Carbon Storage in the Soil and the Role of Root Morphology

Plant roots play a key role in the transfer of carbon from atmosphere to soil and through this process they contribute to reducing atmospheric CO ₂ and help mitigate climate change. However, it is uncertain which root traits control root-derived C influx. We propose that fine root length is of greatest interest, because the finest roots in a root system continuously exude carbon into soil. With this study we ask how different varieties of switchgrass and big bluestem -bioenergy crops- differ in specific root length (SRL; root length/ root weight) and relate these differences to plant-derived soil carbon. We collected soil samples from 10 years old plants in May 2018 (0-10cm depth) at Fermilab in Batavia, Illinois, and analyzed SRL and soil C. Preliminary data show that SRL is greater in big bluestem than switchgrass roots, and this coincides with more plant-derived C in soils dominated by big bluestem. Our results will provide greater understanding of how root traits in bioenergy cropping systems contribute to soil carbon sequestration.