Methods We sampled various points on the Annex landscape to determine baseline levels of pH, soil organic matter (SOM), and soil texture. The north turf was partitioned into 5 x 5.5 meter plots (sites A through L) and the south turf into sites M and N, where we sampled for pH and %SOM as indicated in the figure below. We sampled for soil texture at a lower resolution at sites marked by stars and numbered 1-6. Standard methods were used for soil analyses (Klute, 1986). Findings Literature Cited: Abrahamson, L., Robison, D., Volk, T., et al Sustainability and environmental issues associated with willow bioenergy development in New York (USA). Biomass & Bioenergy. 15: Giampietro, M., Ulgiati, S., and Pimentel, D Feasibility of Large-Scale Biofuel Production: Does an enlargement of scale change the picture?. Bioscience. 47: Kamm, J A New Class of Plants for a Biofuel Feedstock Energy Crop. Applied Biochemistry and Biotechnology. 113: Kintisch, E Sowing the Seeds for High Energy Plants. Science 25:478. Klute A Methods of Soil Analysis Part I. American Society of Agronomy. Madison, Wisconsin Klute A Methods of Soil Analysis Part III. American Society of Agronomy. Madison, Wisconsin , Lewandowski, I., Clifton-Brown, J., Scurlock, J., et. al Miscanthus: European Experience With a Novel Energy Crop. Biomass and Bioenergy. 19: Soil analysis of an urban landscape to evaluate its potential in supporting an educational low-input, high-yield biofuel garden. Elsa D. Hoffman, Georgia W. Skoirchet, and Laila S. Williams Systems Ecology (ENVS316) Fall 2008 Introduction In light of the non-renewable and environmentally degrading nature of fossil fuels, biofuels are becoming an increasingly worthwhile alternative fuel source (Giampietro et al., 1997). Biofuel results from the conversion of plant biomass to energy, a process that has a net CO 2 emission of zero (Kamm, 2004). A biofuel is considered any type of fuel that can be produced from a biomass substrate and that can be either mixed with or replace fossil fuels (Giampietro et al, 1997). Perennial grasses such as Panicum virgatum (switchgrass) and Miscanthus giganteus and hardwood trees such as Salix spp. (willow) and Populus spp. (poplar), are considered energy crops (Kamm, 2004). These plants can grow in temperate to warm climates, yield high amounts of biomass relative to corn and soybean and promote soil fertility through carbon sequestration (Yates, 2008). The largest pool for terrestrial carbon is found in soil (Sciencedaily, 2008). Therefore, when selecting biofuel species it is important to consider the plants' interactions with the soil in which they grow, including their ability to sequester carbon. Soil organic matter (SOM) in particular is an important characteristic governing soil health. Corn, a major ethanol source, must be replanted annually after harvesting, however, perennial grasses and trees require only a harvesting of their above ground biomass allowing for a retention of below ground carbon (Sciencedaily, 2008). A high cellulose content, necessary for making ethanol, is another important factor defining biofuel crop candidates (Kintisch, 2008). Perennial grasses such as switchgrass and Miscanthus yield more usable energy per acre than biodiesel derived from corn or soybeans (NSF, 2006). Tree species such as poplar and willow that exhibit rapid growth and have the ability to re-sprout continuously are ideal harvesting and converting into a solid fuel source (Mercker). In the effort to continue Oberlin College's leading role on issues concerning sustainability, we propose that the college create a biofuel garden on campus. Implementation of an educational biofuel garden at Oberlin would offer students, faculty and the community opportunities to learn about the botany, ecology and environmental benefits of biofuel crops. The proposed garden would be located at the AJLC Annex adjacent to the home of the environmental studies department. Objectives 1.To establish baseline conditions for pH, SOM and soil texture at the proposed garden site, to assess heterogeneity of soil properties at the site, and to assess conditions on a reference site on the same property that will not be planted with biofuels. 2.To make informed recommendations regarding species and planting for a biofuels garden. 3. To make recommendations regarding garden design, crop management and future research that might be used to assess effects of biofuel crops on soil development. pH ranged from 6 to 7.8 within sample sites A-N, with an overall average of 7.35, which is slightly basic. Miscanthus and switchgrass have been shown to grow well in this pH range (DEFRA, 2007). %SOM ranged from 4.6% to 11.4% with an average of 6.5% over the entire landscape. Samples J, M and N are considerably higher values which could be due to sampling mishaps. Recommendations Miscanthus: Because Miscanthus grows taller than switchgrass, we recommend planting it to the north of the switchgrass plots. Panicum virgatum (switchgrass): We recommend planting monocrops and polycrops of various switchgrass species, including some Ohio natives. Salix spp. (willow): Willows, at maturity, are tall and can shade out shorter plants; we suggest planting them on the perimeter to define the garden’s boundaries and to be an example of a woody biofuel crop. Populus spp. (poplar): Due to the same size issues as the willows, we suggest planting poplar trees only on the perimeter of the garden. After the initial planting, we predict that carbon content in the soil will increase over time due to switchgrass and Miscanthus’ ability to sequester carbon in their root systems (DEFRA, 2007). The soil texture analysis showed heterogeneity in the soil in the north AJLC annex site. Before any garden construction begins, we recommend homogenizing by thoroughly tilling the soil. This will create more consistent and dependable data for comparison experiments conducted on the site. Scale of Research Due to the limited size of the garden site, research on the actual production of biofuels may not be appropriate because one would need multiple large scale plots to get any respectable data on conversion of biomass to fuel. In light of this, we suggest future studies conduct experiments that are appropriate on a small scale such as: measuring pH and %SOM in the soil over time to monitor how growth of different plants and poly-cropping strategies affects soil fertility. measuring %SOM over time to quantify above and below ground carbon sequestration. Educational Possibilities making the garden available as learning tool to visitors by installing informative plaques about the garden and the role of biofuels. facilitating community workshops about biofuel crop cultivation. (DEFRA, 2007; Parish, 2005; OSU; Abrahamson, 1998; Mercker). Literature Cited (continued): Mercker, D. Biofuels Initiative: Short Rotation Woody Crops for Biofuel. The University of Tennessee Agricultural Experiment Station (US); [cited 2008 Dec 7] Available from: Mixed Prairie Grasses Better Source of Biofuel Than Corn Ethanol and Soybean Biodiesel. National Science Foundation Press Release [Internet] 2006 Dec 7. [cited 2008 Dec 7]. Available from: Ohio Trees: Populus (Poplar). Ohio State University Extention Service (US); [cited 2008 Dec 7] Available from: Parish, D., and Fike, J The Biology and Agronomy of Switchgrass for Biofuels. Critical Reviews in Plant Sciences. 24: Planting and Growing Miscanthus: Best Practice Guidelines. Department for Environment and Rural Affairs (UK); [updated 2007 Jul; cited 2008 Dec 7] Available from: Replacing Corn With Perennial Grasses Improves Carbon Footprint of Biofuels. ScienceDaily [Internet] Dec 5 [cited 2008 Dec 7]. Available from: Yates, D. Miscanthus can meet U.S. biofuels goal using less land than corn or switchgrass. News Bureau: University of Illinois At Urbana- Champaign [Internet] Jul 30. [cited 2008 Dec 7]: Available from: Comparison of %SOM and pH Baseline Measurements at the AJLC Annex ABCDEFGHIJKLMN Sample Sites %SOM pH Soil texture is an important determinant of both drainage and nutrient conditions. Using the soil texture data (percentages of clay, silt, and sand) and a soil class triangle, we found that the samples 1-6 were clay, clay loam, clay loam, clay, clay loam and silty clay loam respectively. The average soil texture for the entire landscape was 39% clay, 31% silt and 30% sand. Miscanthus, several species of switchgrass, poplar, and willow can tolerate growing in all these soils (DEFRA, 2007; Parish, 2005; OSU; Abrahamson, 1998).