While we are taking stock of our past practices, present challenges, and future possibilities to cope with global warming – minimizing the use of fossil fuels and sequestering CO2 are generally accepted as useful strategies to reduce the warming effects. Biomass can be a source of fuel and/or an efficient cost effective means to sequester CO2 equivalent (CO2e) in plant materials and soil. However, growing biomass for these purpose involve making difficult land use choices as exemplified in the “food vs. fuel” debate. Moreover, it will be best if growing biomass for fuel or sequestration can be ecologically sound, encouraging biodiversity and improving soil. In Ohio alone, there are >280,000ha of previously surface mined land that are either severely degraded or with very low productivity potential. In 2008, at The Wilds in the Appalachian Ohio, a conservation-restoration team has initiated a long-term research in an 8.5ha area to establish high-diversity prairie on the reclaimed coal mine land. The objectives are to optimize biomass growth while encouraging diversity and to document the process to foster replication. The above-ground biomass can be used as feedstock for fuel while the root biomass will add essential organic matters improving the soil and sequestering CO2e. The first two years of establishment involved dividing the area into 10 replication blocks where each block was further divided into plots for various treatments, including land preparation: sub-soiling and tilling; six seed application: four single and two sets of multiple prairie species mixes with grasses, forbs, and legumes applied @430-500seeds/m2; fertilizer (di-ammonium phosphate) application @ 112kg/ha in half of the blocks selected at random in the second year; plus mow-management at the beginning of the growing season.
Results/Conclusions
In the first year, the vegetation grew up to 60cm with a number of volunteer species, however, prairie species establishment increased in the second year. Based on the ground observation, a set of ancillary plots were established in the second year in a 0.4ha area to test two levels of high diversity prairie seed mixes (13 and 30 species) with constant phylogenetic variance on land with no till/low impact preparation. The current estimated biomass harvest potential is 3.1 metric ton ha−1 year−1 and sequestration potential is 3.7 megagram of CO2 ha−1 year−1. The research will progressively provide specific information on establishment, performance, and maintenance of low-input high diversity prairie in previously surface mined land to enable land owners and researchers to replicate.
