Soil Carbon and Nitrogen Fractions Under Biofuel Cropping in the Piedmont of North Carolina.

As our country considers new sources of energy, biofuel crops are a source that is ever-present in that conversation. These “energy canes” can be used for heat and electricity generation, for production of fiber composite products, feed for livestock, and fuelstock for ethanol production. Our research will help determine the potential of these crops to grow on marginal lands, to mitigate greenhouse gas emissions and give us a better understanding of how they affect soil in the southeastern US.          

Switchgrass, giant miscanthus, sweet sorghum, tall fescue hay, and corn/rye-soybean cropping were managed in small plots on a Typic Kanhapludult near Salisbury, North Carolina for five years prior to sampling soil at depths of 0-6, 6-12, 12-20, and 20-30 cm. We hypothesized that perennial biofuel crops would lead to greater rooting and deposition of soil organic carbon and nitrogen, more so near the soil surface than at lower depths.

We will determine the differences in soil organic carbon and nitrogen, as these are important indicators of soil fertility and providing suitable habitat for soil organisms. The ability of soil to function as a living entity will be determined by measuring the respiration of carbon dioxide from soil. How soil provides nitrogen to plants will be determined through incubation of soil at standard temperature (25 C) and moisture (50% water-filled pore space) for 24 days in the laboratory.

 Our research will provide stepping stones for further research and will also provide insight for industry representatives and for policymakers.