- Corn produced approximately twice as much harvestable yield as the most productive prairie system (Figure 1). Nitrogen fertilization generally increased prairie harvestable yield, but unfertilized warm-season grasses and multi-functional group mixtures became as productive as their fertilized counterparts over time (Figure 1).
- Nitrogen fertilization did not affect the bioenergy characteristics of prairie plants (Figure 2). Warm-season grasses had among the most favorable bioenergy characteristics with litter inter-sample variability, high theoretical maximum ethanol yields, and relatively high higher heating values (Figure 2).
- Corn has larger harvestable yields than prairie plants, but nutrient (N, P, and K) exports from the field are disproportionately larger in corn than nutrient exports from prairie systems (Figure 3). Prairie systems have greater root production, higher diversity, and generally greater resource capture than corn (Figure 3).
Educational & Outreach Activities
- Jarchow ME (in preparation)Using bioenergy feedstock production to increase landscape diversity. PhD dissertation, Iowa State University Jarchow ME, M Liebman, V Rawat, and RP Anex (in press) Functional group and fertilization affect the composition and bioenergy yields of prairie plants. Global Change Biology Bioenergy Jarchow ME and M Liebman (2012) Tradeoffs in biomass and nutrient allocation in prairies and corn managed for bioenergy production. Crop Science 52: pages TBD. Jarchow ME and M Liebman (2012) Nutrient enrichment reduces complementarity and increases priority effects in prairies managed for bioenergy. Biomass and Bioenergy 36:381-389 Jarchow ME and M Liebman (2011) Maintaining multifunctionality as landscapes provide ecosystem services. Frontiers in Ecology and the Environment 5(9):262 Jarchow ME and M Liebman (2010) Incorporating prairies into multifunctional landscapes: establishing and managing prairies for enhanced environmental quality, livestock grazing and hay production, bioenergy production, and carbon sequestration. Iowa State University University Extension PMR 1007, 25 pp. Available at: https://www.extension.iastate.edu/store/ListItems.aspx?Keyword=1007
- Jarchow ME and M Liebman (2011) Incorporating prairies into multifunctional landscapes module. Iowa State University Crop Advisor Institute. Available at: http://www.cai.iastate.edu/modules/module.aspx?modID=113 **Based on the extension publication, we developed a continuing education module for agricultural professionals.** Jarchow, M.E. (August 2011) Growing native: how do we do it? How to Conserve Beneficial Insects with Native Plants workshop, Boone County, IA **We participated in a one-day workshop for farmers and landowners that examined how native plants could be used to enhance beneficial insect abundances. It was hosted by Iowa State University and the Leopold Center for Sustainable Agriculture. There were approximately 50 attendees at the workshop.** Jarchow, M.E. (June 2011) Grasslands: reconstructing prairies on acreages. Homegrown Lifestyle webinar, broadcast from Iowa State University, Ames, IA **We gave a webinar as part of a 12-week short course titled Homegrown Lifestyle. The course was designed to educate people living on acreages on how they could manage their land to benefit the environment and was offered through Iowa State University Extension and Outreach. There were approximately 60 participants in the course.** Jarchow, M.E., M. Liebman, and R. Dietzel (September 2010) Comparing corn and prairie systems. Iowa State University Agronomist In-Service, Boone County, IA **We presented results from our research at the Iowa State University Agronomist In-Service training. It was attended by approximately 40 ISU county and state agronomy extension personnel.** Jarchow, M., M. Thompson, and M. Helmers (February 2010) Designing biofuel cropping systems to benefit farmers and the environment, Iowa Crop Improvement Association Annual Meeting, Ames, IA **We presented results from our research at the Iowa Crop Improvement Association annual meeting. The meeting was attended by approximately 60 Association members, most of whom where farmers.** Jarchow, M.E. and M. Liebman (August 2009) Field demonstration of the Diversity and Nitrogen (DIVN) experiment. Iowa State University Extension and Iowa Agriculture and Home Economics Experiment Station Field Day, Boone County, IA **We hosted a field day in conjunction with the Iowa State University University Extension and Iowa Agriculture and Home Economics Experiment Station. The field day was attended by approximately 30 farmers.** We also presented our results from this work at 18 scientific meeting or research symposia both locally and nationally. National meetings included meetings for the Agronomy Society of America, Ecological Society of America, and the Environmental Protection Agency. Through these meetings and symposia, our work was made available to thousands of scientists. Information gained from this research was used to help leverage funds ($111,000) from the US Environmental Protection Agency through the Science to Achieve Results fellowship.
This project has been successful in increasing awareness among farmers and landowners regarding the environmental benefits and potential profit-gaining uses for prairies. The extension publication “Incorporating Prairies into Multifunctional Landscapes” has been widely distributed and well received; more than 2,500 hard copies have been distributed in addition to electronic copies of the publication. We have also worked directly with four farmers to help them put prairies their farms. We expect these on-farm prairies to be used as demonstration sites for many years into the future.
Through this project, we believe that we helped to educate thousands of farmers, landowners, and extension personnel about potential benefits on reincorporating prairies onto the landscape. We know that more than 2,500 people received hard copies of our extension publication, and we talked with approximately 250 farmers, landowners, and extension personnel directly through our outreach activities. We also have helped four farmers establish prairies on their farms, which will act as demonstration sites to allow more farmers and landowners to see prairies on the landscape. We do not know, however, how many people actually planted prairie on their land based on this work. Even if this work did not result in the planting of prairies on the landscape today, we believe that this work was important in making knowledge about managed prairie systems available for when agricultural policy is more explicitly supportive of multifunctional agricultural systems.
Areas needing additional study
Our field experiment was conducted at the plot scale. We believe that landscape-scale experiments need to be conducted on managed prairie systems, such as on-farm trials.